# A Systematic Review of Medicinal Plants of Kenya used in the Management of Bacterial Infections

Authors: Elizabeth A. Odongo; Peggoty C. Mutai; Beatrice K. Amugune; Nelly N. Mungai
Journal: Evidence-Based Complementary and Alternative Medicine
 (2022)

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## Abstract

Kenya’s vision 2030 partly aims at ensuring adequate health care for all, and the integration of traditional healthcare practices into the national healthcare system would present a more rapid alternative towards the realization of universal health coverage in Kenya. Currently, research on Kenyan medicinal plants with potential antibacterial activity remains vastly fragmented across numerous literature studies and databases; thus, it is imperative to collate and appraise these data for the ease of future research and possible clinical application.Objective. This review aims at exploring and compiling research evidence on medicinal plants used in the management of bacterial infections in Kenya, with a focus on their efficacy and safety. Methodology. A comprehensive web-based systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was executed to highlight the Kenyan medicinal plants used for the management of bacterial infections in Kenya. This review includes studies published until January 2021 from the PubMed, Science Direct, AJOL, and Google Scholar databases. Results. A total of 105 Kenyan medicinal plants belonging to 43 families have their in vitro activity against various human pathogenic bacteria evaluated. Plants from the Lamiaceae, Rutaceae, and Fabaceae families were the most commonly studied. Aloe secundiflora, Toddalia asiatica, Senna didymobotrya, Warbugia ugandensis, Tithonia diversifolia, Fuerstia africana, Olea africana, and Harrisonia abyssinica were the plants frequently evaluated within Kenya. The plants with the strongest antimicrobial activities were Toddalia asiatica, Hagenia abyssinica, Ocimum gratissimum, Harrisonia abyssinica, Senna didymobotrya, Olea Africana, Camellia sinensis, and Tarmarindus indica. Conclusion. Based on a published work, it is evident that traditional medicine is seemingly an acceptable and efficient system among Kenyan communities in the management of bacterial infections. Kenya’s rich biodiversity with diverse secondary metabolites presents a promising source of new therapeutic alternatives with possibly different mechanisms of action against bacteria.


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## Body

## 1. Introduction

Despite the remarkable investment in health care witnessed over the past decade, microbial infections remain a major threat to human and animal health and are a cause of morbidity and mortality especially in low- and middle-income countries (LMICs). The rising cases of antibiotic resistance present a major health problem globally, and there is an immediate need for strategies to manage it as it relentlessly compromises the effectiveness of antimicrobial therapy and increases the threat of therapeutic failure [1–3]. Due to an inefficient antimicrobial resistance (AMR) surveillance system, the exact liability of AMR in Kenya is indefinite although cases such as reduced susceptibility of community-acquired pneumococci, Vibrio cholera outbreaks, and methicillin-resistant Staphylococcus aureus (MRSA) from hospitalized patients have been reported [4].Herbalism is the most preferred form of traditional medicine and is highly lucrative in the international market with annual sales ranging from US dollar 5 billion in Western Europe to US dollar 14 billion in China [5]. In Africa, herbal products are available in most markets in the urban centers and rural areas [6]. Irrespective of the accessibility to modern medicines, various communities in Kenya (either deliberately or due to economic limitations) utilize medicinal plants for the management of microbial infections and other diseases; thus, various legislations are actively being formulated to regulate this practice [7]. Presently, there are over 400 plant species used for the management of common diseases in East Africa documented in several ethnobotanical [8–10].As a developing nation with numerous healthcare challenges such as the high costs of medications, Kenya needs to grow its scientific base and create logical and effective solutions to manage them. Laboratory investigations and various clinical trials have often suggested the positive effects of phytomedicines bothin vivo and in vitro; however, there has been little systematic appraisal of their benefits [11]. Due to their unrivaled chemical diversity, plants offer the infinite potential for innovative and effective antimicrobial agents, but there is the scantiness of information in regard to their efficacy and their safety levels [12]. Critical consideration to the prospect of producing pharmaceutical products using local raw materials is a worthy endeavor to ensure the affordability of drugs. In a bid to provide herbal practitioners and consumers with insight, this study primarily aimed at evaluating the bioactivity of Kenyan medicinal plants useful in the management of bacterial infections.


## 2. Materials and Methods

A comprehensive web-based systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines on identification, screening, eligibility, and inclusion was executed to highlight the medicinal plants used for the management of bacterial infections in Kenya. This review covers published literature from 1994 up to January 2021 obtained from the PubMed, Science Direct, African Journals Online (AJOL), and Google Scholar databases. Grey literature [13] from the local university repositories and conference proceedings were also included in this review [14].The literature search was performed using search terms identified from previous similar reviews. The Boolean search operators (AND and OR) were used to effectively combine the search terms [15]. The following search terms were used: Kenya AND antimicrobial plants OR Kenyan AND antimicrobial plants. Kenyan AND antibacterial plants OR Kenyan AND antibacterial plants. Kenya AND traditional medicine AND antimicrobial plants OR Kenyan AND traditional medicine AND antimicrobial plants, Kenya AND traditional medicine AND antibacterial plants OR Kenyan AND traditional medicine AND antibacterial plants, Kenya AND ethnopharmacological AND antimicrobial plants OR Kenyan AND ethnopharmacological AND antimicrobial plants and Kenya AND ethnopharmacological AND antibacterial plants OR Kenyan AND ethnopharmacological AND antibacterial plants [16].Screening of search outputs was performed in two stages. First, the title and abstract of identified journal articles/theses were overviewed based on PICO (Participants Intervention Comparison and Outcomes) and the studies classified as “yes” or “no” based on the information provided by the title and abstract. Thereafter, suitable articles/theses were downloaded and critically assessed for inclusion in the review [16].The studies eligible for inclusion were limited to the English language. The assessment of eligibility of studies was performed by at least two people, independently, using the Critical Appraisal Skills Programme (CASP) appraisal checklist as a guide [16]. This study excluded research data from papers with poor methodology and retracted studies. The quality of the papers was assessed based on study design, description of the subject, method and assay, variables assessment, control groups, and data collection. To minimize bias, data extraction from selected study reports was independently performed by two reviewers and any disagreements resolved through discussion with the third reviewer [17].


## 3. Results

The study included research data from the pharmacological assays/ethno-medicinal studies reporting on Kenyan medicinal plants used for the treatment of bacterial infections. The initial database search identified a total of 105, 157 articles. After removing the duplicates (n = 15000), 89857 studies were excluded based on the title and abstract. Three hundred (300) full-text articles were assessed for eligibility, from which 211 were excluded based on scope, methodological approach, and very little/no bioactivity reported. A total of seventy-nine (79) studies regarding the in vitro antibacterial activity of Kenyan medicinal plants were ultimately included in the review. No in vivo studies within Kenya on Kenyan medicinal plants with antibacterial activity were found.Data collected included herbal plant name, plant family, part of plant used for extraction, extraction/preparation method, concentrations of extracts, bacteria species, data on reported activity, toxicity, exposure time, geographical information, the year of publication, and the first author (Table1). A total of 105 medicinal plants from 43 families were studied for in vitro activity against various human pathogenic bacteria. Plants from Lamiaceae, Rutaceae, and Fabaceae families were the most common (Table 1).Table 1
Systematic review of Kenyan antibacterial medicinal plants.
PlantEthnopharmacological usePart usedBioactivityAssay method usedCollection site in KenyaSide effects/contraindications/toxicityReferencesAloe secundiflora Engl. (Asphodelaceae)Candidiasis, diarrhea, sore throat, and wound healingLeavesThe ethanol leaf extract exhibited a ZOI of 17.0 ± 0.8 mm compared to 8.4 ± 0.7 mm (erythromycin) and 8.0 ± 0.8 mm (gentamycin) againstStreptococcus pneumoniaeDisk diffusion methodEastern KenyaNone reported[18]Wounds, appetizer, and malariaThe methanol leaf extract (100 mg/ml) exhibited a ZOI of 17 ± 1 mm againstStaphylococcus aureus, 18 ± 2 mm, Bacillus subtilis, 17 ± 2 mm. K. pneumoniae, and 19 ± 2 mm against E. coliAgar well assayDepartment of Biological Sciences, Egerton UniversityNot reported[19]Stomachache, polio, malaria, and chest problemsThe methanol leaf extract (1 g/ml) exhibited a ZOI (13.0 ± 0.17 mm) compared to (25.0 ± 1.06) ciprofloxacin againstS. aureus, ZOI (17.0 ± 1.38 mm) compared to (20 ± 2.47 mm) against E. coli, and ZOI (18 ± 0.35 mm) compared to (22.0 ± 1.06 mm) ciprofloxacin against E. faecalisDisk diffusion methodKenyatta University ArboretumNot reported[20]StomachacheThe methanol leaf extract had an MIC of 9.375 mg/mL againstP. aeruginosa compared to amoxicillin 4.687 mg/mL, MIC of 18.75 mg/mL compared to amoxicillin 4.687 mg/mL against E. coli (MIC and MBC of 37.5 mg/mL compared to amoxicillin 4.687 mg/mL against S. aureus and S. typhi)Broth dilution methodLake Victoria Region of KenyaNot reported[21]Wound healingThe methanol leaf extract had an MIC (mg/ml) of 9.1 and an MBC (mg/ml) of 10.4 and exhibited a ZOI of 16 ± 1.27 mm againstE. coli compared to ciprofloxacin 17 ± 1.38 mmDisc diffusion method/broth dilution methodKenyatta University ArboretumNot reported[22]Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae)Constipation, stomach pains, liver pains, indigestion and sore throats and as an antiviralLeavesThe ethyl acetate leaf extract exhibited a ZOI of 8.0 ± 0.5 mm againstStreptococcus pneumoniae, compared to 2.4 ± 0.6 mm (gentamycin) 2.2 ± 0.4 mm (erythromycin)Disk diffusion methodEastern KenyaA 70% ethanol extract of the aerial parts was toxic to the kidney and liver toxicity at the lowest dose tested (400 mg/kg).T. diversifolia should be used with caution as it may be toxic especially in prolonged use at higher doses[18, 23]DiarrheaThe methanol leaf extract (1 g/ml) exhibited ZOI of 21.6 mm, 19.3, and 18.0 againstS. aureus, P. aeruginosa, and K. pneumoniae compared to amoxicillin 23.0 mm, 17.3 mm, and 17. 66 mm, respectively, MIC of 37.5 mg/ml against S. aureusAgar disc diffusion method/broth dilutionTwiga Region in Central Province[24]Skin infectionsThe ethyl acetate leaf extract exhibited a ZOI of 18.2 mm againstS. typhi compared to chloramphenicol with a ZOI of 23.3 mm and ciprofloxacin with a ZOI of 26.0 mmDisc diffusion methodNyamira County[25]Gastrointestinal disordersThe dichloromethane leaf extract (25 mg/mL) exhibited a ZOI of 18 mm againstS. aureus and 14 mm against P. aeruginosaAgar well diffusion methodUniversity of Kabianga Botanical Garden, Kericho County[26]Senna didymobotrya (Fresen.) Irwin & Barneby (Caesalpiniaceae)Skin diseases, diarrhea, dysentery, laxative, malariaRoots, Stem barks, leavesThe methanol root extracts exhibited a ZOI of 1.58 cm compared to streptomycin (1.30 cm) againstS. aureusDisk diffusion methodKibuye, Kisumu CountyThe methanol and dichloromethane crude root extracts of had an LD50 of 1927 mg/kg after a period of 14 days. the extracts at high concentration and at a high dose tend to be toxic[27, 28]Malaria, skin conditions, livestock infectionsThe methanol stem bark extracts (100 mg/ml) had a ZOI of 19.0 mm compared to 30μg/ml gentamycin (19.0 mm) against S. aureus, ZOI (11.0 mm) compared to 30 μg/ml gentamycin (9.0 mm) against MRSA, ZOI (12.0 mm) compared to 30 μg/ml gentamycin (17.0 mm) against K. pneumoniaeDisk diffusion methodBomet District[29]DiarrheaThe methanol leaf extracts (1 g/ml) had ZOI (16.0 mm) compared to (60.0 mm) gentamycin (10μg/ml) against B. subtilis. The methanol extracts (1 g/ml) had ZOI (16.0 mm) compared to (24.0 mm) gentamycin (10 μg/ml) against S. aureusDisk diffusion methodRarieda[30]Diarrhea, fevers, abscesses of the skeletal muscles, and venereal diseasesThe methanol 2.5% root bark extract and 7.5% stem bark extracts here inhibited the growth ofS. aureus, which was also observed in streptomycin (1 g/L)The area under disease progress stairs (AUDPS)Siaya, Nakuru, and Nandi counties[31]Oral infectionsThe ethanol leaf extract (1 mg/mL) exhibited a ZOI of 21.70 ± 0.88 mm, againstP. gingivalis and (MIC 0.13 ± 0.00 mg/mL and MBC 0.50 ± 0.00 mg/mL). Amoxicillin had a ZOI of 40.3 mmAgar well diffusion assayBorabu Sub-county in Nyamira County[32]Toddalia asiatica L. (Rutaceae)Food poisoning, malaria, and sore throatFruits, stems, barks, roots, leavesThe essential oil (10μL) exhibited a ZOI (mm) of 21.00 ± 2.08 against E.coli, 22.33 ± 1.67 against MRSA and 19.00 ± 1.16 S. aureus compared to tetracycline 26.00 ± 0.58 against E.coli, 9.00 ± 0.58 against MRSA and 11.67 ± 0.88 S. aureusDisc diffusion methodMaseno area, Kisumu CountyThe root extract showed LD50 >1000 mg/kg and CC50 >100 μg/ml[33, 34]Malaria and diureticThe stem bark methanol extract (1 g/ml) had a ZOI of 16.67 ± 0.67 mm againstS. aureus compared to gentamycin (1.0 μg/disc) 25.33 ± 0.67Disc diffusion methodKakamega Forest[35]TB and measlesThe methanol root extract exhibited a ZOI (mm) of 7.0 againstE.coli, 6.33 against S. typhi, and 8.66 against S. aureus compared to tetracycline 20.22 against E.coli, 16.00 against S. typhi, and 21.33 S. aureus. MIC and MBC of 9.375 mg/mL against S. typhi and S. aureusAgar disc diffusion (DD) method broth microdilution techniqueBondo (Alego)[36]Skin infections, bronchial pains, and stomachacheA formulated antiseptic herbal detergent exhibited ZOI of 24.30 ± 0.67 mm, 18.00 ± 0.58 mm, 16.00 ± 0.58 and 19.67 ± 0.67 mm against MRSA,P. aeruginosa. E.coli, and S. typhi, respectively, compared to the commercial hand wash 21.67 ± 0.33 mm, 19.67 ± 0.67 mm, 13.67 ± 0.33 mm and 18.33 ± 0.33Disc diffusion methodSlopes of Kajulu Hills, Lake Victoria Basin[37]Malaria and fluThe stem bark DMSO extract exhibited an ZOI of 10 ± 0.3 mm compared to flucloxacillin 10 ± 0.1 mm against MRSAAgar well diffusion methodNarok[38]Harrisonia abyssinica Oliv. (Simaroubaceae)Stomachache, abdominal pains, fever, nausea, vomiting, plague, swollen testicles, dysentery, gonorrhea, tuberculosisWhole plant, leaves, barks, berriesThe methanol whole plant extract had MIC (6.25 mg/ml) compared to (>1 mg/ml for antibiotic standards) againstS. aureus and P. aeruginosa and MIC (250 mg/ml) against E. coliBroth dilution methodMeru Central DistrictThe methanol root bark extract had LC50 (μg/ml) of 198.498 and was considered cytotoxic[39, 40]Pneumonia, malaria, and eye ointmentThe methanol leaf extract had an MIC of 100, 15.6, 75, 150 mg/mL againstS. aureus B. cereus, P. aeruginosa, and E. coli, respectively, compared to that of 0, 0, 0.25 , 0.25 mg/mL of streptomycin against S. aureus B. cereus, P. aeruginosa, and E. coli, respectively, and benzylpenicillin 0.6, 0.6 against S. aureus and B. cereusBroth dilution methodMachakos and Kitui[39]Fever, tuberculosis, and snake biteThe methanol-dichloromethane extract (100 mg/ml) had an ZOI of 20.1.6 mm compared to (18.1.2 mm) gentamycin againstS. aureus methanol-dichloromethane extract (100 mg/ml) had an ZOI 30.1.7 mm compared to (15.1.3 mm) gentamycin against E. coliAgar diffusion assayBondo District in Nyanza Province[41]Infertility, menstrual problems, and stomach pain menstrualThe crude extracts showed a moderate activity againstS. aureus (11 mm), B. subtilis (7.8 mm), P. aeruginosa (7.0 mm), E. coli (8.5 mm)Disc diffusion methodChuka, Meru-South District, Tharaka Nithi County[42]Fuerstia africana T. C. E. Fr. (Lamiaceae)Urinary problems, tongue infections, diarrhea, skin infectionsLeaves, aerial partsThe methanol leaf extracts (1 g/ml) exhibited a ZOI of 17.0 mm compared to (26.0 mm) gentamycin (10μg/ml) against B. subtilis. The methanol extracts (1 g/ml) had a ZOI of 19.0 mm compared to (24.0 mm) gentamycin (10 μg/ml) against S.. aureus, methanol extracts (1 g/ml) had a ZOI of 20.0 mm compared to (26.0 mm) gentamycin (10 μg/ml) against MRSADisk diffusion methodKisii southExtracts were found to be safe at 5000 mg/kg body weight per day. median lethal dose (LD50) of methanol and DCM extracts is >5000 mg/kg[30, 43]Eye ailments, toothacheThe hexane leaf extract (100 mg/ml) exhibited a ZOI of 10.67 ± 0.33 mm compared to (17.33 ± 0.33) chloramphenicol (30μg/ml) against S. aureus, ZOI (10.50 ± 0.29 mm) compared to (15.00 ± 0.00) chloramphenicol (30 μg/ml) against MRSA, and ZOI (9.67 ± 0.33 mm) compared to (16.50 ± 0.29) chloramphenicol (30 μg) against P. aeruginosaAgar well diffusion methodOlenguruone, Nakuru County, and Cheptenye, Kericho County[43]BoilsThe methanol extract exhibited ZOI of (17.21 ± 0.22) compared to gentamycin (23.88 ± 0.01) againstK. pneumoniae, ZOI of (14.24 ± 0.35) compared to gentamycin (23.88 ± 0.01) against E. coli and ZOI of (15.18 ± 0.42) compared to gentamycin (25.9 ± 0.01) against S. aureusAgar well diffusionMagadi, Kajiado District of Kenya[44]Oral infectionsThe chloroform extract exhibited ZOI (15.88 ± 0.54) compared to chloramphenicol (21.7 ± 0.11) againstS. aureusAgar well diffusionVihiga County, Western Kenya[45]Olea africana (Oleaceae)Sore throat and urinary tract infectionsStem bark, barks, twigs, leavesThe ethanol stem bark extract (1 g/ml) exhibited ZOI (18.5 mm) compared to gentamycin (10μg/ml) 19.5 mm and a MIC of (62.5 mg/ml) against S. aureus. The methanol extract had a ZOI of 8.3 mm) compared to gentamycin (19 mm) against E. coli and ZOI of 9.8 mm compared to gentamycin (21.0 mm) against P. aeruginosaAgar well diffusion/broth dilutionBomet DistrictThe methanol leaf extract had an LD50 value of 3475 mg/kg was; thus, it is nontoxic[46, 47]Sap used for bone setting (fracture)The aqueous bark extract (1 g/ml) exhibited a ZOI of 10.2 ± 0.6 mm compared to (18.0 ± 0.1) streptomycin (25μg/ml) against S. aureusDisk diffusion methodMbeere, and Embu-Eastern Province[48]Chewing stickThe methanol extract exhibited a ZOI of 12.4 mm againstS. aureus, MIC of 1.5 mg/ml against E.coli and 0.30 mg/ml against S. aureusBroth dilution methodUniversity of Kabianga Botanical Garden, Kericho County[49]Chewing stickThe methanol leaf extract (25 mg/mL) exhibited ZOI 18 m againstPseudomonas aeruginosa, ZOI 19.20 mm against S. aureus and 17 mm against E. coliBroth dilution methodUniversity of Kabianga Botanical Garden, Kericho County[26]Carissa edulis Vahl. (Apocynaceae)Malaise, antiviral, and appetizerRoots, stem, leavesThe ethanol root extract exhibited a ZOI of 8.0 ± 0.9 mm againstS. pneumoniae compared to 7.2 ± 0.1 mm (gentamycin) and 7.8 ± 0.3 mm (erythromycin)Disk diffusion methodEastern KenyaThe oral LD50 of the extract was estimated to be >5000 mg/kg. generally safe at doses lower than 1000 mg/kg is in rats ()[18, 50]Kidney problems, pneumoniaMICs and MBCs of 37.50 mg/ml againstS. typhiBroth dilutionTransmara West[51]Gonorrhea, asthmaThe methanol extract exhibited a ZOI of 9.00 mm againstS. typhi compared to amoxicillin 16.0 mm and both MIC and MBC of 37.5 mg/mL against S. typhi and S. aureusAgar disc diffusion method/broth microdilution techniqueLake Victoria Region[36]Rhus natalensis Bernh. (Anacardiaceae)MalariaRoots, stems, barks and leavesThe methanol root extract had a MIC of 6.25 mg/against bothS. aureus and P. aeruginosa and had a moderate activity with inhibition zone diameters of 11.6 mm against S. aureus and P. aeruginosa compared to gentamycin 25.3 mm and 18 mmBroth dilution methodKilifi districtThe extracts were safe to the mammalian cells[52]Diarrhea and stomachacheThe isolated compound (1)-epicatechin exhibited a ZOI of 15 ± 0.3 mm againstS. aureus and (10 ± 0.2 mm) against P. aeruginosa compared to streptomycin 10 μg/disc 22 ± 0.2 mm and 20 ± 0.3 mm, respectivelyDisc diffusion methodKapkonga Iten, Eldoret town[53]Microbial infectionsThe isolated compound 1 had a ZOI of exhibited ZOI of 21 mm againstS. aureus compared to Chloramphenicol 20 mmAgar diffusion methodThika River in Gatanga division, Central Kenya[54]38. Prunus africana (Hoolh f.) Kalkman (Rosaceae)Arrow poisoning and gonorrheaBarks, stemsThe methanol bark extract showed a moderate activity againstS. aureus (11.0 mm), B. subtilis (10.7 mm), P. aeruginosa (9.7 mm), and E. coli (8.0 mm)Disc diffusion methodChuka, Meru-South District, Tharaka Nithi CountyThe bark had an LD50 of 2201 mg/ kg. The stem bark extract was determined to be nontoxic at the therapeutic dose of 500 mg/kg body weight[42, 55]DiarrheaThe methanol stem bark extract exhibited a ZOI of 20 mm againstS. aureus and MIC of 0.073 mg/ml. ZOI of 17 mm with MIC of 0.156 mg/ml against MRSA. ZOI of 15 mm and the MIC of 0.3125 mg/ml against P. aeruginosa. . ZOI of 12 mm and the MIC of 2.50 mg/ml against S. pneumoniaeDisc diffusion assayRift Valley Province of Kenya[56, 57]Chest pain and stomach problemsThe hydro-methanolic bark extract exhibited a ZOI of 17.33 ± 0.882 mm againstS. typhi and ZOI of 12.33 ± 0.333 mm against Escherichia coli compared to penicillin 27.67 ± 1.2 mm and 20.33 ± 0.333 mmAgar well diffusion methodUniversity of Eastern Africa, Baraton[58]Warbugia ugandensis Sprague (Canellaceae)Diarrhea, constipation and cough,Bark, roots, leaves, stem barkThe methanol extract (100 mg/ml) exhibited a ZOI of 15.0 mm compared to (18.0 mm) chloramphenicol againstS. aureus, ZOI (14.0 mm) compared to (24.0 mm) chloramphenicol against MRSA. The Dichloromethane extract had a MIC of 3.125 mg/ml against S. aureus and MRSADisc diffusion test/broth dilutionNgong ForestThe extract had a LD50 > 5000 mg/kg body weight. Extract displayed no apparent deleterious toxicity[55, 59]STIs, diarrhea, and bronchitisThe methanol extract exhibited ZOI of 3.169 ± 0.27 mg/ml againstS. aureusDisk diffusion methodRift Valley[60]Microbial infectionsThe methanol extract exhibited a ZOI of 19.33 ± 0.333 mm againstS. epidermidis compared to penicillin 26.67 ± 0.333, ZOI 17.00 ± 0.882 mm against B. cereus and ZOI 11.67 ± 0.333 mm against E. coli compared to penicillin 31.33 ± 0.333Disc diffusionNatural Forest around the University of Eastern Africa, Baraton[61]Hepatitis, gonorrhea tuberculosis, bronchitis, and pneumoniaThe stem bark extract of hexane exhibited a ZOI of 11.32 mm againstS. typhi compared to chloramphenicol 23.3 mm and ciprofloxacin 26.0 mmDisc diffusion testNyamira county[25]Sexually transmitted diseases, throat, and chest infections, diarrhea, and wounds/ulcersThe methanol extracts exhibited a ZOI of 30 mm, 28 mm, and 16 mm for the root, stem‐bark, and leaf extracts, respectively, at 100μg/ml concentration against E. coli. The ZOI for the water extracts was 20 mm, 18 mm, and 12 mm for the root, stem‐bark, and leaf extracts, respectively, at an equivalent concentration of 100 μg/ml compared to Norfloxacin 23 mm. The extracts had an effective MIC of 42 μg/mlDisc diffusion method/broth dilutionJomo Kenyatta University of Agricultural and Technology (JKUAT) Botanical Garden[62]Allium sativum L. (Liliaceae)Dysentery, spiceRhizome, bulbsGarlic juice exhibited a ZOI of 10.0 mm againstP. aeruginosa, 11.7 mm against E. coli, 14.7 mm against S. aureus and 17.7 mm for S. typhi. The activity of ampicillin on E. coli and S. typhi was 11.7 mm and 18.7 mm ()Disc diffusion testGithurai Market, NairobiThe LD50 was found to be 3034 mg/kg, and maximum tolerated dose was 2200 mg/kg[63, 64]Infection, coldsGarlic extract (GE) 200μl/ml/ exhibited a ZOI of 14 mm compared to gentamycin 24 mm against S. aureusDisc diffusion methodNakuru Municipal Council Market in Nakuru Town[65]Reduce blood lipids and blood pressureThe methanolic extract of garlic was effectiveagainst E. coli, Staphylococcus aureus, and Pseudomonas aeruginosa, with ZOI of 21 mm, 27 mm, and 28 mm, compared to tetracycline 19 mm, 22 mm, and 27 mm, respectively. The garlic methanolic (GM) extract had 0.14 μg/ml against S. aureus and P. aeruginosaAgar well diffusion method/broth dilutionKenyatta University[66]Camellia sinensis L. (Theaceae)BeverageLeavesGreen tea (0.1 mg/ml) exhibited a ZOI of 21.3 ± 0.33 mm againstE.coli compared to gentamicin 22.3 ± 0.50 mm and ZOI of 23.7 ± 0.33 mm against S. aureus compared to gentamicin 23.2 ± 0.28 mmAgar well diffusion methodTea Research Foundation, Kangaita Substation in KirinyagaThere were no observed adverse effects at 2500 mg/kg body weight/day[67, 68]The aqueous crude green tea extracts 400 mg/ml had a ZOI of 20 ± 0.0 mm againstS. aureus and MIC 100 mg/ml compared to streptomycin 20 ± 0.0 mm, ZOI of 18 ± 0.0 mm and MIC of 200 mg/ml against E. coli compared to streptomycin 10 ± 0.0 mmAgar well diffusion methodNgere in Murang’a County[69]Azadirachta indica A. Juss. (Meliaceae)Udder infectionsLeaves, barks, seedsThe neem extract (NE) 200μl/ml exhibited ZOI 11 mm against S. aureus compared to gentamycin 24 mmDisc diffusion methodKisauni in Mombasa CountyNot reported[65]Methanol bark extract exhibited ZOI of 25 mm, 24 mm, and 20 mm againstE. coli, P. aeruginosa, and S. aureus, respectively, with MIC (mg/ml) of 15, 17, and 16Disc diffusion methodChumani in Kilifi North Constituency[70]Tagetes minuta L. (Asteraceae)Intestinal disorders and stomach problemsLeavesThe methanolic leaf extract exhibited a ZOI of 17 ± 1.94 mm againstS. aureus compared to vancomycin 25.0 mm and ciprofloxacin 22.0 mm (MIC 8.9 mg/ml; MBC 10.0 mg/ml)Disc diffusion test/broth dilutionKenyatta university arboretum[20, 71]Oils may cause irritation to the skinThe methanol extract had a MIC (mg/ml) 8.7 and MBC (mg/ml) 10 and ZOI of 16 ± 1.27 mm againstE. coli compared to ciprofloxacin 20 ± 3.11 mmDisc diffusion method/broth dilution methodKenyatta University Arboretum[22]Adansonia digitata L. (Bombacaceae)OpthalmiaLeaves, barksThe synthesized AgNPs exhibited a ZOI of 17.1 ± 0.130 mm againstE. coli and 12.9 ± 0.082 mm against S. aureus compared to ciprofloxacin with a ZOI of 33.4 ± 0.443 and 12.9 ± 0.082 mm against E. coli and S. aureusDisc diffusion technique.Makueni CountyThe stem extracts are non-toxic to brine shrimp larvae[72, 73]Diarrhea, dysenteryThe organic extract at 200 mg/ml and 100 mg/ml showed the highest inhibition zones of 14.33 mm and 12 mm, respectively, againstMRSA compared to gentamycin 15.5 mmDisc diffusion techniqueMsambweni District[74]Euclea divinorum Hern (Ebenaceae)Toothbrush, constipation and ulcersStems, barks, leavesThe DCM stem bark extract exhibited ZOI (mm) of 10.8 ± 0.26 againstP. aeruginosa and 17.0 ± 0.42 against S. aureus compared to Augmentin 10.0 ± 0.02 against P. aeruginosa and 27.0 ± 0.02 against S. aureusDisc diffusion methodBunyala (Budalang‟i) district of Busia CountyThe root extracts have toxic effects and should be used with care; gargling of extracts is recommended instead of swallowing[75, 76]Dental cariesThe ethanolic root bark extract had MIC of 25, 50, 25 and 25μg/ml for S. pyogenes, S. aureus, E. coliBroth dilutionElgeyo Marakwet, Rift Valley[77]Salvadora persica L. var. persica (Salvadoraceae)Chest problems, stomachache, teeth problemsRoots, stems, barksThe organic root extract had 10 GUs (numerical growth units) at 0.5 mg/ml againstM. tuberculosis compared to Isoniazid that had zero GUs at 0.5 mg/mlBACTEC mgIT™ 960 systemVarious conservancies in SamburuHigh concentrations >5 g/kg of the mammal’s body weight can result in toxicity[36, 78]Oral thrush and diarrheaThe methanol bark extract exhibited a ZOI of 21.66 mm againstS. aureus compared to Amoxicillin 21.3 mm. ZOI of 20 mm against P. aeruginosa compared to amoxicillin 14.33 mm. ZOI of 15 mm against E. coli compared to amoxicillin 23.6 mmAgar disk diffusion techniqueNkaroni, Wamba Division, Samburu District[79]Plectranthus barbatus Andrews Lamiaceae)Oral and throat infectionsLeaves, rootsThe DCM: MeOH crude leaf extract 200 mg/ml and 100 mg/ml exhibited ZOI (mm) of 13 and 10.3, respectively, against MRSA compared to 14 mm for amoxicillin [50 mg/ml]. The lowest MIC values were observed in DCM fraction (40 mg/ml) against MRSADisc diffusion technique/broth dilution techniqueVarious geographical regions of KenyaNot reported[80]Stomachache and woundsThe root extracts exhibited a ZOI of 18.67 mm, 20.00 mm, and 25.33 mm inS. aureus, MRSA, and B. cereus compared to streptomycin 39.67 ± 1.76 mm, 39.67 ± 1.76 mm, and 33.00 ± 1.15 mm ()Agar well diffusion methodMsambweni Subcounty, Kwale County[81]Cordia purpurea (Picc.) Aiton (Fabaceae)DiarrheaRoots, barksThe methanolic root extract exhibited a ZOI of 15 mm compared to (21.33 mm) amoxicillin againstS. aureus and ZOI (23.66 mm) compared to (17.58 mm) amoxicillin against P. aeruginosa. The methanolic extract had a MIC of 18.75 mg/ml compared to 18.75 mg/ml cefpodoxime against S. aureus and 18.75 mg/ml compared to 9.372 mg/ml cefpodoxime against P. aeruginosaAgar disc diffusion method/broth dilutionSamburu‐Wamba conservanciesNot reported[79]The methanolic extract exhibited a ZOI of 14.33 mm compared to (21.33 mm) amoxicillin against S. aureus and ZOI (19.66 mm) compared to (17.58 mm) amoxicillin against P. aeruginosa. The methanolic extract had MIC of 37.50 mg/ml compared to 18.75 mg/ml cefpodoxime against S. aureus and 37.50 mg/ml compared to 9.372 mg/ml cefpodoxime against P. aeruginosaAgar disc diffusion method/broth dilutionSamburu‐Wamba conservancies[79]Organic bark extract exhibited zero GUs at 0.5 mg/ml against M. tuberculosis andM. kansasii compared to Isoniazid that had zero GUs at 0.5 mg/mlBACTEC mgIT™ 960 systemVarious conservancies in Samburu[36]Croton macrostachyus Hochst. Ex Delile: (Euphorbiaceae)Diarrhea, stomach acheBarks, rootsThe ethyl acetate bark extract exhibited ZOI between 10.1 ± 0.6 mm and 16.0 ± 1.2 mm againstS. typhi, E. coli and K. pneumoniaeAgar disc diffusion methodBaraton Community in Nandi District of KenyaThe aqueous stem extract does not provoke death until the dose 16 g/kg. There is a wide margin of safety for the therapeutic use of the extract[82, 83]The methanolic extract exhibited a ZOI of 23.66 mm compared to (21.33 mm) amoxicillin againstS. aureus and ZOI (18.0 mm) compared to (17.58 mm) amoxicillin against P. aeruginosa. The methanolic extract had an MIC of 37.50 mg/ml compared to 18.75 mg/ml cefpodoxime against S. aureus and 18.75 mg/ml compared to 9.372 mg/ml cefpodoxime against P. aeruginosaAgar disc diffusion method/broth dilutionSamburu‐Wamba conservancies[79]Ocimum gratissimum L. (Lamiaceae)Ear infections, tooth gargleLeavesThe essential oil from leaves exhibited ZOI (26.6 ± 5.7 mm) compared to (24.5 ± 0.7 mm) chloramphenicol againstS. aureus. ZOI (21.7 ± 2.1 mm) compared to (32.5 ± 2.5 mm) chloramphenicol against E. coliAgar disc diffusion methodMeruThe oil can cause an inflammatory response[84, 85]Sore eyes and rectal prolapseThe essential oil from leaves extract had ZOI (21.7 ± 2.1 mm) compared to (28.0 ± 07 mm) chloramphenicol againstE. coli. ZOI (26.6 ± 5.7 mm) compared to (23.5 ± 2.1 mm) chloramphenicol against S. aureusAgar disc diffusion methodMeru District of Eastern Kenya[86]Ocimum suave Wild (Lamiaceae)Ear infections, cough and disinfectantLeaves, rootsThe methanolic leaf extract had a MIC of (6.25 mg/ml) compared to >1 mg/ml for antibiotic standards againstS. aureus and methanolic extract had an MIC of 31.25 mg/ml compared to >1 mg/ml for antibiotic standards against P. aeruginosa and E. coliBroth dilution methodMeru Central districtThe aqueous leaf extract is nontoxic in acute and subchronic intake. No gross abnormalities, teratogenic, or histological changes observed[40, 87]Stomach acheThe methanol root extract exhibited a mean ZOI of 14 mm againstS. aureus compared to amoxicillin 21.3 mm, ZOI of 21 mm against P. aeruginosa compared to amoxicillin 17.5 mm and ZOI of 18 mm against E. coli compared to amoxicillin 23.6 mmAgar disk diffusion techniqueNamunyak, Wamba division, Samburu district[79]Premna resinosa (Hochst.) Schauer (Compositae)Respiratory-related illnessesRootsDichloromethane root extract had a MIC of 31.25μg/ml against MRSA, while ethyl acetate fraction had a ZOI of 22.3  ±  0.3 against S. aureus compared to 33.7  ±  0.3 mm (oxacillin 10 μg/disc and gentamycin 10 μg), methanolic extract had a ZOI of 8.7 mm compared to (22 mm) oxacillin 10 μg/disc and Gentamycin 10 μg against S. aureus and ZOI 11.7 mm) compared to (24 mm) oxacillin 10 μg/disc and gentamycin 10 μg against E. coliDisc diffusion and microdilution techniquesMbeere community, KenyaThe dichloromethane and ethyl acetate fractions were within the acceptable toxicity limit (CC50 < 90)[88]Hagenia abyssinica (Bruce) JF Gmel (Rosaceae)Diarrhea, stomachache, tongue infections, soresStem bark, leavesThe dichloromethane/methanol stem bark extract exhibited ZOI of 19.0 mm againstS. aureus compared to Erythromycin (0.01 mg/ml) 22 mm, ZOI of 20.0 mm against E. coli compared to Erythromycin 0.01 mg/ml 20.0 mm, ZOI of 18 mm against B. subtilis compared to Erythromycin 0.01 mg/ml 20 mmAgar well diffusion methodAberdare ranges, Kiburu Forest StationThe extracts were safe at 5000 mg/kg body weight per day. Median lethal dose (LD50) of methanol and DCM extracts is >5000 mg/kg[43, 89]The hexane leaf extract (100 mg/ml) had a ZOI of 16.67 ± 0.67 mm compared to (17.33 ± 0.33) chloramphenicol (30μg/ml) against S. aureus, ZOI (19.33 ± 1.33 mm) compared to (15.00 ± 0.00) chloramphenicol (30 μg/ml) against MRSA and ZOI (13.00 ± 1.00 mm) compared to (16.50 ± 0.29) chloramphenicol (30 μg) against P. aeruginosaAgar well diffusion methodOlenguruone in Nakuru County and Cheptenye in Kericho County[43]Clerodendrum myricoides (Hochst.) R. Br. ex Vatke: (Lamiaceae)Respiratory diseases, tonsillitis, eye infections, gonorrheaWhole plantThe methanol extracts (1 g/ml) had a ZOI of 14.7 ± 0.3 mm compared to (17.0 mm) gentamycin (10μg/ml) against E. coli and ZOI (20.3 ± 0.3 mm) compared to (33.0 mm) gentamycin (10 μg/ml) against S. aureusDisk diffusion methodMbeere Community, KenyaThe methanol extracts within the acceptable toxicity limit with a CC50 of >500 μg/ml) the LD50 value of 3475 mg/kg and thus is non-toxic[90]PneumoniaThe aqueous extract (1 g/ml) exhibited ZOI (13.8 ± 0.2 mm) compared to (18.0 ± 0.1) streptomycin (25μg/ml) against S. aureusDisk diffusion methodMbeere, and Embu-Eastern Province[48]Securidaca longipedunculata Var. parvifolia (Polygalaceae)Infusion reduces swellingsRoots, barksThe aqueous extract (1 g/ml) had a ZOI of 12.5 ± 2.2 mm compared to (18.0 ± 0.1) streptomycin (25μg/ml) against S. aureusDisk diffusion methodMbeere, and Embu-Eastern ProvinceThe extract has an LD50 value of 771 mg/kg body weight and is nontoxic at relatively high concentrations[48, 91]Sexually transmitted infectionsThe bark and root extract exhibited ZOI of 20.1 mm and 13.5 mm, respectively, againstN. gonorrhoeae, compared to 12 mm and 19.1 mm ciprofloxacin and tetracyclineDisc diffusion methodBungoma County[92]Tarmarindus indica L. (Fabaceae)Meat preservativeFruit paste, barkThe water extract exhibited a ZOI of 34.67 mm, and 24 mm againstE. coli and S. aureus, respectively, compared to chloramphenicol 16 mm and 18 mmDisc diffusion testChepararia and Kongelai subcounties of West Pokot CountyThe pulp extract ofTamarindus indica at 3000 mg/kg and 5000 mg/kg body weight of resulted in no mortality and is practically nontoxic[93, 94]Diarrhea, typhoidBarkThe methanol bark extract (1 g/ml) had a ZOI of 14.5 mm compared to (24.0 mm) gentamycin (10μg/ml) against S. aureusDisk diffusion methodRarieda[30]Zanthoxylum chalybeum Engl. (Rutaceae)Malaria, pneumonia, sore throatLeaves, roots, barksThe methanol extracts (1 g/ml) had a ZOI of 16.0 mm compared to (26.0 mm) gentamycin (10μg/ml) against B. subtilisDisk diffusion methodKisii SouthThe acute oral median dose (LD50) of the root bark extract was >6750 mg/kg body weight. Plant is of relatively low toxicity[30, 95]The organic crude extract exhibited the good inhibition againstB. cereus at 200 and 100 mg/ml concentrations with a ZOI of 13.87 mm and 12.167 mm, respectively, compared to gentamycin 15 mmDisc diffusion techniqueMsambweni District[74]The organic extract exhibited mean inhibition zone values of 24.33 ± 0.33 mm against MRSA compared to streptomycin 39.67 ± 1.76 mmAgar well diffusion methodMsambweni Kwale County[81]Lantana camara L. (Verbenaceae)Skin rashes, boilsLeavesThe methanol leaf extract (1 g/ml) had a ZOI of 17.0 mm compared to gentamycin (10μg/ml) against S. aureusAgar well diffusionBomet DistrictFor short-term use, the extract exhibited very low toxicity, while long-term exposure results in liver and kidneys. the root extract was the most toxic part[46, 96]leavesThe organic leaf extracts MICs and MBCs of 37.5 mg/mL against bothS. aureus and P. aeruginosaBroth dilution techniqueAround Lake Victoria Region[36]Mangifera indica L. (Anacardiaceae)Burns, scalds, sores, abscesses, foodLeaves, fruitsThe methanol extracts (1 g/ml) had ZOI (18.5 mm) compared to gentamycin 10μg/ml (19 mm) against S. aureus, ZOI (13.0 mm) compared to gentamycin (20 mm) against E. coli, ZOI (17 mm) compared to 10 μg/ml gentamycin (18.5 mm) against P. aeruginosaAgar well diffusionBomet DistrictThe oral or dermal administration of the extract showed no lethality at the limit doses of 2,000 mg/kg body weight, and no adverse effects were found[46, 97]The methanol extract exhibited a ZOI of 2.07 ± 0.15) cmagainst S. aureus compared to norfloxacin at 10 μg 2.95 cm and ZOI 1.93 ± 0.09) compared to Norfloxacin at 10 μg 2.95 cm against E. coliDisc diffusion methodMakueni and Embu[98]Terminalia brownii Fresen (Combretaceae)Diarrhea, ulcers, and sexually transmitted diseasesBark, leaves, rootsThe ethanol extract had ZOI (mm) of 9.2 ± 0.3 compared to 6.8 ± 0.4 (gentamycin) and 6.6 ± 0.2 (erythromycin) againstS. pneumoniaeDisk diffusion methodEastern KenyaThe roots and stem bark extracts exhibited mild cytotoxic activity with LC50 values ranging from 113.75 to 4356.76 and 36.12 to 1458.81 μg/ml[18, 99]The aqueous leaf extract (1 g/ml) had a ZOI of 18.0 ± 0.8 mm compared to (18.0 ± 0.1) streptomycin (25μg/ml) against S. aureus, ZOI (11.7 ± 0.5 mm) compared to (16.0 ± 0.2) streptomycin (25 μg/ml) against E. coli, ZOI (12.8 ± 1.0 mm) compared to (15.0 ± 0.3 mm) streptomycin 25 μg/ml against B. subtilisDisk diffusion methodMbeere, and Embu-Eastern Province[48]Markhamia lutea (Benth.) K. Schum. (Bignoniaceae)Eye infectionBarkThe chloroform extracts had a ZOI of 22.82 mm against E.coli, 18.79 mm againstS. aureus and 17.94 mm against P. aeruginosa compared to gentamycin 22.27 mm, 22.52 mm, and 20.17 mm, respectivelyAgar well diffusionEmuhaya Sub-county, Western KenyaNot reported[100]Asparagus setaceous Kunth Jessop (Asparagaceae)Syphilis, gonorrheaAerial parts, rootsThe MIC values for ethanolic aerial part extract ranged from 3.2 mg/ml forS. aureus, 6.25 mg/ml for E. coli, and 25 mg/ml for B. subtilis, P. aeruginosa, and S. faecalis, while for the ethanolic root extracts of the same plant, MIC ranged from 6.25 mg/ml for S. aureus and B. subtilis to 25 mg/ml for E. coli, P. aeruginosa, and S. faecalisBroth dilutionGatunduNot reported[101]Caesalpinia volkensii Harm (Caesalpiniaceae)Bronchitis , pneumoniaLeavesThe MIC values for the ethanolic leaf extract was 6.25 mg/ml forS. aureus, 12.5 mg/ml for B. subtilis and 25 mg/ml for E. coli and P. aeruginosaBroth dilutionGatunduThe organic extract had a median lethal dose of >2000 mg/kg body weight, hence is safe[101, 102]Thylachium africanum Lour. (Capparaceae)DiarrheaBarkThe methanol extract exhibited a ZOI of 18.66 mm againstS. aureus compared to amoxicillin 21.3 mm, ZOI of 23.33 mm against P. aeruginosa compared to amoxicillin 17.5 mm, ZOI of 15 mm against E. coli compared to amoxicillin 23.6 mmAgar disk diffusion techniqueNamunyak, Wamba Division, Samburu DistrictNot reported[79]Alectra sessiliflora (Vahl) Kuntze (Scrophulariaceae)Diarrhea, sexually transmitted infections, woundsWhole plantThe methanol extract 50 mg/ml exhibited ZOI of 15.46 mm againstS. aureus compared to chloramphenicol 19.23 mm, ZOI of 10.72 mm against P. aeruginosa compared to chloramphenicol 19.22 mm, ZOI of 9.76 mm against E. coli compared to chloramphenicol 19.10 mmDisk diffusion methodVihiga countyNot reported[103]Teclea nobilis (Rutaceae)Colds and chest problemsLeavesThe DCM extract exhibited a ZOI of 10 mm againstS. aureus compared to gentamycin 13 mm and ampicillin 14 mmDisk diffusion methodSiroch, Keiyo Sub-county, Elgeyo-Marakwet CountyNot reported[104]Ochna thomasiana (Ochnaceae)Microbial infectionRoot, stem barksThe methanolic extract was found effective againstS. aureus and B. subtilis, which gave ZOI of 15 mm and 20 mm, respectively, compared to tetracycline 20 mm and 18 mmDisc diffusion methodArabuko-Sokoke, forest in Malindi district, Kilifi CountyNot reported[105]Cinnamomum cassia Presl. (Lauraceae)Food poisoning, flavoringFruitsThe ethanolic extract of cinnamon was effective againstE. coli by with a ZOI of 27 mm and MIC of 0.12 μg/mlAgar well diffusion method/broth dilutionKenyatta UniversityNot reported[66]Bidens pilosa L. (Asteraceae)Stomach upsetsLeavesThe stem bark DMSO extract exhibited ZOI of 12 ± 0.1 mm compared to Flucloxacillin 14 ± 0.7 mm againstE. coliAgar well diffusion methodNarokExtract showed no adverse effects in mice and chickens at a dose of 5% or less of food[38, 106]Acacia lahai Stead. & HochsLei Benth (Fabaceae)Skin eruptionsBarksThe methanol extract (200 mg/ml) had a ZOI of 15.00 ± 0.00 mm againstB. cereus compared to Gentamicin (40 ug/ml) 15.83 ± 0.76 mm, ZOI of 11.33 ± 0.29 mm against MRSA compared to Gentamicin (40 μg/ml) 15.67 ± 1.04 mm. The acetone extract (200 mg/ml) had a ZOI of 10.33 ± 0.58 mm against P. aeruginosa compared to Gentamicin (40 μg/ml) 15.12 ± 0.63 mmDisk diffusion methodMosonik hill, Sotik Sub-county, Bomet CountyNot reported[107]Bridelia micrantha (Hochst.) Baill. (Euphorbiaceae)Stomachache, diarrhea in childrenLeavesThe methanol extract 100 mg/mL exhibited ZOI of 19 mm and 13 mm againstS. aureus and S. typhiDisc diffusion methodKilifi DistrictThe extract has a wide margin of safety for oral use at doses below 2000 mg/kg[49, 108]Grewia plagiophylla K. Schum. (Malvaceae)Dysentery, typhoidLeavesThe methanol extract 100 mg/mL exhibited ZOI of 20 mm and 17 mm againstS. aureus and S. typhiDisc diffusion methodKilifi DistrictNot reported[49]Vigna subterranea (L.) (Fabaceae)Traditional foodNutsThe MIC values for organic extract ranged fromE. coli—7.72 ± 0.35 μg/ml, S. aureus—12.5 ± 0.32 μg/ml, and P. aeruginosa—7.95 ± 0.10 μg/ml. At 100 μg/ml, E. coli, S. aureus, and P. aeruginosa showed a ZOI of 27 ± 0.74 mm, 25.3 ± 0.40 mm, and 25.1 ± 0.24 mm, respectively, compared to those of ceftriaxone, which were 37.0 ± 0.5, 41.3 ± 0.9, and 42.3 ± 0.9 mmDisc diffusion methodBungoma countyNot reported[109]Citrus limon (L.) Osbeck (Rutaceae)Sore throat, chest painRhizomesLemon juice inhibited the growth ofS. typhi with a ZOI of 11.0 mm and ZOI 11. 0 mm against P. aeruginosa compared to chloramphenicol 20.0 ± 0.0 mmDisc diffusion testGithurai market, NairobiThe juice is considered non–toxic and extremely safe for consumption even at above 80% concentration[64, 110]Ziziphus abyssinica Hochst (Rhamnaceae)Meat preservativeFruit pasteThe methanolic extract gave ZOI of 24 mm, and 20 mm againstE. coli and S. aureus, respectively, compared to chloramphenicol 16 mm and 18Disc diffusion testChepararia and Kongelai subcounties of West Pokot countyThe acute toxicity (LD50) of the leaf extracts was found to be greater than 5000 mg/kg and is considered relatively safe for use[94, 111]Mentha spicata L. (Lamiaceae)Common coldLeavesThe ZOI inS. aureus varied from 16 ± 0.02 mm in replicate 2 to 18 ± 0.01 mm in replicate 1, E. coli (13 ± 0.02 mm in replicate 2 to 15 ± 0.02 mm in replicate 1), and in K. pneumoniae (20 ± 0.01 mm in replicate 3 to 20 ± 0.02 mm in replicates 1 and 2)Agar well diffusion methodEgerton UniversityThe LC50 value was 1701 g/ml in brine shrimp lethality assay, indicating that the plant extract is nontoxic[112, 113]Indigofera lupatana Baker F. (Leguminosae)Cough, diarrhea, and gonorrheaRootsThe organic extract showed a highest activity againstB. subtilis (28.5 ± 0.3 mm), S. aureus (22.6 ± 1.0 mm), B. cereus (22.0 ± 0.3 mm), E. coli (21.7 ± 0.7 mm), P. aeruginosa (21.5 ± 0.9 mm), S. typhimurium (17.3 ± 0.3 mm), K. pneumoniae (15.3 ± 0.4 mm), and P. mirabilis (12.3 ± 0.5 mm)Disc diffusion assayMbeere District, in the Eastern Province of KenyaThe extract had an LC50 value greater than 1000 μg/ml which is an indication that they are all nontoxic[114]Momordica charantia L. (Cucurbitaceae)DiabetesFruitThe extracts exhibited a ZOI of 10.66 mm againstS. aureus compared to amoxicillin 21.03 mm and MIC and MBC of 37.5 mg/mL , ZOI of 9.33 mm MIC and MBC of 37.5 mg/mL against P. aeruginosaAgar disc diffusion (DD) method/broth dilution techniqueLake Victoria RegionThe LD50 of the ethanolic extract is considered safe to be consumed below 2000 mg/kg[36, 115]Blighia unijugata Bak (Sapindaceae)Tonic, anthelminthicRoots, pods, and leavesThe methanol and chloroform extracts together with the pure compound, friedelin, were active againstS. aureus with zones of inhibition of 18.0, 22.0, and 10.0 mm, respectively. Gentamicin (10 μg/rnl) had a ZOI of 26.0 mm against S. aureusDisc diffusion assayKiangwachi, Kirinyaga DistrictThe extract has the LD50 of 5.628 ± 0.29 g/kg b. wt[116, 117]Moringa oleifera Lam. (Moringaceae)Antioxidant, spasmsSeeds, stemThe water extracts showed activity againstS. aureus with MIC values ranging from 6.25 to 50 mg/mlBroth microdilution techniqueMoringa oleifera is genotoxic at supra-supplementation levels of 3000 mg/kg b.wt. However, intake is safe at levels ≤ 1000 mg /kg b.wt[118, 119]Maesa lanceolata Forssk (Myrsinaceae)Bacterial infectionsRoots, leaves, and stem barkThe stem bark extract exhibited a ZOI of 20.70 ± 0.6 mm againstS. aureus compared to gentamycin (1.0 μg/disc), 14.30 ± 0.6 and ZOI of 13.00 ± 1.0 mm against P. aeruginosa compared to gentamycin (1.0 μg/disc) 16.00 ± 1.0 mmDisc diffusion methodElgeyo Marakwet countyDCM extracts of stem bark and leaves were lowly toxic. No mortality was observed within 24 hours[120]Satureja biflora Buch-Ham (Lamiaceae)AntimicrobialLeavesThe essential oil exhibited a ZOI of (31 ± 0.5 mm), MIC 125 mg/mL againstS. typhi and (24 ± 02 mm), 93.8 mg/mL against S. aureus compared to chloramphenicol 10 ± 1.0 mm, MIC 25 mg/mL against S. typhi and 24 ± 1.0 mm, MIC 31 mg/mL against S. aureusAgar disc diffusion method/broth dilutionBotanical garden of Egerton universityNot reported[86]Lannea schweinfurthii (Engl.) Engl (Anacardiaceae)Bacterial infectionsAn isolated compound epicatechin had zone diameter of growth inhibition of crude extract was (15.05 mm) againstS. aureus and (14.02 mm) against B. subtilis compared to tetraycline 18.02 mm against S. aureus and B. subtilisDisc diffusion methodBondo, Siaya CountyNot reported[121]Annanus comosus (Bromeliaceae)IndigestionFruitsThe MIC of nanoencapsulated bromelain againstEnterobacter spp., Citrobacter spp., Serratia spp., and coagulase-negative Staphylococci was 25 μg/ml, while that of E. coli was 50 μg/ml. The MIC of nanoencapsulated bromelain against Klebsiella spp. and S. aureus was 200 μg/ml. Bromelain was effective against gram-positive and gram-negative bacteria. Streptomycin had a MIC of 22.2 μg/mlAgar well diffusion method/broth microdilution methodThika TownLeaf extract is nontoxic[122, 123]Helichrysum forskahlii (Asteraceae)CoughWhole plantH. forskahlii had the highest inhibition zone against MRSA of 19.5 and 18.5 mm in agar well and agar disk diffusion respectively. Chloramphenicol had ZOI 24 mmDisc diffusion method/agar well diffusion methodLosho, Narok CountyThe brine shrimp lethality test found the plant to be highly toxic with a lethal concentration of 0.009 mg/ml[124]Citrullus lanatus (Cucurbitaceae)FoodFruitThe MIC value of the nanoparticles was 45.00 ± 0.01 mg/ml forS. typhi and 38.50 ± 0.00 mg/ml for E.coli, while the MBC value was 60.00 ± 0.05 mg/ml for S. typhi and 50.00 ± 0.00 mg/ml for E. coliDisc diffusion methodWakulima Market, Muthurwa Market, and Githurai Market within Nairobi countyLD50 of EECLS was greater than 2000 mg/kg BW and the no observed adverse effect level (NOAEL) of EECLS was at a dose of 1000 mg/kg in rats[125, 126]Hyptis spicigera (Lamiaceae)Stomach ache, pulmonary troublesLeavesThe methanolic extract (1 g/ml) had a ZOI of 19.3 mm and 19.0 mm againstS. aureus and S. typhi, respectively, compared to amoxicillin 23.0 mm and 21.3 mm. The methanolic extract had an MIC of 37.5 mg/ml against S. aureus and S. typhi compared to 18.75 mg/ml for amoxicillinAgar disc diffusion methodMarera Region in Central ProvinceNot reported[79]Crotalaria quartiniana (Fabaceae)DiarrhoeaLeavesThe methanol extract (1 g/ml) had a ZOI of 21.0 mm, 19.3, 21.0, 20.7, 18.7, and 20.7 againstS. aureus, S. typhi, E. coli, P. aeruginosa, and K. pneumoniae, respectively, compared to amoxicillin 23.0, 21.3, 20.2, 17.3, and 17. 66 and an MIC of 37.5 mg/ml against S. aureus, S. typhi, E. coli, P. aeruginosa, and K. pneumoniae compared to 18.75 mg/ml for amoxicillinAgar disc diffusion method/broth dilutionTatu region in central provinceNot reported[79]Eurphobia hirtaDiarrhea, asthmaWhole plantThe methanol extract (1 g/ml) had a ZOI of 21.0 mm, 18.66, 19.66, 16.33, 16.33, and 14.33 againstS. aureus, S. typhi, E. coli, P. aeruginosa, and K. pneumoniae, respectively, compared to amoxicillin 23.0, 21.3, 20.2, 17.3, and 17. 66 and MIC of 18.75 mg/ml against S. aureus, S. typhi, E. coli, P. aeruginosa, and K. pneumoniae compared to 18.75 mg/ml for amoxicillinAgar disc diffusion method/broth dilutionTwiga Region in Central ProvinceThe LD50 of this plant is more than 5000  mg/kg[79, 127]Lippia kituiensis (Verbenaceae)Diarrhea, chest problemsLeavesThe methanol extract (1 g/ml) had a ZOI of 23.3 mm and 17.6 mm, againstS. aureus and P. aeruginosa, respectively, compared to amoxicillin 23.0, and 17.3. The methanol extract (1 g/ml) had an MIC of 37.5 mg/ml against S. aureusAgar disc diffusion method/broth dilutionMarera Region in Central ProvinceNot reported[79]Eurphobia scarlatina (Euphorbiaceae)Stomach ache, common cold, TBStemThe extract exhibited zero GUs at 0.5 mg/ml againstM. kansasii and M. tuberculosis compared to Isoniazid that had zero GUs at 0.5 mg/mlBACTEC mgIT™ 960 systemVarious conservancies in SamburuNot reported[36]Acacia horrida. (Fabaceae)Diarrhoea, TBBarksA. horrida had appreciable inhibition (257 GUs) against M. tuberculosis (198 GUs) at the concentration of 0.5 mg/ml compared to Isoniazid that had zero GUs at 0.5 mg/mBACTEC mgIT™ 960 systemVarious conservancies in SamburuNot reported[36]Phyllanthus urinaria Linn (Phyllanthaceae)Dysentery, diarrhea, stomach acheLeaves, rootsMIC and MBC of 18.75 mg/ml and 37.50 mg/ml, respectively, against E. coliBroth dilutionTransmara WestNot reported[51]Rhamnus prinoides L’He’r (Rhamnaceae)Typhoid, stomach acheStem, rootsThe extract inhibitedE. coli with MIC and MBC of 9.37 mg/mlBroth dilutionTransmara westRhamnus prinoides was nontoxic to brine shrimp[51, 128]Tetradenia riparia (Lamiaceae)Respiratory problems, stomach ache, diarrhea, antisepticRoots, stemThe organic extract inhibitedS. epidermidis with a ZOI of 27.67 ± 0.333 mm compared to penicillin 26.67 ± 0.333 and E. coli with a ZOI of 13.33 ± 0.333 mm compared to penicillin 31.33 ± 0.333Disc diffusionNatural forest around the University of Eastern Africa, BaratonToxic effect recorded for root and fruit extracts but not for leaf or stem extracts. In mice at dose 1.0 g/kg[61, 129]Kigelia africana Lam and Benth (Bignoniaceae)Laxative, gonorrhea, tuberculosis, diarrheaFruits, barksThe methanolic extract had a ZOI of 11.3 mm compared to (19 mm) gentamycin againstS. aureus and ZOI (10 mm) compared to (9 mm) chloramphenicol against MRSA. The MIC values of acetone extracts were 6.25 mg/ml against MRSADisc diffusionKaptumo Division, NandiNot reported[130]Conyza sumatrensis (Asteraceae)PimplesLeaves/rootsThe methanolic extract had a ZOI of 26.85 mm compared to (13.67 mm) chloramphenicol againstE. coli and ZOI (27 mm) compared to (15.8 mm) chloramphenicol against B. pumulusAgar diffusion assay methodRarieda, Bondo district, of Nyanza province in KenyaExperiments indicate the methanol extract to be safe even at high and repeated doses in pre-clinical studies[131, 132]Piliostigma thonningii (Fabaceae)Cough, colds, chest pains, stomachache, woundsStem barkThe methanolic extract had MIC (3.125 mg/ml) compared to (>1 mg/ml for antibiotic standards) againstS. aureus, MIC (31.25 mg/ml) compared to (>1 mg/ml for antibiotic standards) against and E. coli and MIC (15.625 mg/ml) against P. aeruginosaBroth dilution methodMeru central districtPlant extracts had LD50 values >2000 mg/kg bw and were hence deemed to be nontoxic[40, 133]Erythrina abyssinica (Fabaceae)Anthrax, syphilis, gonorrhea, burns, body swellingsRoot barkThe methanolic extract had an MIC of 3.125 mg/ml compared to >1 mg/ml for antibiotic standards againstS. aureus, MIC (250 mg/ml) compared to (>1 mg/ml for antibiotic standards) against and E. coli and MIC (125 mg/ml) against P. aeruginosaTest tube methodMeru Central DistrictThe extracts are not toxic to the human cell[40, 134]Rynchosia minima DC. (Fabaceae)SwellingRootsThe methanolic extract had a ZOI of 11.5 mm compared to 15 mm gentamycin againstS. aureusDisk diffusion techniqueCentral KenyaNot reported[135]Entada abysinnica (Fabaceae)Gastrointestinal bacterial infections, bronchitisLeavesThe methanol leaf extract (100 mg/ml) had ZOI (10. 33 mm) compared to (16.0 mm) zeftazidime againstS. typhiDisk diffusion techniqueBondo (Sakwa) in western KenyaNot reported[36]Withania somnifera (Solanaceae)Microbial infections, cholesterol-loweringLeaves, rootsThe dichloromethane extract (100 mg/ml) had a ZOI of 16.0 mm compared to (18.0 mm) chloramphenicol againstS. aureus, ZOI (14.0 mm) compared to (24.0 mm) chloramphenicol against MRSA and MIC of 6.25 mg/ml against S. aureus and 12.5 mg/ml against MRSADisc diffusion test/broth dilutionNgong forestThe extract is relatively safe for use even in dose levels exceeding 200μg/ml[59]Thalictrum rhynchocarpum (Ranunculaceae)Stomach discomfort and bacterial infectionsRoots, barkThe root extract had an MIC of 21.5 mg/ml againstB. subtilis compared to ciprofloxacin 21.5 mg/mlBroth dilutionNgong ForestNot reported[136]Hugonia castaneifolia (Linaceae)Intestinal wormsRootsThe dichloromethane stem bark extract (100 mg/ml) was active againstS. aureus (MIC 0.0008 mg/ml, respectively). Hexane stem bark extracts were active against S. aureus at 0.0031 mg/ml gentamicin and had an MIC of 0.5 mg/mlBroth dilutionCoast Province of KenyaNot reported[29]Tabernaemontana stapfiana Britten (Apocynaceae)STIs and respiratory-tract infectionsStem bark, root bark, fruits and leavesThe ethanolic root extract (100 mg/ml) had a ZOI of 18.0 mm compared to (22.0 mm) chloramphenicol against MRSA and multiple drug-resistantS. aureus (MDRS) and MIC of 3.9 μg/mlDisc diffusion test/broth dilutionKaptagat Forest in Keiyo DistrictNot reported[137]Rhus vulgaris (Anacardiaceae)GIT disordersLeaves, barkThe methanol extract ofRhus vulgaris showed significant antimicrobial activity against MRSA (12.00 ± 0.00 mm; MIC of 0.391 mg/ml; minimum bactericidal concentration of 1.563 mg/ml). Compared to (6.00 ± 0.00 mm) sulfamethoxazole/trimethoprim (23.7:1.25 μg). The methanol extract showed significant antimicrobial activity against S. aureus (19.50 ± 0.71 mm; MIC of 0.391 mg/ml; compared to (24.19 ± 3.60 mm) sulfamethoxazole/trimethoprim (23.7:1.25 μg)Disc diffusion assay/minimum inhibitory concentration assayMwala Sub-County, Machakos CountyThere were no observable adverse effects from oral administration of the extracts (acute oral toxicity testing) at concentrations of 50 mg/kg, 300 mg/kg, and 2000 mg/kg[138]Zanthoxylum paracanthum Kokwaro (Rutaceae)DiarrhoeaRoot barkThe CH2Cl2/CH3OH (1 : 1) extract from the root bark had MIC values of 3.91, 1.95, 0.98, and 7.81 μg/mL, against MRSA, E. coli, S. aureus compared to 0.98, 0.49, and 0.98 μg/ml of omacillinMinimum inhibitory concentration assayMrima Hills, Kwale County in KenyaNot reported[139]Centella asiatica (Apiaceae)Bacterial infections, diarrhea, skin lesions, psoriasis, keloidsLeavesOrganic crude extract of the leaf showed the highest activity ZOI of 16.33 ± 0.33 mm againstE. coli compared to tetracycline 26.67 ± 0.33 mmDisc diffusion methodKisii CountyThe lethal dose and no observable adverse effect level were 2000 mg/kg and 1000 mg/kg[32, 140]Aloe vera (Asphodelaceae)Blood purifier, malaria, skin disease, diabetesLeavesThe organic extract exhibited a ZOI of 17 ± 2 − 19 ± 2 mm againstS. aureus, (18 ± 2 − 20 ± 1 mm against B. subtilis), (17 ± 1 − 19 ± 3 mm) against K. pneumoniae, (16 ± 1 − 20 ± 3 mm) against E. coliAgar diffusion methodDepartment of biological sciences, Egerton universityNot reported[141]Aloe volkensii (Asphodelaceae)Laxative, burns, wounds and soresLeavesThe organic extract exhibited activity againstS. aureus (19 ± 1 − 20 ± 2 mm), B. subtilis (17 ± 2 − 21 ± 3 mm), K. pneumoniae (18 ± 2 − 19 ± 1 mm), E. coli (18 ± 2 − 19 ± 3 mmAgar diffusion methodDepartment of Biological Sciences, Egerton UniversityNot reported[141]Senna spectabilis (Fabaceae)LaxativesLeaves, podsThe organic leaf extract (100 mg/ml) had a ZOI of 9.6 ± 0.6 compared to chloramphenicol (11.7 ± 2.3) againstS. typhiAgar diffusion methodMbeere North District, Embu CountyNot reported[142]Maytenus putterlickioides (Celastraceae)Malaria, emmenagogue, aphrodisiacRootsThe methanol root extract (100 mg/ml) had a ZOI of 9.2 ± 1.1 compared to chloramphenicol (11.7 ± 2.3) againstS. typhiAgar diffusion methodMbeere North District, Embu countyNot reported[142]Olinia usambarensis (Oliniaceae)Malaria, abscess, cough, measlesBark, roots, leavesThe methanol leaf extract (100 mg/ml) had ZOI (12.2 ± 0.8) compared to chloramphenicol (11.7 ± 2.3) againstS. typhiAgar diffusion methodMbeere North District, Embu CountyNot reported[142]Crotalaria goodformis Vatke. (Fabaceae)The aqueous extract (1 g/ml) had a ZOI of 14.8 ± 0.2 mm compared to (18.0 ± 0.1) streptomycin (25μg/ml) against S. aureusDisk diffusion methodMbeere, and Embu-Eastern ProvinceNot reported[48]Prosopis juliflora (Sw.) DC (Fabaceae)Open wounds and dermatological ailments.LeavesThe ethanolic leaf extract (100 mg/ml) had a ZOI of 20.00 ± 1.00 mm compared to (19.0) erythromycin (15μg/ml) and (30.0 mm) chloramphenicol (30 μg/ml) against E. coli, ZOI (15.33 ± 0.58 mm) compared to (11.0) erythromycin (15 μg/ml) and (22.0 mm) chloramphenicol (30 μg/ml) against P. aeruginosaDisk diffusion methodEndao, Marigat District, in Baringo CountyThe pods are toxic, mainly for cattle and goats, and have piperidine alkaloids and can cause neurotoxicity[143, 144]Osyris abyssinica (Santalaceae)Dysentery, typhoidRootsThe aqueous root extract (1 g/ml) had ZOI (15.2 ± 0.7 mm) compared to (18.0 ± 0.1) streptomycin (25μg/ml) against S. aureus, ZOI (14.8 ± 0.3 mm) compared to (16.0 ± 0.2) streptomycin (25 μg/ml) against E. coli, ZOI (15.5 ± 0.5 mm) compared to (15.0 ± 0.3 mm) streptomycin 25 μg/ml against B. subtilisDisk diffusion methodMbeere, and Embu-eastern provinceNot reported[48]Abrus precatorius (Fabaceae)Gonorrhea, coughs in childrenLeaves, rootsThe aqueous leaf extract (1 g/ml) had a ZOI of 15.7 ± 0.5 mm compared to (18.0 ± 0.1) streptomycin (25μg/ml) against S. aureus. The aqueous bark extract (1 g/ml) had a ZOI of 7.2 ± 0.8 mm compared to (16.0 ± 0.2) streptomycin (25 μg/ml) against E. coli, ZOI (15.5 ± 0.5 mm) compared to (10.7 ± 1.2 mm) streptomycin 25 μg/ml against B. subtilisDisk diffusion methodMbeere, and Embu-Eastern ProvinceIt contains abrin, a toxalbumin that inhibits protein synthesis causing cell death. especially seeds[48, 145]Ormocarpum trichocarpum (Fabaceae)Bone settingRootsThe methanol extract (1 g/ml) had a ZOI of 15.5 mm compared to (26.0 mm) gentamycin (10μg/ml) against B. subtilisDisk diffusion methodKisii SouthNot reported[30]Psidium guajava (Myrtaceae)Wounds, ulcers, choleraLeavesThe methanol extracts (1 g/ml) had a ZOI of 19.7 mm compared to gentamycin (10μg/ml) against S. aureus, ZOI (16.0 mm) compared to gentamycin (10 μg/ml) 19 mm against E. coli and, ZOI (16 mm) compared to 10 μg/ml gentamycin (17 mm) against P. aeruginosaAgar well diffusionBomet DistrictThe median lethal dose (LD50) of bark extract is greater than 5000  mg/kg body weight[46, 145]Cyathula polycephala (Amaranthaceae)Diabetes, skin infections, pneumoniaStem barksThe methanol extract 100 mg/ml had a ZOI of 14.2 mm compared to 30μg/ml gentamycin (19.0 mm) against S. aureus, ZOI (16.0 mm) compared to 30 μg/ml gentamycin (9.0 mm) against MRSA, ZOI (10.0 mm) compared to 30 μg/ml gentamycin (21.0 mm) against P. aeruginosaDisk diffusion methodBomet DistrictThe methanol extract was very safe with a CC50 of 100%, while water extract were toxic with CC50 of 23.75% and 31.56% as compared to the positive control Chloroquine with CC50 of 25.28 and 51.94% at concentration 1000 and 100 mg mL-1[29]Blumea axillaris (Lam.) DC. (Asteraceae)Skin diseaseAerial partsMethanol extracts had a ZOI 16.41 ± 0.31 compared to chloramphenicol (21.7 ± 0.11) againstS. aureusAgar well diffusionVihiga County, Western KenyaNone reported[45]Chamaecrista mimosoides (L.) Greene (Fabaceae)Respiratory system disorders, dysenteryAerial parts, rootsThe aqueous extracts had a ZOI 30.00 ± 1.46 compared to chloramphenicol (21.7 ± 0.11) againstS. aureusAgar well diffusionVihiga County, Western KenyaNot reported[45]Lantana trifolia L. (Verbenaceae)Cough and common coldsAerial partsThe methanol extracts had a ZOI of 20.59 ± 0.92 compared to chloramphenicol (21.7 ± 0.11) againstS. aureusAgar well diffusionVihiga County, Western KenyaThe ethanol extracts of Lantana trifolia (LC50 32.3 μg/ml exhibited mild toxicity and are safe for short-term use (Moshi et al., 2010)[45]Terminalia kilimandscharica Engl. (Combretaceae)Cough, sexually transmitted diseasesBarksThe methanolic bark extract had a MIC of 25, 15.6, 37.5, and 150 mg/mL againstS. aureus B. cereus, P. aeruginosa, and E. coli, respectively, compared to that of 0, 0, 0.25, 0.25 mg/mL of streptomycin against S. aureus B. cereus, P. aeruginosa. and E. coli, respectively, and benzylpenicillin 0.6 and 0.6 against S. aureus and B. cereus, respectivelyBroth dilutionMachakos and KituiThe methanolic bark extracts had an LC50 of <1000 μg/mL, which is considered relatively nontoxic[39]Pentas lanceolata (Rubiaceae)Genital and oral thrushRootsThe ethyl acetate extract (100 mg/ml) had a ZOI of (10.96 ± 0.08 mm) compared to gentamycin (23.88 ± 0.01 mm) againstK. pneumoniae, ZOI of (12.08 ± 0.26 mm) compared to gentamycin (23.88 ± 0.01 mm) against Escherichia coli and ZOI of (11.39 ± 0.6 mm) compared to gentamycin (25.9 ± 0.01 mm) against S. aureusAgar well diffusionMagadi, Kajiado District of KenyaNot reported[44]Sericocomposis hildebrandtii Schinz (Amaranthaceae)PurgativeRootsThe ethyl acetate root extract (100 mg/ml) had a ZOI of 11.28 ± 0.09 mm compared to gentamycin (0.1μg/ml), (23.88 ± 0.01 mm) against K. pneumoniae, ZOI of (10.33 ± 0.06 mm) compared to gentamycin (0.1 μg/ml) (23.88 ± 0.01) against E. coli, and ZOI of (10.66 ± 0.18) compared to gentamycin (0.1 μg/ml) (25.9 ± 0.01) against S. aureusAgar well diffusionMagadi, Kajiado District of KenyaNot reported[44]Combretum molle R.Br. ex G.Don (Combretaceae)Tooth brush, stomach ache, and dysenteryStem barkThe ethanolic stem bark extract (0.5 mg) exhibited ZOI (mm) of 7.6 ± 0.24 againstP. aeruginosa, 15.4 ± 0.3 against E. coli, and 2.2 ± 0.4 against S. aureus compared to Augmentin 8.0 ± 0.02 against P. aeruginosa, 19.0 ± 0.03 against E. coli and 17.0 ± 0.02 against S. aureusDisc diffusion methodMwingi District in Kitui CountyFor the acute toxicity test, no death and signs of poisoning were observed in the treated groups. In the subacute study, LD50 in the rats after intraperitoneal administration was 700 mg/kg[76, 146]Combretum illairii (Combretaceae)Roots, stems, leavesThe methanol leaf extract (100 mg/ml) had ZOI of 15.60 mm and 17.00 mm againstS. aureus and P. aeruginosa, respectively, against gentamycin (30 μg/ml) 25.3 mm and 18 mmDisc diffusion assayKilifi DistrictThe stem bark extracts had neither cytotoxicity nor brine shrimp lethality. plant extracts[29]Combretuam tanaense (Combretaceae)Skin infections, wounds dressings and ointmentsRootsThe methanol root extract (100 mg/ml) had a ZOI of 11.50 ± 0.5 mm compared to ciprofloxacin (0.32μg/ ml) 14.75 ± 0.25 mm against S. aureus and ZOI of 12.25 ± 0.25 mm compared to ciprofloxacin (0.32 μg/ ml) 16.00 ± 0.00 mm against K. pneumoniaeAgar well diffusion assayMount Kenya University Botanical Garden, ThikaNot reported[104]Vernonia brachycalyx (Asteraceae)Antimalarial, emeticStem, leavesThe ethanol extract had a ZOI of 9.5 ± 1.2 mm againstS. pneumoniae compared to 8.2 ± 0.6 (erythromycin) 7.2 ± 0.5 (gentamycin 15 μg)Disk diffusion methodEastern KenyaAn isolated compound (16,17-dihydrobrachycalyxolide) displayed high toxicity against human lymphocytes[18]Vernonia amygdalina (Asteraceae)Stomach discomfort and bacterial infectionsLeavesThe methanol leaf extract (1 g/ml) exhibited a ZOI 17.0 mm compared to gentamycin (10μg/ml) 19 mm against S. aureusAgar well diffusionBomet DistrictThe extract had an LD50 of 288.5 mg/kg body weight. It has relative toxicity [147][46]Vernonia glabra (Steetz) Oliv. & Hiern (Asteraceae)Gastrointestinal problems , snake bitesLeaves, rootsThe dichloromethane/methanol leaf extract (1 g/ml) exhibited a ZOI of 1.85 cm againstS. aureus compared to streptomycin with a ZOI of 1.30 cm. dichloromethane/methanol extract of flower showed significant activity only against S. aureus, with the lowest MIC of 1.5625 mg/100 μl, compared to streptomycin with a MIC of 6.25 mg/100 μlDisc diffusionMachakosNot reported[27]Vernonia adoensis (Asteraceae)Oral healthStem barkThe methanol stem bark extract (100 mg/ml) exhibited a ZOI of 13.00 ± 0.577 mm againstE. aerogenes, 11.00 ± 0.577 mm against S. pyogenes, 9.67 ± 0.333 mm against S. epidermidis, and 9.00 ± 0.577 mm against E. faecalis. The acetone stem bark extract (100 mg/ml) exhibited a ZOI of 16.00 ± 0.577 mm against E. aerogenes, 11.33 ± 0.882 mm against S. epidermidis, and 10.00 ± 0.577 mm against S. faecalis. Penicillin (100 mg/ml) exhibited a ZOI of 38.00 ± 0.577 mm against E. faecalis, 43.33 ± 0.882 against S. pyogenes, 19.33 ± 0.333 against S. epidermidis, and 36.33 ± 0.882 against E. aerogenesDisc diffusion methodNatural forests around the University of Eastern Africa, Baraton, Nandi CountyNot reported[148]Vernonia hymenolepis (Asteraceae)Infections, toothacheLeavesThe MBC and MIC values of aqueous leaf extract was 400 mg/ml againstS. aureus, while the DCM/methanol leaf extract had MIC and MBC of 400 mg/ml against P. aeruginosa and E. coli, and MIC of 100 mg/ml against S. aureus. Amoxicillin had MIC and MBC of 3.125 mg/ml and 6.25 mg/ml against E. coli, respectivelyBroth dilutionTrans Nzoia CountyNot reported[149]Aloe secundiflora (5), Toddalia asiatica (5), Senna didymobotrya (5), Warbugia ugandensis (5), Tithonia diversifolia (4), Fuerstia africana (4), Olea africana (4), and Harrisonia abyssinica (4) were the plants frequently evaluated within Kenya. The plants with the strongest antimicrobial activities were Toddalia asiatica, Hagenia abyssinica, Ocimum gratissimum, Harrisonia abyssinica, Conyza sumatrensis, Senna didymobotrya, Aloe secundiflora, Olea Africana, Vernonia glabra, Camellia sinensis, Tetradenia riparia, and Tarmarindus indica as they exhibited high mean inhibition zone values or low minimum inhibitory concentration (MIC) values. The zones of inhibition (ZOIs) were interpreted as low activity (1 mm–6 mm), moderate activity (7 mm–10 mm), high activity (11 mm–15 mm), and very high activity (>16 mm) (Zaidan et al., 2005). The frequently analyzed plant parts were leaves (37%), bark/stem bark (47%), fruits/seeds (5), pods (1%), and roots (24%). Water and methanol were the most used solvents for plant extract preparation, whereas ethanol and dichloromethane were the least utilized solvents used (Table 1).The reported medicinal plants were commonly used in the treatment of STIs, respiratory diseases, diarrhea, and oral infections (Table1). (Figure 1).Figure 1
Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement of search results.


## 4. Discussion

Plants generally accumulate diverse bioactive compounds in varying concentrations in the different parts of a plant, and this eventually affects the efficacy of medicinal plants. The leaves (37%), bark/stem bark (47%), and roots (24%) were the most utilized plant parts against bacterial infections. The variances in their antimicrobial activities could be due to the synergistic or antagonistic actions of various secondary metabolites present [60].


### 4.1. Nutraceuticals

From the review, several common foods/spices are reported to have potential antibacterial benefits. For example, green tea (Camellia sinensis) that is often famed for its antioxidant activity, exhibited good antibacterial activity zone of inhibition (ZOI) of 21.3 Ł} 0.33mm against E.coli and a ZOI of 22.3 ± 0.50 mm against S. aureus compared to gentamicin 22.3 Ł} 0.50 mm (against E. coli) and ZOI 23.7 Ł} 0.33 mm (against S. aureus) at a concentration of 0.1 mg/ml [67]. The aqueous crude green tea extracts at a concentration of 400 mg/ml exhibited ZOI of 20 ± 0.0 mm which was similar to that of streptomycin against S. aureus. The extract also displayed a ZOI of 18 ± 0.0 mm against E. coli compared to ZOI of 10 ± 0.0 mm of streptomycin against E. coli 20 ± 0.0 mm, ZOI of 18 ± 0.0 mm, and MIC 200 mg/ml against E. coli compared to streptomycin 10 ± 0.0 mm [69]. The Bambara nut (Vigna subterranea) had an MIC value of 7.72 ± 0.35 μg/ml for E. coli, 12.5 ± 0.32 μg/ml for S. aureus and 7.95 ± 0.10 μg/ml for P. aeruginosa at 100 μg/ml, and showed zone of inhibition of 27 ± 0.74 mm, 25.3 ± 0.40 mm, and 25.1 ± 0.24 mm E. coli, S. aureus, and P. aeruginosa, respectively [109].


### 4.2. Complementary Medicine

As has been shown in previous ethnomedical surveys by Omwenga et al., traditional medicine is widely practiced in Kenya and is culturally acceptable. It is estimated that about 75% population in Kenya seeks health care among traditional healers [8–10, 150]. In certain instances, people utilize both traditional and modern medicine simultaneously. Njoroge and Kibunga noted that herbal products were used as complementary therapy in the management of diarrhea by residents in Thika, Kenya [151]. The lack of enquiry about Traditional Complementary and Alternative Medicine (TCAM) use and the conventional healthcare providers’ negative attitude towards TCAM were cited as some of the reasons why patients fail to reveal their TCAM use [152].The regulatory framework for the practice of traditional medicine in Kenya is still underway [153], but several crude drugs or formulated herbal products with reported antibacterial activity are already available in the Kenyan market, for example, the Lifebuoy germ protection antibacterial herbal hand and body soap and the Dettol herbal bar soap. Skin care products (soaps and lotions) formulated from plant extracts (Thevetia peruviana, Tithonia diversifolia, Azadirachta indica, Aloe secundiflora) had antimicrobial properties. Soap made from Tithonia diversifolia plant extract was the most effective against E. coli, while Azadirachta indica soap was the most effective against C. albicans. T. diversifolia soap exhibited the highest activity against E. coli [154].The ethanolic extract ofE. divinorum root bark had a MIC of 25, 50, and 25 μg/ml for Streptococcus pyogenes, Staphylococcus aureus, and Escherichia coli, respectively (Table 1). A herbal toothpaste formulated with the ethanol extract of E. divinorum root bark had a higher antimicrobial activity against the tested microorganisms compared to Colgate herbal toothpaste formulated with fluoride [77]. Also, the formulation containing the aqueous extracts of T. asiatica (50 mg/ml) stem bark exhibited pronounced antimicrobial activity as indicated by zone of inhibition diameters of 24 mm (MRSA) and 22 mm (M. gypseum) compared to 22 mm and 14 mm, respectively, by the commercial hand wash (50 mg/ml). In the model hand washes efficacy experiment, the formulated herbal detergent attained a 78.8% reduction of pathogenic load as compared to 67.9% reduction with the commercial hand wash [37].Unfortunately, despite the surge in the consumption herbal products and the limited number of standardized herbal products in the Kenyan market, the pharmacovigilance for herbal medicines is nonexistent in Kenya [155]. The increased demand for herbal products has resulted in the market being flooded with adulterated products and false herbal claims on the products’ labels for marketing purposes. For instance, 50% of the investigated products by Ngari et al. [75] lacked antimicrobial activity against test bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus subtilis, Candida albicans, Escherichia coli, Streptococcus mutans, Enterococcus faecalis, and Lactobacillus acidophilus). The evaluation of herbal suspensions (used in the management of oral health in Nairobi County, Kenya) by Ngari et al. [75] reported a lack of detectable phytochemicals in the suspensions and noted that this occurrence could be due to very low concentrations of phytochemicals that could not be detected by standard laboratory methods or mineral adulterants might have been used. Studies have demonstrated that antimicrobial properties of natural products can be enhanced by the addition of metal ions [14, 156].


### 4.3. Polyherbalism

The use of herbs as combinations is common practice with many herbal practitioners and aimed at giving better results as compared to single herbs and also treating more than one ailment [157]. Ngari et al. [75] evaluated herbal pastes and suspensions used in the management of oral health in Nairobi County, Kenya, and various products showed significant antimicrobial activity that is comparable to positive control. For example, product HS4 composed of W. ugandensis, M. piperita, and S. aromaticum had ZOI of 33.1 ± 0.85 mm, 20.3 ± 1.71 mm, and 19.3 ± 1.65 mm against E. coli, S. aureus, and P. aeruginosa, respectively, compared to that of co-trimoxazole of 27.5 ± 0.7 mm, 8.5 ± 0.5 mm, and 10 ± 0.0 mm, respectively. Product HS5 composed of Aloe vera gel, W. ugandensis, and W. sominifera had a ZOI of 25.3 ± 0.25 mm, 20.25 ± 1.26 mm, and 21.5 ± 1.71 mm against E. coli, S. aureus, and P. aeruginosa, respectively, compared toco-trimoxazole 27.5 ± 0.7 mm, 8.5 ± 0.5 mm, and 10 ± 0.0 mm, respectively. This biological activity is attributed to the presence of various secondary metabolites in plants [14].Mbuthia et al. evaluated the synergistic properties of water-soluble green and black tea extracts with penicillin G. The antimicrobial results showed a marked increase in the inhibition zone diameters on the combination of green tea extracts with penicillin G. The catechins, theaflavins, and thearubigins are the antimicrobial agents present in tea [67].4 Synergistic inhibition by green tea extracts and penicillin G is due to the presence of dual binding sites on the bacterial surface for antibiotic and tea extract [158].


### 4.4. Bioactivity/Assay Methods

Disc diffusion method was the preferred method to assay for antibacterial activity. A clearing zone of 9 mm or greater for Gram-positive and Gram-negative bacteria was used as the criterion for designating significant antibacterial activity [159]. The in vitro MIC results were classified as described in the study by Pessini et al., 2003: the antimicrobial activity of the extracts that displayed MIC lower than 100 μg/ml was considered very high; 100–500 μg/ml, high; 500–1000 μg/ml, moderate; 1000–4000 μg/ml, low; and anything above this, inactive. The plants with the strongest antimicrobial activities were Toddalia asiatica, Hagenia abyssinica, Ocimum gratissimum, Harrisonia abyssinica, Conyza sumatrensis, Senna didymobotrya, Aloe secundiflora, Olea Africana, Vernonia glabra, Camellia sinensis, Tetradenia riparia, and Tarmarindus indica as they exhibited high mean inhibition zone values or low minimum inhibitory concentration (MIC) values.Several plants exhibited a high activity superior or comparable to the standard antibiotic drugs (Table1); the methanol-dichloromethane extract (100 mg/ml) of Harrisonia abyssinica had a ZOI of 20 ± 1.6 mm compared to gentamycin (ZOI of 18 ± 1.2 mm) against S. aureus and a ZOI of 30. ± 1.7 mm against E. coli compared to gentamycin ZOI of 15.1.3 mm against E. coli [41]. The methanolic extract of Croton macrostachyus exhibited ZOI (23.66 mm) compared to (21.33 mm) amoxicillin against S. aureus and ZOI (18.0 mm) compared to (17.58 mm) amoxicillin against P. aeruginosa. The methanolic extract had an MIC of 37.50 mg/ml compared to 18.75 mg/ml cefpodoxime against S. aureus and 18.75 mg/ml compared to 9.372 mg/ml cefpodoxime against P. aeruginosa [79].Plants such asToddalia asiatica, Hagenia abyssinica, Senna didymobotrya, Aloe secundiflora, and Camellia sinensis displayed good activities; thus, they may be considered for the assessment of in vivo activity and possibly formulated into different consumable forms. Korir et al. recommended that for plants with very low or no activity, bioactivity on all parts of the plants, for example, root, stem bark, and leaves combined ought to be done against a wide variety of pathogenic bacteria in order to conclusively report that a certain plant is inactive [29].


### 4.5. Toxicity

Despite herbal remedies being affordable, their lack of efficacy and safety evaluation is a great impediment to their acceptance into mainstream medicine. The safety assessment of herbal remedies remains a challenge as most of the studies of herbal medicines are directed at the toxicological properties of single plant formulations, yet most herbal preparations, especially those used in traditional medicine, contain multiple herbs [160].From this review, 45% of the plants were relatively safe, 44% of the plants have not been assessed for their safety, and 11% of the plants were reported to have high toxicity (Table1). The plants with very high toxicity can be further explored for the antitumor activity or as insecticides.


### 4.6. Plant Conservation Status

Other thanW. ugandensis and Prunus africana, most of the plants identified in this review are largely available and are not under any serious threat to become extinct. Since most of them are obtained from wild habitats, sustainable use of the reported medicinal plants against bacterial infections is advised as a conservation measure. The cultivation of wild medicinal plants is an important approach to safeguard the herbal industry. Biotechnological techniques such as plant cell or tissue culture, biochemical conversions, and clonal propagation of indigenous medicinal plants are another potential strategy in improving herbal medicine [161].


## 4.1. Nutraceuticals

From the review, several common foods/spices are reported to have potential antibacterial benefits. For example, green tea (Camellia sinensis) that is often famed for its antioxidant activity, exhibited good antibacterial activity zone of inhibition (ZOI) of 21.3 Ł} 0.33mm against E.coli and a ZOI of 22.3 ± 0.50 mm against S. aureus compared to gentamicin 22.3 Ł} 0.50 mm (against E. coli) and ZOI 23.7 Ł} 0.33 mm (against S. aureus) at a concentration of 0.1 mg/ml [67]. The aqueous crude green tea extracts at a concentration of 400 mg/ml exhibited ZOI of 20 ± 0.0 mm which was similar to that of streptomycin against S. aureus. The extract also displayed a ZOI of 18 ± 0.0 mm against E. coli compared to ZOI of 10 ± 0.0 mm of streptomycin against E. coli 20 ± 0.0 mm, ZOI of 18 ± 0.0 mm, and MIC 200 mg/ml against E. coli compared to streptomycin 10 ± 0.0 mm [69]. The Bambara nut (Vigna subterranea) had an MIC value of 7.72 ± 0.35 μg/ml for E. coli, 12.5 ± 0.32 μg/ml for S. aureus and 7.95 ± 0.10 μg/ml for P. aeruginosa at 100 μg/ml, and showed zone of inhibition of 27 ± 0.74 mm, 25.3 ± 0.40 mm, and 25.1 ± 0.24 mm E. coli, S. aureus, and P. aeruginosa, respectively [109].


## 4.2. Complementary Medicine

As has been shown in previous ethnomedical surveys by Omwenga et al., traditional medicine is widely practiced in Kenya and is culturally acceptable. It is estimated that about 75% population in Kenya seeks health care among traditional healers [8–10, 150]. In certain instances, people utilize both traditional and modern medicine simultaneously. Njoroge and Kibunga noted that herbal products were used as complementary therapy in the management of diarrhea by residents in Thika, Kenya [151]. The lack of enquiry about Traditional Complementary and Alternative Medicine (TCAM) use and the conventional healthcare providers’ negative attitude towards TCAM were cited as some of the reasons why patients fail to reveal their TCAM use [152].The regulatory framework for the practice of traditional medicine in Kenya is still underway [153], but several crude drugs or formulated herbal products with reported antibacterial activity are already available in the Kenyan market, for example, the Lifebuoy germ protection antibacterial herbal hand and body soap and the Dettol herbal bar soap. Skin care products (soaps and lotions) formulated from plant extracts (Thevetia peruviana, Tithonia diversifolia, Azadirachta indica, Aloe secundiflora) had antimicrobial properties. Soap made from Tithonia diversifolia plant extract was the most effective against E. coli, while Azadirachta indica soap was the most effective against C. albicans. T. diversifolia soap exhibited the highest activity against E. coli [154].The ethanolic extract ofE. divinorum root bark had a MIC of 25, 50, and 25 μg/ml for Streptococcus pyogenes, Staphylococcus aureus, and Escherichia coli, respectively (Table 1). A herbal toothpaste formulated with the ethanol extract of E. divinorum root bark had a higher antimicrobial activity against the tested microorganisms compared to Colgate herbal toothpaste formulated with fluoride [77]. Also, the formulation containing the aqueous extracts of T. asiatica (50 mg/ml) stem bark exhibited pronounced antimicrobial activity as indicated by zone of inhibition diameters of 24 mm (MRSA) and 22 mm (M. gypseum) compared to 22 mm and 14 mm, respectively, by the commercial hand wash (50 mg/ml). In the model hand washes efficacy experiment, the formulated herbal detergent attained a 78.8% reduction of pathogenic load as compared to 67.9% reduction with the commercial hand wash [37].Unfortunately, despite the surge in the consumption herbal products and the limited number of standardized herbal products in the Kenyan market, the pharmacovigilance for herbal medicines is nonexistent in Kenya [155]. The increased demand for herbal products has resulted in the market being flooded with adulterated products and false herbal claims on the products’ labels for marketing purposes. For instance, 50% of the investigated products by Ngari et al. [75] lacked antimicrobial activity against test bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus subtilis, Candida albicans, Escherichia coli, Streptococcus mutans, Enterococcus faecalis, and Lactobacillus acidophilus). The evaluation of herbal suspensions (used in the management of oral health in Nairobi County, Kenya) by Ngari et al. [75] reported a lack of detectable phytochemicals in the suspensions and noted that this occurrence could be due to very low concentrations of phytochemicals that could not be detected by standard laboratory methods or mineral adulterants might have been used. Studies have demonstrated that antimicrobial properties of natural products can be enhanced by the addition of metal ions [14, 156].


## 4.3. Polyherbalism

The use of herbs as combinations is common practice with many herbal practitioners and aimed at giving better results as compared to single herbs and also treating more than one ailment [157]. Ngari et al. [75] evaluated herbal pastes and suspensions used in the management of oral health in Nairobi County, Kenya, and various products showed significant antimicrobial activity that is comparable to positive control. For example, product HS4 composed of W. ugandensis, M. piperita, and S. aromaticum had ZOI of 33.1 ± 0.85 mm, 20.3 ± 1.71 mm, and 19.3 ± 1.65 mm against E. coli, S. aureus, and P. aeruginosa, respectively, compared to that of co-trimoxazole of 27.5 ± 0.7 mm, 8.5 ± 0.5 mm, and 10 ± 0.0 mm, respectively. Product HS5 composed of Aloe vera gel, W. ugandensis, and W. sominifera had a ZOI of 25.3 ± 0.25 mm, 20.25 ± 1.26 mm, and 21.5 ± 1.71 mm against E. coli, S. aureus, and P. aeruginosa, respectively, compared toco-trimoxazole 27.5 ± 0.7 mm, 8.5 ± 0.5 mm, and 10 ± 0.0 mm, respectively. This biological activity is attributed to the presence of various secondary metabolites in plants [14].Mbuthia et al. evaluated the synergistic properties of water-soluble green and black tea extracts with penicillin G. The antimicrobial results showed a marked increase in the inhibition zone diameters on the combination of green tea extracts with penicillin G. The catechins, theaflavins, and thearubigins are the antimicrobial agents present in tea [67].4 Synergistic inhibition by green tea extracts and penicillin G is due to the presence of dual binding sites on the bacterial surface for antibiotic and tea extract [158].


## 4.4. Bioactivity/Assay Methods

Disc diffusion method was the preferred method to assay for antibacterial activity. A clearing zone of 9 mm or greater for Gram-positive and Gram-negative bacteria was used as the criterion for designating significant antibacterial activity [159]. The in vitro MIC results were classified as described in the study by Pessini et al., 2003: the antimicrobial activity of the extracts that displayed MIC lower than 100 μg/ml was considered very high; 100–500 μg/ml, high; 500–1000 μg/ml, moderate; 1000–4000 μg/ml, low; and anything above this, inactive. The plants with the strongest antimicrobial activities were Toddalia asiatica, Hagenia abyssinica, Ocimum gratissimum, Harrisonia abyssinica, Conyza sumatrensis, Senna didymobotrya, Aloe secundiflora, Olea Africana, Vernonia glabra, Camellia sinensis, Tetradenia riparia, and Tarmarindus indica as they exhibited high mean inhibition zone values or low minimum inhibitory concentration (MIC) values.Several plants exhibited a high activity superior or comparable to the standard antibiotic drugs (Table1); the methanol-dichloromethane extract (100 mg/ml) of Harrisonia abyssinica had a ZOI of 20 ± 1.6 mm compared to gentamycin (ZOI of 18 ± 1.2 mm) against S. aureus and a ZOI of 30. ± 1.7 mm against E. coli compared to gentamycin ZOI of 15.1.3 mm against E. coli [41]. The methanolic extract of Croton macrostachyus exhibited ZOI (23.66 mm) compared to (21.33 mm) amoxicillin against S. aureus and ZOI (18.0 mm) compared to (17.58 mm) amoxicillin against P. aeruginosa. The methanolic extract had an MIC of 37.50 mg/ml compared to 18.75 mg/ml cefpodoxime against S. aureus and 18.75 mg/ml compared to 9.372 mg/ml cefpodoxime against P. aeruginosa [79].Plants such asToddalia asiatica, Hagenia abyssinica, Senna didymobotrya, Aloe secundiflora, and Camellia sinensis displayed good activities; thus, they may be considered for the assessment of in vivo activity and possibly formulated into different consumable forms. Korir et al. recommended that for plants with very low or no activity, bioactivity on all parts of the plants, for example, root, stem bark, and leaves combined ought to be done against a wide variety of pathogenic bacteria in order to conclusively report that a certain plant is inactive [29].


## 4.5. Toxicity

Despite herbal remedies being affordable, their lack of efficacy and safety evaluation is a great impediment to their acceptance into mainstream medicine. The safety assessment of herbal remedies remains a challenge as most of the studies of herbal medicines are directed at the toxicological properties of single plant formulations, yet most herbal preparations, especially those used in traditional medicine, contain multiple herbs [160].From this review, 45% of the plants were relatively safe, 44% of the plants have not been assessed for their safety, and 11% of the plants were reported to have high toxicity (Table1). The plants with very high toxicity can be further explored for the antitumor activity or as insecticides.


## 4.6. Plant Conservation Status

Other thanW. ugandensis and Prunus africana, most of the plants identified in this review are largely available and are not under any serious threat to become extinct. Since most of them are obtained from wild habitats, sustainable use of the reported medicinal plants against bacterial infections is advised as a conservation measure. The cultivation of wild medicinal plants is an important approach to safeguard the herbal industry. Biotechnological techniques such as plant cell or tissue culture, biochemical conversions, and clonal propagation of indigenous medicinal plants are another potential strategy in improving herbal medicine [161].


## 5. Conclusion

This review demonstrates the potential of medicinal plants to treat bacterial infections alongside justifying the use of these plant traditional medicine. It may serve as a starting point of research geared towards the clinical application of these plants. There is a need for standardization to improve the acceptance of herbalism by mainstream health practitioners.


## 6. Recommendation

Further research into thein vivo activity of plants displayed remarkable in vitro activity. Plants exhibiting strong antibacterial activity can be evaluated for their interactions with conventional antibiotics, and those displaying synergistic activity may provide useful leads in antibiotic therapy.



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*Source: 9089360-2022-03-24.xml*