In Vitro Antimicrobial activity of “Antibact” and its component plants against clinical bacterial isolates.

Plants used for traditional medicine contain a wide range of substances which can be used to treat various infectious diseases. Hence, ethanol and water extracts from the following plants were analyzed: Psidiumguajava(guava), Cymbopogoncitratus (lemongrass), Hoslundiaopposita, Phyllanthusfraternusand a formulation, “Antibact” comprising of a combination of the above mentioned plants. These plants were selected based on existing traditional medicine knowledge, usage and their potential as antimicrobial agents. The antimicrobial activity of the plant extracts were evaluated against twenty one antibiotic susceptible and resistant bacterial strains using agar-well diffusion method. In addition, the possible in vivo toxic effect of “Antibact” was studied. Phytochemical screening showed that the herbal medicinal extracts under study contained saponins, reducing sugars, phenolics, polyuronides, triterpenes, alkaloids flavonoids, and phytosterols. The antibacterial activity was more in ethanol extracts compared to aqueous extract in all the plants indicating that the active compounds responsible for antibacterial activity is more soluble in organic solvents. The highest antimicrobial potentials were observed for the extracts of P. guajavainhibiting 57% and 71.4% of the microorganisms used for aqueous and ethanolic extracts respectively, 57% and 48% for P. fraternusfollowed by H. oppositainhibiting 24% and 14.3% while C. citratus extracts did not present any antimicrobial activity. Preparations made from the plant extracts were active against some of thecontrol strains of bacteria used in this study; P. mirabilis ATCC 49565, P. aeruginosaATCC 27853, S. aureusATCC 25922, S. saprophyticusATCC 15305, S. typhi ATCC 19430 and S. typhimuriumATCC 14028. The most resistant species were E. coli, K. pneumoniae, S. typhi, and S. typhimuriumbeing resistant to all the plant extracts used in this study. The ethanol extract of “Antibact” was more effective than the aqueous extract inhibiting the growth of thirteen out of twenty one (62%) microbes used while the aqueous “Antibact” inhibited the growth of a total of five out of twenty one (23.8%) microorganisms used with an average zone of 2.32 ± 0.93mm and 6.68 ± 1.26mm respectively. Gram-negative bacteria were less sensitive than Gram-positive bacteria, which may be due to their differences in the cell wall composition. The low MICs observed ranging from 0.5 to 32.0mg/ml during the study indicate that these herbal preparations are efficacious and can be used for the management of diseases caused by the test organisms. Results obtained support the use of these plants in traditional medicine and suggest that some of the plant extracts possess compounds with good antibacterial properties that can be used as antimicrobial agents in the search for new medicines. Further study should involve investigating the potential of additional medicinal plant(s) which are known to inhibit the growth of Gram negative bacteria in order to make “Antibact” more effective, investigation of the phytochemical present in “Antibact” responsible for the antibacterial effect in this study and testing of efficacy of “Antibact” using laboratory animals such as mice, guinea pigs and rabbits.

Source: KNUST