## 6 Pharmacological Properties of _Apium_ Plants  
### Antimicrobial Activities of Apium Plants  
Antibiotics have been critical in the control of microbial infections. The emerging antimicrobial resistance throughout the world [149] emphasizes the research of new treatments. Natural resources, especially plants, are potent candidates for antimicrobial uses. Medicinal plants have a critical role in fulfilling the basic health needs and introduce a new source of natural antibacterial and antifungal agents [150]. Many naturally found compounds, such as essential oils extracted from edible and medicinal plants, herbs, and spices have been shown to possess antimicrobial functionality and serve as a natural antimicrobial agent against a wide range of food spoilage and pathogen microorganisms [130], thus, they have long been traditionally used for centuries due to their antifungal and antibacterial properties. Therefore, essential oil of _Apium_ plants can be assumed to be one of the important groups of natural sources for the development of broad-spectrum, safer and cheaper antifungal agents [151]. The main active compounds of these oils are primarily limone, pinene, and selienne [119; 130]. More particularly, phenolic constituents also have been reported to be responsible for these properties [152]. Antimicrobial properties of _Apium_ plants have been confirmed in several in vitro studies [153; 109; 151; 152]. Various epidemiological studies showed that _Apium_ plants play a significant role in the prevention of microbial growth with its antibacterial and antifungal effects [119]. [PERSON] et al. indicated that essential oil and aqueous extract from _A. gravelens_ showed antibacterial activity with MIC values of 0.01-0.25 mg/mL [109]. In a study by [PERSON] et al., the antimicrobial activity of the essential oil of this plant was determined in vitro against _Helicobacter pylori_ and, consequently, a MIC value of 12.5 mg/mL was obtained [34]. A study by [PERSON] et al. also revealed the inhibitory activity of _A. nodiforum_ essential oil against _Helicobacter pylori_[143]. [PERSON] et al. evaluated the antifungal activity of _A. nodiforum_ essential oil and extracts against yeasts, dermatophytes, and _Aspergillus_ spp [151]. According to their results, the MIC of the oil showed a variability of inhibition among all the fungi tested. Essential oil of _A. nodiforum_ from different origins showed significant activity against dermatophytes with MIC values ranging from 0.04 to 0.32 ug/mL. The oil for _Aspergillus fumigatus_ and _A. flavus_ is less effective against _Aspergillus_ spp., especially MICs of 2.5 and 5 ug/mL [151]. [PERSON] et al. also indicated that the occurrence of myristicin and dilapiol in essential oil could show a synergistic effect, which may explain the relatively higher antifungal activity against the same strains. These results support the potential application of _A. nodiforum_ essential oil in the treatment of dermatophytosis and candidosis [151]. Moderate antimicrobial activity was shown by _A. gravelens_ (leaves) against _Salmonella typhi_ that are resistant to most antibiotics [153]. _A. gravelens_ essential oil showed an inhibitory activity against _S. aureus_ and different _Listeria_ strains, whereas, _E. coli_ and several _Salmonella_ species remained unaffected. The inhibitory activity was also recorded against several fungal strains with varying efficiency. However, [PERSON] et al. indicated that extracts of _A. gravelens_ were very effective and showed good activity against _E. coli_, _S. aureus_, _S. typhi_, _B. subtilis_, and _P. aeruginosa_[154]. [PERSON] et al. showed that the essential oil of _A. gravelens_ was strongly inhibitory against _E. coli_ and moderately inhibitory against _P. aeruginosa_ and _S. aureus_[109]. [PERSON] and colleagues performed an experiment to evaluate the antimicrobial activity of _A. gravelens_ against several bacterial strains and fungal strains. They reported that all fractions of _A. gravelens_ showed good activity against _E. coli_, _S. aureus_, _S. typhi_, _B.