Phytochemical analysis and in-vitro antimicrobial screening of the leaf extract of Senna occidentalis (Fabaceae)

Abstract. Tamasi AA, Shoge MO, Adegboyega TT, Chukwuma EC. 2021. Phytochemical analysis and in-vitro antimicrobial screening of the leaf extract of Senna occidentalis (Fabaceae). Biofarmasi J Nat Prod Biochem 19: 57-64. Due to the use of Senna occidentalis as an antimalarial, anti-inflammatory, antioxidant, hepatoprotective, and antibacterial agent traditionally, this study examined the phytochemical composition and antimicrobial activity of the isolated methanol, ethyl acetate, and hexane fractions of the leaves of Senna occidentalis. Qualitative and quantitative phytochemical analyses were carried out using standard procedures. Antimicrobial activity was performed by using standard procedures against known common clinical isolates. Qualitative phytochemical analysis showed the abundant presence of saponins, tannins, flavonoids, and terpenoids in the ethyl acetate fraction. Cardiac glycosides were not detected in all the tested isolated fractions while steroids were found to be present and abundant in ethyl acetate and hexane fractions respectively. Quantitative phytochemical analysis showed that the methanol fraction contained 4%w/w alkaloids, 0.51%w/w flavonoids, 9.5%w/w saponins, 1.3%w/w tannins 5.5%w/w terpenoids, and 0.6%w/w total phenol content. The antimicrobial susceptibility test shows a range of inhibitory zone of 10-16 mm. Hexane fraction has the highest zone of inhibition against Candida albicans. The lowest MIC values of 0.6mg/mL and 0.2mg/mL were observed in ethyl acetate fraction against Candida albicans and Escherichia coli respectively. The highest MIC was 20mg/mL was observed in the ethyl acetate fraction against Staphylococcus aureus. The MMC values were varied widely. The MMC value against Bacillus subtilis, Candida albicans, and Trichophyton rubrum was 5mg/mL while the MMC value against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli was 20mg/mL. The results from this study show that the leaves of Senna occidentalis can serve as a potential source of some phytochemicals and also have the potential to be developed as a source of antibiotics.