Antimicrobial activity of the aqueous and methanolic extracts of <i>Sesamum radiatum</i> (Schum and Thonn.)

Abstract

Sesamum radiatum (Schum and Thonn.) is a leafy vegetable belonging to the family Pedialiaceae, it is used traditionally in the treatment of conditions such as diarrhoea, dysentery and fungal infections.This study investigated the phytochemical constituents and the antimicrobial activity of Sesamum radiatum (Schum and Thonn.). The pulverized plant material was subjected to cold marceration using distilled water and methanol for the aqueous and methanolic extracts, respectively. The plant extracts were further subjected to phytochemical screening using standard procedures and in vitro antibacterial sensitivity tests using the disc diffusion method. Zones of inhibition, minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined. Flavonoids, terpenoids, cardiac glycosides and cardenolides were found in both the aqueous and methanolic extracts. The results of the in vitro antimicrobial susceptibility test showed that the aqueous extract inhibited the growth of Candida albicans at the highest concentration of 600 mg/ml with a zone of inhibition of 8.00±0.00 mm while the remaining microorganisms were resistant at all the concentrations. The methanolic extract inhibited the growth of Salmonella typhi at concentrations of 200 mg/ml, 400 mg/ml and 600 mg/ml and Pseudomonas aeruginosa at concentrations of 400 mg/ml and 600 mg/ml. In conclusion, the aqueous extract of Sesamum radiatum showed antifungal activities which may justify its folkloric use and the methanolic extract inhibited the growth of S. typhi which also justifies its use traditionally, in the treatment of dysentery and diarrhea.

Keywords: Antimicrobial, Phytochemical constituents, Sesamum radiatum, MIC, MBC