Isolation and characterization of propitious bioactive compounds from Cassia singueana L.

Cassia singueana L. is widely used in traditional medicine for the treatment of various ailments. The present work was set to investigate the antioxidant and antimicrobial activity of this plant and its secondary metabolites. Three bioactive compounds, lupeol, eugenol and octadecadienoic acid methyl ester, were isolated from the root extract of the plant using bioactivity-guided normal phase column chromatography. The antioxidant effect was studied using the in vitro assays, e.g., 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), superoxide anion and metal chelation methods. The compounds were screened for their antimicrobial activity against four bacteria, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumonia and a fungus, Candida albicans using the agar diffusion method. The MIC/MBC of the extracts were determined by the micro-dilution method. Chemical structures of the isolated compounds were determined using FTIR and NMR spectroscopy. Whilst all three compounds showed certain levels of antioxidant activity, the most prominent antimicrobial activity was observed only against S.aureus. In general, results from the work provided some evidence to support the traditional medicinal uses of C. singueana