Isolation, characterisation and antimicrobial activity of a steroidal ester from the leaves of Cassia nigricans vahl

The aim of the study was to scientifically validate the claims that C. nigricans is used in traditional medicine for the treatment of skin diseases, infections and wounds. The leaves of Cassia nigricans is said to be used in traditional medicine for the treatment of peptic ulcer, gastro-intestinal disorders, diarrhoea and skin diseases. The glycoside present in the methanol extract of the leaves was hydrolysed using dilute hydrochloric acid. A silica gel column of the resulting aglycone (using petroleum ether:ethyl acetate mixtures) gave a white amorphous powder, identified as steroidal ester by means of spectral analysis. The antimicrobial activity of the steroidal ester was investigated against Staphylococcus aureus, Streptococcus pyogenes, Corynebacterium pyogenes, Bacillus subtilis, Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Neisseria gonorrhoeae and Klebsiella pneumoniae using agar diffusion technique. The results showed that the compound was effective against all the test organisms and the minimum inhibitory concentration was found to be 2×103 μg mL-1. © 2009 Academic Journals Inc.