Abstract

The antimicrobial activity of the methanolic root extract and compounds isolated from Croton membranaceus against the bacteria; Staphylococcus aureus,Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and fungi; Aspergillus niger and Candida albicans, using the agar diffusion and broth dilution techniques was studied in order to establish its possible usefulness in the treatment of measles. The methanolic extract showed a significant (p < 0.01) antibacterial and antifungal activity against the test organisms used with minimum inhibitory concentrations (MICs) ranging from 0.53 - 1.43 mg/ml. Out of the six compounds tested (crotomembranafuran, gomojoside H, julocrotine, β-sitosterol, β-sitosterol-3-D-glucoside, and DL-threitol), gomojoside H, showed significant antibacterial activity against; S. aureus, B. subtilis and P. aeruginosa (MICs < 10 μg/ml). The other compounds exhibited no significant antimicrobial activity (MICs > 200 μg/ml). The activities of gomojoside H were found to be similar to the effects of gentamicin on these organisms. The results therefore indicated that this compound is a potent antibacterial and its presence appears to explain in part the antimicrobial activity exhibited by the C. membranaceus root extract and supports its usefulness in treating secondary bacterial infection in measles.

Key words: Croton membranaceus, gomojoside H, antibacterial activity, measles.