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Submitted: 08 October 2012 Modified: 08 October 2012
HERDIN Record #: R04A-DLSHSI-12100813543757

Antimicrobial isothiocyanates from the seeds of Moringa oleifera lam.

Basic Research Unit/Research Division - De La Salle Health Sciences Institute

Abstract

4-(?-L-rhamnosyloxy)benzyl isothiocyanate (1) and 4-(4?-O-acetyl-?-L-rhamnosyloxy) benzyl isothiocyanate (2) isolated from Moringa oleifera seeds were screened for their antibacterial activities against Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, and Pseudomonas aeruginosa, and for their antifungal activities against Candida albicans, Trichophyton rubrum, and Epidermophyton floccosum using the disk diffusion method. Isothiocyanates 1 and 2 were found active at the lowest inhibitory concentration of 1 mg/ml against all the Gram-positive bacteria tested (S. aureus, S. epidermidis, B. subtilis) and against dermatophytic fungi, E. floccosum and T. rubrum. Statistically significant differences were found between the mean inhibition zones (IZ) of 1 and 2 and the standard drugs, ofloxacin and clotrimazole. The Minimum Inhibitory Concentration (MIC) values confirmed the good antimicrobial activity of 1 and 2 against S. aureus, good to moderate activity against S. epidermidis, moderate activity against B. subtilis, and weak activity against E. floccosum and T. rubrum. The in-vitro bactericidal effect of 1 and 2 against the Gram-positive bacterial strains tested was evidently suggested by MBC:MIC ratios of 2:1.