Antimicrobial effects of aqueous and ethanolic fractions of two spices, <I>Ocimum gratissimum</I> and <I>Xylopia aethiopica</I>

Abstract

Aqueous and ethanolic extracts of Ocimum gratissimum and xylopia aethiopica were analyzed for their antimicrobial activities against five pathogenic organisms; Staphylococcus aureus, Escherichia coli, Streptococcus fecalis, Pseudomonas aeruginosa and Lactobacilli. Ethanolic extracts of O. gratissimum had a minimum inhibitory concentration (MIC) of 30 mg/ml against S. aureus, E. coli, P. aeruginosa and lactobacilli while for S. fecalis the MIC was 15 mg/ml. Aqueous extracts of O. gratissimum had an MIC of 12.5 mg/ml against S. aureus, E. coli and S. fecalis, while for P. aeruginosa and lactobacilli the MIC was 6.25 and 25 mg/ml, respectively. Ethanolic extracts of X. aethiopica showed an MIC of 10 mg/ml in the five organisms tested. While its aqueous extract gave an MIC of 30 mg/ml for S. aureus and Lactobacilli, and 15 mg/ml for E. coli, P. aeruginosa and S. fecalis. Our findings suggest that the anti-microbial activity of these spices reside in their aqueous fractions and also indicate that very low concentrations are required to achieve antimicrobial effects.