Antimicrobial effects of aqueous and ethanolic fractions of two spices, Ocimum gratissimum and Xylopia aethiopica

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.