Abstract

The aim of the present study is to determine the in vitro antimicrobial activity of various extracts, partitions and fractions of Muntingia calabura (Elaeocarpaceae) leaves against a selected panel of microorganisms. The leaves of M. calabura were soaked separately in the aqueous, chloroform and methanol solvent systems in the ratio of 1:20 (w/v) for 72 h and these procedures were repeated three times. Antimicrobial testing was carried out using the micro-broth dilution method. The microbes targeted were Staphylococcus aureus 25923, S. aureus 33591 (a multi-drugs resistant S. aureus (MRSA) isolate), Escherichia coli 35218, Pseudomonasaeruginosa ATCC 27853, Candida albicans 10231 and Microsporum canis ATCC 36299. The methanol extract inhibited MSSA (MIC = 1250 µg/ml; MBC = 1250 µg/ml) and MRSA (MIC = 1250 µg/ml; MBC = 1250 µg /ml) and considered the most effective extract and was further partitioned sequentially using the aqueous, petroleum ether and ethyl acetate. The ethyl acetate partition exhibited effective antibacterial activities with the MIC/MBC value of 156 and 313 µg/ml against S. aureus 25923 and S. aureus 33591, respectively. The ethyl acetate partition underwent fractionation process and yielded 15 fractions (A1-A15) of which only fractions A9 to A15 effectively inhibited the growth of S. aureus 25923 and S. aureus33591 with MIC/MBC values ranging from 78 to 2500 µg/ml.

Key words: Muntingia calabura, Elaeocarpaceae, antimicrobial activity, micro-broth dilution, ethyl acetate fraction.