Abstract

The antimicrobial activities of three plants (Momordica charantia, Morinda lucida, andHunteria umbellata) were investigated. These plants were extracted using methanol and ethanol as solvents. These extracts were used to evaluate the growth of five food borne bacteria namely; Bacillus sp, Proteus vulgaris, Streptococcus sp., Shigella sp.,Lactobacillus sp., and the research revealed zones of inhibition ranging from 0 to 36 mm. The minimal inhibitory concentration (MIC) of the extracts ranged from 20 to 100 mg/ml; that of the ethanolic extract of Momordica charantia against Bacillus sp. being the lowest (20 mg/ml) and most effective and that of M. lucida being the highest (100 mg/ml) and least effective. Most of the extracts were merely inhibitory against the organisms except ethanolic extracts of H. umbellata and M. charantia against Bacillussp., Streptococcus sp. and Lactobacillus sp. with the ethanolic extract of H. umbellatashowing the lowest MBC of 40 mg/ml. The activity indices of the extracts were calculated and the highest activity index (2.818) was that of the ethanolic extract of M. charantiaagainst co-trimazole using Bacillus sp. as the test organism. H. umbellata and M. charantia showed more promising potential as antimicrobial agents than M. lucidaagainst foodborne pathogens and hence against enteric diseases. These effective plants should be purified and further assayed for toxicological activity and possible use as drugs or preservatives.

Key words: Antimicrobial activity, foodborne pathogens, Momordica charantia, Hunteria umbellata, Morinda lucida, commercial antibiotics, activity index.