Abstract

The aim of the present study was to investigate the antimicrobial activity and to carryout phytochemical screening of aqueous and ethanol extracts of the leaves of Momordica charantia L. The result of the phytochemical screening revealed the presence of alkaloids, tannins, saponins, flavonoids and cardiac glycosides. However, the antimicrobial activity was investigated by agar-well diffusion method against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. The result showed that at a concentration of 100 mg/ml, both aqueous and ethanol extracts inhibited the growth of all the tested pathogenic bacteria, though with varying degrees of susceptibility of the bacterium. The diameter of zones of inhibition obtained ranged from 17 to 14 and 15 to 11 mm for ethanol and aqueous extracts, respectively. The minimum inhibitory concentration (MIC) values ranged from 6.5 to 12.5 mg/ml for the ethanol extract and 12.5 to 50 mg/ml for the aqueous extract. Similarly, the minimum bactericidal concentration (MBC) values ranged from12.5 to 25 mg/ml for the ethanol extract and 50 to 100 mg/ml for the aqueous extract. Also, the antimicrobial activity of both extracts was more under acidic conditions and at elevated temperatures. The results obtained in this study support the use of M. charantia in herbal medicine and it could be used as a source of broad spectrum oral antimicrobial agent for the treatment of diseases associated with these pathogenic bacteria investigated.

Key words: Momordica charantia L., antimicrobial, phytochemical screening, microorganisms, herbal medicine.