Assessment of the antimicrobial activity of aqueous and ethanolic extracts of Piper guineense leaves

The antimicrobial activity of aqueous and ethanolic extracts of leaves of Piper guineense was determined on some bacteria and fungi, namely, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans and Saccharomyces cerevisiae, using agar well diffusion method and minimum inhibitory concentration (MIC). The ethanolic extract was found to show more activity than the aqueous extract on all the isolates. The diameter of zones of inhibition for the ethanolic extract ranged between 2 and 12 mm, while that of aqueous extract ranged between 5 and 8 mm. The MIC of the ethanolic extract was from 2.5 to 10 mg/ml, while for aqueous extract, the MIC was 10 to 20 mg/ml. Escherichia coli was found to show the greatest sensitivity, while P. aeruginosa showed the least sensitivity of all the isolates. The phytochemical analysis carried out on P. guineense leaves revealed the presence of alkaloids, tannins, saponins, glycosides and flavonoids. The presence of these phytochemicals supports the use of this plant as antimicrobial agent. P. guineense can therefore be used as antimicrobial agent. Key words: Piper guineense, antimicrobial, extracts, aqueous, ethanol, phytochemical.