Evaluation of Antibacterial Activities of Fractions from Ethanol-Extracted Residues of Piper guineense Leaves on Gram Negative Clinical Isolate

The problem of drug resistance to orthodox antimicrobial agents has remained a setback in the treatment of bacterial infections in the modern society. Adverse effects, coupled with scarcity and high cost of orthodox drugs have necessitated interest in the search, development and use of antibacterial agents from plant origin. Piper guineense is claimed in traditional medicine as a remedy for gram negative organism-transmitted infections. The leaves of Piper guineense plant was collected, washed, dried at room temperature and pulverized. The plant material was extracted with 80% ethanol. The ethanol-extracted residue was subjected to fractionation. Seventeen fractions were obtained, and were pooled together based on their Rf values into five pooled-fractions labeled: PF-1, PF-2, PF-3, PF-4, PF-5. Both the ethanol and fraction extracts were subjected to phytochemical analysis, preliminary antibacterial screening, minimum inhibitory and minimum bactericidal concentrations determination using both clinical isolates and type culture organisms. The yield of ethanol-extracted residue was low (21.08g) when compared to the amount of pulverized plant material (500g). Phytochemical analysis revealed the presence of flavonoids, alkaloids and terpenoids in all the extracts. The extracts produced statistically significant lower zone of inhibition (p<0.05) when compared with the standard drug (amoxicillin), it also demonstrated activity against test organisms used in the study. The findings of this study demonstrated that ethanol leaf extract of Piper guineense possess antibacterial activities, therefore justifies the traditional claim of the plant.