ASSESSMENT OF ANTIBACTERIAL ACTIVITIES AND PHYTOCHEMICAL SCREENING OF FLAMBOYANT TREE LEAF EXTRACTS AGAINST SELECTED BACTERIA

Abstract

Delonix regia plant is one of the useful plants that have antimicrobial activities against pathogenic microorganisms. The different parts of this plant, the stem, back, pod, seed, flower and to a lesser extent leaf have been investigated for antimicrobial activities. The aim of this study is to determine the antibacterial activity and phytochemical constituents of the leaf of D. regia. The powdered leaf of D. regia was subjected to extraction with ethanol and petroleum ether using soxhlet extractor and the extracts were concentrated in rotary evaporator. The crude extracts of both ethanol and petroleum ether were assayed for antibacterial activity against Escherichia coli, Bacillus subtilis, Micrococcus luteus and Pseudomonas aeruginosa by agar well diffusion method. The MIC and MBC of the crude extracts to test organisms were determined by broth micro dilution method. The quantitative (percentage yield) as well as the phytochemical constituents of the extracts were determined. The maximum zones of inhibition observed from ethanol extract against Escherichia coli (26.33mm) and petroleum ether extract against Bacillus subtilis (21.66m). The extracts were found to contain eight phytochemicals namely: anthraquinones, tannin, cardenolides, phlobatannin, terpenes, phenol, steroid, and alkaloids. Alkaloids was the predominant phytochemical while terpene was the least from both the ethanol and petroleum ether extracts. The yield of the extract from ethanol was higher (15.47%) than that from the petroleum ether (14.40%). The leaf extracts were found to be effective against all the test organisms used in this study. Key words: Delonix regia, Petroleum Ether, Bacterial Suspension, Phytochemical