In vitro antimicrobial and radical scavenging activities of Adenanthera pavonina stem bark fractions
The present investigation deals with the in vitro antimicrobial and radical scavenging activities of four different fractions obtained from the stem bark of Adenanthera pavonina. Phytochemical screening of the fractions revealed the presence of alkaloids, flavonoids, glycosides, phenol, protein, saponins, steroids, tannins, and terpenoids. Evaluation of the extracts against three different bacterial strains (Escherichia coli, Salmonella typhimurium and Staphylococcus aureus) showed that the ethyl acetate fraction (F4) possess the best antimicrobial activity with good zones of inhibition. While antifungal activity against (Aspagillus flavus, Candida albican and Mucor) further indicate F4 has the best activity. Lastly, the radical scavenging activity revealed that the F1 (ethanol extract) and F4 (ethyl acetate fraction) demonstrated promising antiradical power on diphenylpicrylhydraxyl (DPPH) with an excellent percentage scavenging effect. At 1000 μg/mL and 10 μg/mL the DPPH activity of the ethyl acetate fraction was 97.9 and 71.3% respectively. While it was observed to be 94.9 and 69.6% for ethanol at 1000 and 10 μg/mL respectively. These values are found to be higher than that of the standard reference (ascorbic acid) which was 96.4 and 58.4 % at 1000 and 10 μg/mL respectively. This shows that the assay for DPPH free radical scavenging activity is concentration dependent. This strengthens part of the ethnomedicinal claims on the plant, Adenanthera Pavonina as a curative agent of different diseases of clinical concern.
Keywords: Adenanthera pavonina, Alkaloid, Antimicrobial, Ethyl acetate, Phytochemical, Radical