Antimicrobial, In-vitro Free Radical Scavenging, Antioxidant Properties of Leaf, Bark and Root Extracts from Khaya senegalensis

Abstract

Khaya senegalensis is a very important medicinal plant in the tropics and has been utilized for treatment purposes which centered around protozoan as well as bacterial diseases. The phytochemical analysis, antioxidant, free radical scavenging activities and antimicrobial properties of K. senegalensis were investigated using various modern and modified techniques. The plant has been shown to contain secondary metabolites such as alkaloids, saponins, tannins, cardiac glycosides, steroids and flavonoids which are thought to give the plant its medicinal values. The bark and root extracts of K. senegalensis demonstrated hydroxyl (with EC50 values of 278.23, 401.34) and DPPH scavenging activities (with EC50 values of 95.76, 107.43) and lipid peroxidation inhibition properties with EC50 values of 132.12, 157.65 respectively which are by far higher than the EC50 ((50% effective concentration)) values of ascorbic acid of 223.55, 76.11 and 86.22 respectively. DPPH (2,2-diphenyl-1-picrylhydrazyl) is a radical and a trap ("scavenger") for other radicals. The zones of inhibition created around test organisms (both bacterial and fungal isolates) are reasonably comparable with standard antibiotics used as control. In most cases there was no significant difference (at p<0.05) between the standard and antibiotics and the extracts with zones of inhibition ranging from 12.2±0.02-22.5±0.01 for the extracts and 16.2±1.02-27.0±0.04 for standard antibiotics used in these experiments. The pharmaceutical world should take a very close and deep look at this tropical tree (Khaya senegalensis) once again with the aim of harnessing its enormous potentials as antimicrobial as well as antioxidant.