Anti-Bacterial and Anti-Oxidant Activities of Leaf Extracts of Combretum vendee (Combretecacea) and the Isolation of an Anti-Bacterial Compound

Background: Combretum vendae A.E. van Wyk (Combretaceae) is used for the treatment of bacterial related infections and oxidative related diseases by indigenous people of South Africa. Dried leaves extracts of C. vendae were investigated for bioactivity against a variety of bacterial strains and their antioxidant potential evaluated.Materials and methods: Constituents of leaf material were serially extracted using solvents of varying polarities, TLC chromatograms of thefractions were sprayed with 2,2 diphenyl-1-picrylhydrazyl (DPPH) to determine the presence of antioxidant compounds. Bio-autography wasused to determine the number of antibacterial compounds active against Staphylococcus aureus, Enterococcus faecalis, Eschericha coli and Pseudomonas aeruginosa. Minimum inhibitory concentration (MIC) values were determined using serial microplate dilution method. The chloroform fraction was subjected to bio-assay guided column chromatography to isolate the active compound.Results: The mass extracted by different solvents was below 10% dry weight. MIC values for different extracts against different pathogensranges from 0.08 to 0.64 mg/ml. The compound isolated was identified as acacetin having an Rf value of 0.28 following elution in the Ethanol:Methanol: Water [E: M: W (10: 1.35: 1 v/v). Acacetin had MIC values ranging from 0.16 to 0.35 mg/ml.Conclusion: We report for the first time the isolation of acacetin as the main antibacterial compound from the leaves of Combretum vendae.Key words: Combretum vendae, Minimum Inhibitory Concentration, Bio-autography, acacetin, Phytochemical analysis, Anti-oxidan