Anti-bacterial and anti-oxidant activities of leaf extracts of Combretum vendae (Combretecacea) and the isolation of an anti-bacterial compound.

Npm Komape,Jn Eloff,Vp Bagla,Peter Masoko,Mutalib Aderogba,Jacobus Nicolaas Eloff,Nancy Patience Motlalepula Komape,Victor Patrick Bagla

doi:10.4314/ajtcam.v11i5.12

Abstract

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. Constituents of leaf material were serially extracted using solvents of varying polarities, TLC chromatograms of the fractions were sprayed with 2,2 diphenyl-1-picrylhydrazyl (DPPH) to determine the presence of antioxidant compounds. Bio-autography was used 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. The mass extracted by different solvents was below 10% dry weight. MIC values for different extracts against different pathogens ranges 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. We report for the first time the isolation of acacetin as the main antibacterial compound from the leaves of Combretum vendae.

Highlights

The World Health Organization’s (WHO) estimate indicate that 80% of more than 400 million inhabitants of the world rely on traditional medicines for their primary health care needs (WHO, 2008)
25 to 50 % of currently used pharmaceuticals are derived from plants but only few are in use as conventional antimicrobials (Bansal et al, 2012)
Similar compounds contained in the chloroform extract, that showed antibacterial activity on bio-autography, exhibited antioxidant activity

Summary

Introduction

The World Health Organization’s (WHO) estimate indicate that 80% of more than 400 million inhabitants of the world rely on traditional medicines for their primary health care needs (WHO, 2008). Western medicine is increasingly being receptive to the use of antimicrobials and other drugs derived from plants, as main stream antibiotics are becoming ineffective due to the emergence of resistant strains. The developments of resistant strains have made diseases intractable to conventional antimicrobials (Bansal et al, 2012). Another concern for the renewed interest in plant antimicrobials in recent years has been the rapid extinction of plant species (Lewis and Elvin-Lewis, 1995). These concerns have provoked renewed interest in the study of medicinal plants in term of conservation and as to whether their traditional uses are supported by actual pharmacological effects. Conclusion: We report for the first time the isolation of acacetin as the main antibacterial compound from the leaves of Combretum vendae

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Results