African Journal of Virology Research

African Journal of Virology Research ISSN 2756-3413 Vol. 14 (2), pp. 001-005, February, 2020. © International Scholars Journals

Full Length Research Paper

Isolation of an antibacterial stilbene from Combretum woodii (Combretaceae) leaves

J N Eloff*, J O Famakin and D R P Katerere

Programme for Phytomedicine, Department of Paraclinical Sciences, Faculty of Veterinary Sciences, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa.

Accepted 28 September, 2019

Abstract

Acetone extracts of C. woodii leaf powder was separated by solvent-solvent partition into six fractions. The highest total activity was in the chloroform fraction. This fraction contained mainly one compound active against S. aureus. This compound was isolated by bioassay-guided fractionation using silica gel open column chromatography and identified by nuclear magnetic resonance (NMR) and mass spectroscopy (MS) as the stilbene 2’,3’,4-trihydroxyl-3,5,4’-trimethoxybibenzyl (combretastatin B5) previously isolated from the seeds of C. kraussii. It showed significant activity against S. aureus with an MIC of 16 µg/ml but with lower activity towards P. aeruginosa (125 µg/ml), E. faecalis (125 µg/ml) and slight activity against E. coli. This is the first report of the antimicrobial activity of combretastatin B5. Its concentration in the leaves was in the order of 5-10 mg/g which makes the use of non-polar leaf extracts a viable proposition in treating some infections, particularly in resource-poor settings.

Key words: Combretastatin B5, bibenzyl, stilbene, antibacterial, Combretaceae