Analysis Of Antibacterial Activity Of Terminalia Sericea And Combretum Imberbe Two Combretaceae Species From Namibia

ABSTRACT

The study was conducted to investigate the antibacterial activities of stem and leaves from Terminalia sericea and the live and dead bark from Combretum imberbe. The aqueous and organic crude extracts of the two plants were tested on Gram-negative bacteria Escherichia coli, Shigella sonnei, Serratia marcescens, Helicobacter pylori and Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus and Clostridium perfringens using the disk diffusion method. All the crude extracts exhibited activity against the tested bacteria species except for extracts from C. imberbe (dead bark). Organic extracts had high activity with minimum inhibitory concentration (MIC) values of 0.1mg/ml for all plant parts against S. aureus , S. marcescens, and H. pylori whilst the aqueous extracts from T. sericea (stem and leaves) and C. imberbe (live bark) had MIC values of 1mg/ml all against S. marcescens and H. pylori. Fractions from the two plants were obtained by vacuum liquid chromatography (VLC) using different solvents with increasing polarity. The organic extract fractions from both plants were observed to have good activity against two of the seven bacterial species that were tested. The dead bark plant extracts from C. imberbe had MIC value of 10mg/ml with 100% Ethyl acetate extracts against the bacteria H. pylori. T. sericea leaf extracts had MIC value of 0.01mg/ml against H. pylori in 100% MeOH fractions whilst the stem extracts had activity at 0.01mg/ml against E. faecalis in 100% Acetone fractions. The results indicate that the two plants have good antibacterial activity hence further research is needed to isolate and identify active compounds which can be developed into effective drugs.