In vitro antibacterial activity of crude ethanol, acetone and aqueous Garcinia kola seed extracts on selected clinical isolates

Abstract

The study was conducted to screen for in vitro antibacterial activity of crude ethanol, acetone and aqueous seeds extract of Garcinia kola at different treatment regimes against some selected clinical bacterial isolates comprising of Gram positive and negative organisms namely; Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa and the major chemical groups responsible for the activity were determined. The agar well diffusion method was employed to determine the inhibitory effects of the seeds extract on the test microorganisms. The minimum inhibitory concentration exerted by the extracts against the bacterial isolates ranged between 3.125 and 25 mg/ml. The zones of inhibition exhibited by the extracts against the tested bacterial isolates ranged between 4.0 and 10.5 mm. The crude ethanol extract was found to exhibit more significant (P<0.01) inhibitory action against all the bacterial isolates at the various treatment regime. Also, compared to crude acetone and aqueous extracts, it was also notably found to exhibit significant (P<0.05) effects against the bacterial isolates. The preliminary phytochemical test revealed the presence of flavonoids, tannins, saponins, sterols and terpenes as the major chemical groups in the plant extracts. The results of this study revealed that the in vitro antibacterial activity exhibited by the seeds extract may be attributed to the presence of these phytochemical compounds.

Key words: In vitro antibacterial activity, phytochemical, Garcinia kola seeds, bacterial isolates.