Antimicrobial Activities of the Constituents of Garcinia Kola Seeds

Abstract

Antimicrobial activity of seed extracts derived from Garcinia kola was studied in vitro. The seeds were successively extracted with petroleum ether, 70% ethanol and water. The ethyl acetate fraction of the ethanol extract, which showed the maximum antimicrobial activity, was recovered in a 2.4% w/w yield. Antimicrobial evaluation of the differential solvent extracts of G. kola seeds revealed that the petroleum ether, ethanol, the milky layer and ethyl acetate fractions possessed antimicrobial properties. The observed activity was due to the presence of a polyisoprenyl benzophenone (Kolanone) in the petroleum ether extract as well as the hydroxybiflavanonols present in the ethyl acetate fraction. GB1 (a hydroxybiflavanonol) was found to be the main component exhibiting significant (p<0.005) antimicrobial activity against Gram-positive and Gram-negative bacteria in a bacteriostatic manner and against Candida albicans and Aspergillus flavus in a fungistatic manner. The MIC of GB1 against S. aureus was 3.1 × 10⁻⁷ μg/ml and 3.0 × 10⁻³ μg/ml against E. coli.

Keywords::

• Antimicrobial
• Garcina kola