Abstract

Crude n-hexane extracts of the seed of Garcinia kola were screened for their in-vitro anti-Vibrio activities against 50 Vibrio bacteria isolated from wastewater final effluents in the Eastern Cape Province of South Africa. The extract at a screening concentration of 10 mg/ml resulted in zones of inhibition ranging from 10 to 14 mm against the susceptible isolates and the minimum inhibitory concentrations (MIC) varied between 0.313 and 0.625 mg/ml. The rate of kill assay was done against 3 representative isolates namely Vibrio vulnificus (AL042), Vibrio parahaemolyticus (AL049) and Vibrio fluvialis (AL040). The results showed appreciable biocidal activity after 2 h exposure time at 4 × MIC with V. vulnificus(AL042) having 91.6% bacteria cells killed; V. parahaemolyticus (AL049) had 92.6% cells killed and V. fluvialis (AL040) had 96.3% killed. We conclude that G. kola seeds are a potential source of compounds that could be useful in the treatment of infections caused by Vibrio bacteria.

Key words: n-hexane extract, Garcinia kola, Vibrio species, minimum inhibitory concentrations, rate of kill.