Preliminary study on the synergistic interaction of Garcinia kola and Vernonia amygdalina against Candida albicans

Introduction: Due to the emergence and spread of infections caused by Candida albicans especially among immunocompromised patients and increase in resistance by this group of fungi to commonly used antifungal agents, this study was undertaken to investigate the possible synergy between Garcinia kola seed and Vernonia amygdalina leaves extracts against organism. Methods: Ethanol extraction of Vernonia amygdalina leaves and Garcinia kola seeds were carried out and extract evaluated for anti-candida activities. The combined anti-candida activities of the extracts were also assessed using Checkerboard assay. Results: Extract of G. kola seed showed minimal anti-candida activity against the C. albicans with an inhibition zone of 5 mm and minimum inhibitory concentration of 50 mg/mL. The combined effect of both extract was demonstrated to be synergistic at most combination ratios tested. Furthermore, the combined effect was observed to have outweighed their individual effect, inhibiting the test isolates at concentration far less than the MICs of each of the extracts. The fractional inhibitory concentration index of the combined extracts at their various combination ratios against C. albicans ranged between 0.14 – 0.45 mg/ml indicating a synergistic effect by the various combinations against the organism. Conclusion: The combined activities by the two extracts showed marked improvement in anti-candida activities compared with their individual activities. The results support harnessing the individual bioactive constituents of the extracts and combining them for the development of potential antifungal agents.