Antimalarial Activity and cytotoxicity profile of the seed extracts of Garcinia kola (GUTTIFERAE)

Background: The emergence of parasite resistance to artemisinins typified by slower parasite clearance rates in some parts of South east Asia has necessitated the search for alternatives. Objective: This study evaluated the in vitro and in vivo antimalarial activity and the cytotoxicity profile of the n- hexane, dichloromethane and methanol extracts of Garcinia kola seeds. Methods: In vitro susceptibility of chloroquine-sensitive PF D10 strain to the extracts was evaluated using parasite lactate dehydrogenase assay while cytotoxicity was determined using 3-[4,5-Dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide (MTT) assay with Vero cells and emetine as standard drug. Chloroquine-resistant P. berghei (ANKA) infected Swiss mice allotted into 14 groups of 5 per group: corn oil (5mL/kg), 50, 100, 200, 400 mg/kg of each extract and chloroquine (10 mg/kg) were used to evaluate in vivo antimalarial activity in a 4-day suppressive test. Results: The n-hexane, dichloromethane and methanol extracts of the seeds of Garcinia kola were active in vitro against chloroquine sensitive P. falciparum D10 strain with IC50 values ≤ 26 µg/mL. The hexane and dichloromethane extracts were non- cytotoxic against Vero cells with IC50 values ≥ 27 µg/ml The hexane extract of Garcinia kola seeds reduced parasitemia by 70% at 400 mg/kg and prolonged survival in mice infected with P. berghei ANKA. Conclusion: The observed antimalarial activity justifies the use of Garcinia kola seeds in the treatment of febrile illnesses.