In vitro antiplasmodial screening of ethnopharmacologically selected South African plant species used for the treatment of malaria

Abstract

ETHNOPHARMACOLOGICAL RELEVANCE : The investigated plant species are traditionally used by Venda people of South Africa, in the treatment of malaria and associated symptoms. AIM OF STUDY : To evaluate the in vitro antiplasmodial efficacy and cytotoxic properties of indigenous medicinal plants used by Venda people against malaria. MATERIALS AND METHODS : In vitro antiplasmodial activity and cytotoxic properties were evaluated on twenty indigenous plant species. Ground plant material was extracted in dichloromethane: 50% methanol (1:1). Antiplasmodial activity was evaluated against the chloroquine-sensitive strain of Plasmodium falciparum (NF54). The cytotoxicity of the plant extracts were assessed against mammalian L-6 rat skeletal myoblast cells. The selectivity index (SI) values were then calculated. RESULTS : Of the 43 plant extracts evaluated, 10 exhibited pronounced antiplasmodial activity (IC50 ≤ 5μg/ml) with good therapeutic indices (SI ≥ 10). Lipophilic plant extracts were relatively more potent than polar extracts. Tabernaemontana elegans Stapf. (Apocynaceae) and Vangueria infausta Burch. subsp. infausta (Rubiaceae) extracts displayed significant antiplasmodial activity (IC50 < 2 μg/ml). CONCLUSION : Findings of this study partly support the ethnomedical use of the investigated plant species by Venda people as antimalarial remedies. The study also highlights some of the knowledge gaps that require further phytochemical studies on the specified plant species.