THE ANTIPLASMODIAL ACTIVITY AND TOXICITY PROFILE OF TEN SOUTH AFRICAN COMMIPHORA SPECIES

Abstract

The emergence of drug-resistant strains of Plasmodium falciparum has resulted in an urgent need to develop new antimalarial chemotherapeutic agents. Traditionally, Commiphora (Burseraceae) species, commonly known as ‘corkwood or kanniedood’, have been used in the treatment of fever, infections and malaria. In this first report on the antiplasmodial activity of South African Commiphora species, ten species were investigated along with their toxicity profiles. Aerial parts were collected from natural populations in the Limpopo Province (South Africa) and the leaves and stems extracted with chloroform:methanol (1:1). Antimalarial activity was determined against chloroquine-resistant Plasmodium falciparum using the tritiated hypoxanthine incorporation assay. The haemolytic properties of the extracts were assessed to differentiate between the direct antimalarial activity and the lytic nature of the extracts which would indirectly inhibit the growth of the intra-erythrocytic parasite. Of the twenty extracts, C. viminea (stem) and C. marlothii (leaves and stems) were more potent than C. glandulosa (leaves), C. tenuipetiolata (stems) and C. edulis (leaves). At 500µg/ml, C. mollis (stem) and C. neglecta (leaves) were haemolytic; however there was a favourable safety index with C. viminea (stem) and C. marlothii (leaves and stems). There was no linear relationship between the haemolytic nature of the extracts and their antimalarial activity, indicating that haemolysis does not contribute to the efficacy of the more active extracts. These findings validate the traditional use of South African Commiphora species as potential antimalarials.