<i>In vitro</i> antiplasmodial activity of aqueous extracts of <i>Ochna schweinfurthiana</i> leaf on <i>Plasmodium falciparum</i>

Abstract

The in vitro antiplasmodial activities of cold and hot aqueous extracts of Ochna schweinfurthiana leaf was evaluated against Plasmodium falciparum at concentrations 10, 20, 40 and 80 μg/ml. Parasitaemia was observed after 24, 48 and 72 hours under a light microscope at X100 magnification. The antiplasmodial activity of the extracts were compared with a standard Artemisinin-based Combination Therapy (ACT), artemether/lumefantrine. Phytochemical analysis showed the presence of flavonoids (65.97 mg/100g), alkaloids (0.20 mg/100g), saponins (47.39 mg/100g) and tannins (0.53 mg/100g). There was a significant reduction (P< 0.05) in parasitemia of groups treated with the various doses of the extracts when compared to the control group. The reduction in parasitemia was however not as pronounced as that observed for the standard drug-treated groups. The 10, 20, 40 1nd 80 μg/ml doses of the extracts gave a percentage parasite inhibition of 79.77, 81.86, 83.38 and 86.42 (cold extract) and 76.26, 78.54, 82.72 and 85.06 (hot extract) respectively which are lower than 99.71, 99.81, 100.00 and 100.00 respectively observed for the standard drug after 72 hours. However, in vitro assay of plasmodium lactate dehydrogenase (pLDH) activity did not show any significant difference among the extract-treated groups and those treated with artemether/lumefantrine standard. Findings from this study show that hot and cold aqueous extracts of Ochna schweinfurthiana leaf possess high inhibitory activity against Plasmodium falciparum in vitro especially after 72 hours and justifies it folkloric use as an antimalarial.

Keywords: Antiplasmodial; Ochna schweinfurthiana; Extracts; Parasitemia; ACT