Evaluation of the Antiplasmodial Activity and Lethality of the Leaf Extract of Cassia alata L. (Fabaceae).

Objective: Cassia alata L. (Fabaceae), one of the three plants contained in Saye, a polyherbal antimalarial remedy was assessed for its antimalarial potential and safety in mice.

Methodology: Organic extracts were prepared from the leaves and tested on the D 10 chloroquine-sensitive strain of Plasmodium falciparum using the parasite lactate dehydrogenase assay. The 4 days suppressive test using Plasmodium berghei in mice was used to evaluate the in vivo antiplasmodial activity of the extracts. Animals were treated by oral route, once a day with 50, 100, 250 and 400 mg kg -1 b.wt., of the extracts. The acute toxicity of the extracts was assessed in mice according to Thompson and Weil method. The lethal effects of the extracts on animal's body weight, tissues, biochemical and haematological parameters were determined at 823.5, 1235.5, 1853 and 2779.5 mg kg -1 b.wt., respectively.

Results: The dichloromethane/methane (1:1, v/v) extract of Cassia alata was the most active against Plasmodium falciparum. The mean percent suppression of parasitemia in mice was equal to 22.5, 41.8 and 45.2% at 50, 250 and 400 mg kg -1 b.wt., respectively. No death and no clinically significant changes were recorded in mice. The maximum non-lethal dose was more than 16875 mg kg -1 in animals. No significant changes were observed in body weight, tissues morphology, biochemical and hematological parameters at doses above or equal to 2779.5 mg kg -1 b.wt.

Conclusion: The dichloromethane/methanol leaf extract of Cassia alata had a good to moderate in vitro and in vivo antiplasmodial activity and was found to have low toxicity at high doses in tested animals.