Potential of a Khaya ivorensis –Alstonia boonei extract combination as antimalarial prophylactic remedy

• Published in: Journal of ethnopharmacology 2011-09, Vol.137 (1), p.743-751
• Main Authors: Tepongning, Roselyne Nzangue, Lucantoni, Leonardo, Nasuti, Cinzia Carla, Dori, Geme Urge, Yerbanga, Serge Rakiswende, Lupidi, Giulio, Marini, Carlotta, Rossi, Giacomo, Esposito, Fulvio, Habluetzel, Annette
• Format: Article
• Language: English
• Subjects: Alstonia; Alstonia - chemistry; Alstonia boonei; Animals; Anopheles stephensi; Antimalarials - chemistry; Antimalarials - isolation & purification; Antimalarials - pharmacology; Antimalarials - toxicity; Apocynaceae; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Combinations; Female; Khaya; Khaya ivorensis; Lethal Dose 50; Malaria; Malaria - drug therapy; Malaria - parasitology; Male; Medicine, Traditional; Meliaceae; Meliaceae - chemistry; Mice; Mice, Inbred BALB C; Parasite Egg Count; Plant Bark; Plant Extracts - chemistry; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Plant Extracts - toxicity; Plants, Medicinal; Plasmodium berghei; Plasmodium berghei - drug effects; Plasmodium berghei - pathogenicity; Remedy validation; Toxicity; Toxicity Tests
• ISSN: 0378-8741; 1872-7573
• DOI: 10.1016/j.jep.2011.06.036

The antiplasmodial activity and the wide dose interval between the therapeutic dosage and the toxic dosage exhibited by the KA herbal combination in the murine malaria model argue in favor of its use as an antimalarial prophylactic remedy. The decoction of the combined stem barks of Khaya ivorensis A. Chev. (Meliaceae) and Alstonia boonei De Wild (Apocynaceae) has a history of use in traditional medicine of central Cameroon for malaria treatment but also for the prevention of the disease. The purpose of this investigation was to determine the antiplasmodial activity of Khaya ivorensis (K) and Alstonia boonei (A) preparations in the murine malaria model Plasmodium berghei/Anopheles stephensi, to estimate their prophylactic potential and to assess acute and sub-acute toxicity of the formulations prepared according to the traditional recipes. Aqueous extracts from the stem-bark of the two plants were prepared and tested separately and in combination. BALB/c mice were treated for 9 days and challenged on day 3 by exposure to mosquitoes infected with Plasmodium berghei. Treatment doses ranged between 200 and 400mg/kg/day, corresponding approximately to the dosage applied by traditional healers to cure malaria patients or prevent the disease. Parasitemia reduction in treated animals was calculated from Giemsa smear counts, of two replicate experiments. To estimate acute toxicity in terms of median lethal dose (LD50), geometrically increasing doses were administered to mice. Sub-acute toxicity of the herbal combination (KA) was investigated by administering the same doses as in the antiplasmodial activity test for a period of 14 days, followed by 14 days of recovery observation. Locomotor activity (Open Field Test), body weight, liver and kidney morphology were monitored. The combination KA was found to exhibit antiplasmodial activity in the murine malaria model. In mice treated with the combination remedy at a dosage of 200mg/kg/day, parasitemia values of 6.2%±1.7 and 6.5%±0.8 were recorded, compared to 10.8%±1.3 and 12.0%±4.0 in controls (p