Aqueous preparations of the whole plant of Tapinanthus dodoneifolius (DC) Danser growing on Parkia biglobosa tree are used by the nomads in Northern part of Nigeria for managing malaria, and many other ailments example, diabetes, fever, diarrhoea and wounds. To date, there are no efficacy or safety studies carried out to support its ethno-medicinal use in malaria management. This study aims to investigate the pharmacological activity of the plant relevant to the symptomatic treatment of malaria. High-performance liquid chromatography (HPLC) fractionation of methanol extract of Tapinanthus dodoneifolius (MCETD) produced six fractions (TDF1 –TDF6). Three concentrations of the MCETD (100, 200 and 400 mg/kg body weight); and TDF3 (25, 50 and 100 mg/kg) were evaluated for anti-plasmodial activity against Plasmodium berghei parasite in mice using three models: early (suppressive) infection, established (curative) infection and residual (repository, prophylactic) infection. Normal saline and Chloroquine phosphate were used as negative and positive controls respectively. All three models used showed that both the methanol whole plant extract of T. dodoneifolius and TDF3 fraction produced significant (p< 0.01) and dose-dependent chemo-suppressive effect when compared with the negative control group. They also produced a reduction in parasite count and a significant (p< 0.01) and dose-dependent increase in the survival times of the infected mice as compared to the negative untreated group. The phytochemical analysis revealed the presence of carbohydrate, tannins, flavonoids, anthracene, cardiac glycosides, saponin glycosides, steroid and triterpenes. The oral and intraperitoneal medium lethal doses (LD50) were estimated to be greater than 5000 mg/kg and 3800 mg/kg respectively. The results suggest the presence of pharmacologically active constituents in the extract with anti-plasmodial activity against Plasmodium berghei that justifies its use in malaria ethno-medicine.
Key words: Tapinanthus dodoneifolius, Plasmodium berghei, anti-plasmodial activity, ethno-medicine, malaria.
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