Pharmacological evaluation of Ipomoea asarifolia (Desr.) against carbon tetrachloride-induced hepatotoxicity in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Ipomoeaasarifolia (Desr.) Roem. and Schult. is used traditionally in some parts of Africa for the treatment of a variety of diseases. This study attempts to validate its hepatoprotective activity by evaluating the prophylactic and curative properties of the methanolic extract of Ipomoea asarifolia (IA) leaves. MATERIALS AND METHODS: Liver damage was induced by administering 0.5 ml/kg of an equal mixture of carbon tetrachloride (CCl(4)) in olive oil intraperitoneally on alternate days, for 5 days and the plant extract was given orally daily, for 7 days at doses of 100, 200 and 400 mg/kg. RESULTS: Pre-treatment with the extract significantly (P<0.05) decreased CCl(4)-induced elevation in serum levels of alanine transaminase, aspartate transaminase, alkaline phosphatase, triglycerides, bilirubin and cholesterol, better than the standard drug silymarin at 100 mg/kg. In the curative study, IA significantly (P<0.05) reversed CCl(4)-induced liver damage, comparable to silymarin. Hepatoprotective potential was further supported by decrease in pentobarbitone sleeping time and improved hepatic tissue histopathology. CONCLUSION: These results indicate that I. asarifolia leaves have potent hepatoprotective activity against CCl(4)-induced hepatic damage in rats.

Antagonistic antimalarial properties of pawpaw leaf aqueous extract in combination with artesunic acid in Plasmodium berghei-infected mice.

BACKGROUND & OBJECTIVES: Artemisinins, the main stay in the treatment of malaria are used in combinations with other antimalarials to forestall resistance, as artemisinin-combination therapies (ACTs). However, ACTs are expensive and some of the non-artemisinin components are not well-tolerated by patients. There are several folkloric and scientific proofs of the efficacy of herbal remedies for malaria. Mature leaves of Carica papaya is widely used to treat malaria in several African countries. An ACT involving a medicinal herb extract or its active constituent(s) will provide an indigenous alternative/herbal ACT. METHODS: Mature fresh leaves of Carica papaya were grounded and macerated in cold distilled water for 24 h and the extract (PCE) was stored in the refrigerator for seven days. Fresh extracts were made as needed. The antiplasmodial activity of PCE and/or artesunic acid were determined by using the Peter's 4-day suppressive test in Plasmodium berghei-infected mice. The ED50 and ED90 were calculated from the dose-response relationships. RESULTS: The combination of 50 mg/kg of PCE and 15 mg/kg of artesunic acid produced a significant reduction of parasitemia (81.25%), compared to 50 mg/kg PCE alone (37.7%). The mean survival time of the combinations of PCE and 15 mg/kg of artesunic acid, and PCE alone followed a dose-dependent manner. The ED50 of PCE showed that it has a very good activity. The isobolar equivalent (IE) calculated from the ED90 of PCE in combination with artesunic acid showed that the interaction was antagonistic. INTERPRETATION & CONCLUSION: Although pawpaw alone was found to have a very good activity, its combination with artesunic acid is antagonistic. Combinations of artemisinins and pawpaw show little promise for combination therapy development.