ABSTRACT
Aims: Appropriate ratios for combining some African ethnomedicinal plants with proven anti-plasmodial activity were determined with the aim of obtaining herbal remedies with higher efficacies. Place and Duration of the Study: Study was conducted in the Department of Pharmacognosy, Obafemi Awolowo University, Ile-Ife Nigeria. Study Design: Infusions of dried powders of three Nigerian ethnomedicinal plants, Eugenia uniflora leaf, Gongronema latifolium root and stem and Artocarpus altilis stem bark, were separately evaluated and in varied combination ratios for their anti-plasmodial activities Methodology: The infusions were separately prepared, concentrated in vacuo, freeze-dried and evaluated at 400mg/kg against Plasmodium berghei berghei parasites, using the Peter’s four-day chemosuppressive mice model. Normal saline and chloroquine (10mg/kg) were negative and positive controls, respectively. 2- and 3-combinations of the infusions were similarly tested. Results: Of the 2-plant combination ratios, 1:1, 1:3, 2:3 of EG and GA elicited percentage chemo suppressions which were comparable (P=.28; P=.07) to those of the single drugs. Only the EG ratios gave activities that were comparable (P=.28) to the positive control in addition to double survival times and high survivor values by EG 2:3 and GA 1:3. However, those of the EA group, gave relatively low values, barely above 20% with only the ratios 2:3 and 3:2 giving values which were significantly (P=.00) higher than negative control with double survival times. The 3-plant combination ratios, EGA 2:1:2 and 3:3:2 gave suppressions that were significantly (P=.00) higher than the negative control with others but comparable (P=.33) activities to those of the individual drugs. The other ratios with low suppression values were relatively inactive. But three ratios, EGA 3:1:2, 2:1:1, 1:1:1 elicited survival times doubled (204, 242 and 202 %) that of the negative control without commensurate high antiplasmodial activities. Conclusion: Ethnomedicinal antimalarial plants should not be combined without a data of previous scientific evaluations.