Antimalarial, toxicity and phytochemicals evaluation of lippia kituiensis and cucumis metuliferus species found in Tanzania

Abstract

This study aimed at evaluating the antimalarial, toxicity and phytochemical profile of Cucumis metuliferus and Lippia kituiensis used for treatment of malaria in Tanzania. Pulverised plant materials were sequentially extracted in chloroform, ethyl acetate and methanol, the solvent was removed using a rotary evaporator. This extracts were evaluated for antimalarial activity using animal model infected with Plasmodium berghei. The negative and positive controls were treated with 1% DMSO and chloroquine (CQ) respectively. Cucumis metuliferus percentage suppression was 98.55%, 88.89% and 84.39% for chloroform, methanolic, and ethyl acetate extract respectively. For L. kituiensis the percentage suppression was 95.19%, 93.88% and 74.83%, for ethyl acetate, chloroform and methanolic extracts respectively at a dose of 1500, 600 and 300 mg/kg respectively. Phytochemical profile of C. metuliferus and L. kituiensis methanolic, ethyl acetate and chloroform leaf extract were also determined by GCMS

technique. The analysis revealed the presence of 11 major compounds. Moreover, the extracts were evaluated for acute and sub-acute toxicity. In acute toxicity test, the result showed no significant difference was observed in behavior, body weight and hematology parameters. The LD 50 of the C. metuliferus and L. kituiensis extracts in mice was determined to be not greater than 2000 mg/kg body weight. In sub acute toxicity the rats were orally treated with doses of 150 mg/kg, 300 mg/kg and 500 mg/kg body weight. The results revealed a significant change in body weight, organ weight, hematological and biochemical parameters of rats administered with 300 mg/kg and 500 mg/kg body weight. Histopathological examination revealed the distraction of glomerula and bowman’s capsule, distraction of tubules and inflammation of kidneys and bile duct hyperplasia, hepatic necrosis and vacuolation of the liver while the lung showed thickened alveolar wall in a dose of 300 mg/kg and 500 mg/kg body weight. These findings suggest that C. metuliferus and L. kituiensis have demonstrated antimalarial activities, but with toxicity. To reduce their toxicity and improve their pharmacologic properties, the study suggests that isolation, characterization, structural elucidation of different types of bioactive compound with high potency may serve as candidate to reduce their toxicity effect and hence developing a new beneficial drug.