Acute and Chronic Toxicity Studies of Ethanol Leaf Extract of Merremia Tridentata (Linn) Hallier F.

The acute and chronic toxicity evaluation of Ethanol leaf extract of Merremia tridentata (Linn) Halier F. (MTELE) was carried out on albino wistar rats. Phytochemical screening and acute toxicity profile of the extract were determined using standard methods. The animals were assigned into groups and administered varying doses of MTELE (100, 200, 400 mg/kg body weight and 0.2 ml of distilled water) for a period of hundred days (fourteen weeks). The body weight, relative organ weight, haematology, serum biochemical indices and histopathological studies of the liver, kidney, spleen, heart, and lungs were appropriately carried out to determine propensity of possible toxicity. Phytochemical screening revealed the presence of alkaloids, tannins, cardiac glycosides, saponins, steroids, triterpenes, flavonoids while anthraquinone and cyanogenic glycosides were absent. The median lethal dose LD₅₀ was estimated as 2200 mg/kg body weight. There was significant (p<0.05) reduction in the percentage change in body weight of rats administered 200 and 400 mg/kg/day dose of the extract for 100days when compared to the control group. Moreover, there was a significant (p<0.05) reduction in the relative weight of the spleen of rats and significant (p<0.05) increase in the relative weight of the liver, kidney, heart and lungs of rats administered 400 mg/kg/day dose. All serum biochemical parameters studied showed significant (p<0.05) increase in group administered 400 mg/kg body weight dose while alkaline phosphatase, aspartate amino transferase, creatine kinase, lactate dehydrogesase and potassium ion showed significant increase (p<0.05) in the group administered 200 mg/kg/day. There is no significant change in hematological parameters like RBC, hemoglobin, hematocrit, platelets, monocytes, basophils, MCV, MCH, MCHC, in the extract treated animals except the lymphocyte that showed a significant (p<0.05) reduction only in the group treated with 400 mg/kg body weight dose. Administration of MTELE at 200 mg/kg body weight did not occasioned any histo-architectural change in the liver and spleen but caused varying degree of remarkable histological derangement in the other tissues. Furthermore, there were remarkable pathologies in the liver, kidney, spleen, heart and lungs ranging from vascular congestion, haemorrhage, fibrosis, to renal and myocardial damage in the group treated with 400 mg/kg/day dose for hundred days. However, 100 mg/kg body weight dose showed no significant difference (p>0.05) in all the parameters evaluated indicating safety at this dosage. Ethanol leaf extract of Merremia tridentata (Linn) Halier F. (MTELE) may not be safe at chronic administration even at dosage as low as 200 mg/kg body weight. The plant should be cautiously employed to avoid unwarranted complication on long term administration.