Toxicity and nutritional studies on Mucuna pruriens leaves from Nsukka, South-Eastern Nigeria

Nutrient, proximate and phytochemical analyses of Mucuna pruriens leaves were done. Acute and sub-acute toxicity studies on the methanol extract were done. Eighteen rats dosed with the extract at 10, 100, 1000, 1600, 2900 and 5000 mg/kg body weights were used for acute toxicity test. For the sub-acute toxicity study, 24 rats randomly allotted into four groups (A–D) of six animals each were used. Graded doses (100, 200, 400 mg/kg) of the extract were administered orally to groups A, B and C, respectively, for 28 days. Group D was the untreated control. Body weight changes, gross and histopathological examinations were carried out on the lungs, liver, brain, heart, spleen, testes and kidneys. The dried leaves contained 29.77% crude protein, vitamins A, C, E, B6, B9, B12, iron, copper and zinc. Anti-nutrients found were phenols, hydrogen cyanide, tannins, oxalate, saponin and anthocyanin. Alkaloids, terpenes and flavonoids were detected. The LD₅₀ was >5000 mg/kg. Cytotoxic oedema of neurons, myocardial haemorrhages with hypertrophy of cells, perihepatic fibrinous exudation with haemorrhages and necrosis in liver, inflammation and hyperplasia of lungs, reduced spermatids and glomerulonephritis with hypercellularity of glomerulus were observed on histopathology. Leaves of M. pruriens, though nutritionally rich, contain potentially toxic principles and anti-nutrients which may have been responsible for widespread signs of toxicity in the brain, lungs, heart, testes, liver and kidneys of rats dosed at 400 mg/kg body weight of the extract for 28 days.