The hepatotoxic effects of the seeds of Aframomum melegueta (Grains of paradise), a spice were studied in Sprague-Dawley rats. Individual rat groups received sub-chronic exposure of the methanol seed extract at 300 mg/kg for 7, 14 and 21 days respectively. Liver toxicity was evaluated with assay of circulating serum aspartate aminotransferase (AST), alanine aminotransaminase (ALT), alkaline phosphatase (ALP), albumin, total bilirubin concentrations and histopathology of the liver of treated experimental rats. Serum levels of AST significantly (p<0.05) increased progressively in extract-treated rats compared to the control from day 7 till the termination of the study (day 21). However, serum ALT, ALP and total bilirubin levels of test rats were only significantly (p<0.05) elevated relative to the normal on days 14 and 21 of the investigation. The dose (300 mg/kg) of extract produced AST value of 55.8±3 µL -1 while the control was 32.2±1.9 µL . The serum albumin levels of extract-treated rats were however, comparable with that of the normal rats throughout the study period. Histopathology of the rat livers revealed mild focal necrosis of hepatocytes at day 7, moderate multifocal areas of hepatic necrosis at day 14 and severe, diffused necrosis of hepatocytes at day 21 of treatment with the extract. The results demonstrated that the methanol seed extract of A. melegueta was potent in inducing liver toxicity at the tested dose (300 mg/kg). Maximal caution should therefore be imbibed in prolonged excessive use of the plant seeds as spice in delicacies.
This study aims to screen possible antioxidant potentials of methanol extract and polar fractions of Vernonia calvoana leaves and its phytochemical constituents since the leaves are used ethno medically in managing ailments like wounds, blood pressure, inflammation, arthritis, and bone diseases. Dried leaves (900 g) were ground and de-fatted with n-hexane. The dry marc was extracted using 80% methanol and water. Filtrate was concentrated using rotary evaporator at 40°C. Acute toxicity study and phytochemical analysis were performed with crude extract. Fractionation of crude extract using gradient concentrations of methanol and distilled water yielded 4 fractions-F 1 , F 2 , F 3 and F 4. Fractions with the crude were used for in vitro antioxidant studies. From the results, crude extract showed no signs of toxicity in mice at 2000 mg/kg orally. Phytochemical screening showed presence of alkaloids, flavonoids, tannins, phenols, steroids, saponins, terpenes, arthroquinones, carbohydrates and glycosides. The highest percentage antioxidant activity observed with crude extract was 72.37 at 500 µg/ml in DPPH spectrophotometric assay. DPPH results showed percentage antioxidant activity of 81.4% at 500 µg/ml of F 1 and 67.73% at 500 µg/ml of F 2. The FRAP values of the crude extract, F 1 , F 2 , F 3 and F 4 at 500 µg/ml were 1.957, 2.234, 1.731, 1.245 and 1.025 µM respectively. These results showed that the activities of methanol extract of leaves of V. calvoana may be dependent on the concentration of the extracting solvent. Vernonia species are known to contain abundant saponins and flavonoids which are polar compounds and readily soluble in methanol. This may explain the above observed antioxidant activities and thus, the use of the leaves in different traditional curative therapies in Southern Nigeria.
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