Acute and sub-chronic toxicity screening of aqueous and ethanolic extracts of Corynanthe pachyceras K. Schum (Rubiaceae), a Sub-Sahara African aphrodisiac plant

Abstract

Objective: This study investigated the acute and sub-chronic toxicities of the aqueous (AE) and ethanolic extract (EE) from Corynanthe pachyceras. Methods: Acute and sub-chronic toxicity tests were carried out following the 425 and 407 Organization for Economic Cooperation and Development (OECD) guidelines respectively. For the acute toxicity study, mice were randomly divided into groups treated with a single dose of distilled water (10 ml/kg) or the single reference dose (2000 mg/kg) of aqueous or ethanolic extract of C. pachyceras. Lethal dose 50 (LD50) was determined after 24h. Mice were individually checked for any toxicity sign and mortality over a 14-day period. For the sub-chronic toxicity study, young rats orally received repeated doses of each extract (50, 150 or 450 mg/kg) during 28 days. Body weight was taken every 2 days. After sacrifice, organ weights, hematological, biochemical and histopathological markers were measured. Results: The LD50 of C. pachyceras extracts was found to be greater than 2000 mg/kg in the acute toxicity study. In the sub-chronic toxicity test, males receiving the high dose (450 mg/kg) of both extracts significantly showed an increase (P<0.05-0.001) in immune cells. In rats treated with the low (50 mg/kg) and medium (150mg/kg) doses of the ethanolic extract of C. pachyceras, activity of ALAT and, concentrations of direct bilirubin, creatinine and total cholesterol were significantly increased (P<0.05-0.0001) when compared with control rats. C. pachyceras extracts did not alter the histology of the vital organs studied. Conclusion: C. pachyceras can be considered as non-toxic, but low doses are recommended to avoid possible chronic side effects.