Acute and subchronic toxicological assessment of Byrsocarpus coccineus Schum. and Thonn. (Connaraceae) leaf aqueous extract

Background: The leaf aqueous extract of Byrsocarpus coccineus (BC) administered orally has shown great promise as a phytotherapeutic agent based on results of pharmacological investigations. In view of the importance of toxicological evaluation in drug development, the aim of this study was to test the extract for acute and subchronic effects.

Methods: In the acute toxicity test, mice were administered p.o. with BC up to 10g/kg and i.p. at doses of 50–800mg/kg. Animals were then observed for behavioural changes, signs of toxicity, and mortality within 24h. In the subchronic toxicity test, rats were daily treated with BC at doses of 40, 200, and 1000mg/kg p.o., for 30 and 60 days. Control animals received distilled water. Animals were weighed at 7 days interval and monitored for feeding and drinking habits. At the end of the test periods, haematological, biochemical, and urinary parameters were determined and vital organs macroscopically examined and weighed.

Results: In the acute toxicity test, BC was practically non-toxic showing no mortality and visible signs of toxicity. The LD₅₀, given i.p., was 158.4mg/kg. Administered for 30 days, BC did not produce any significant (P<0.05) deleterious effect on haematological and biochemical parameters and vital organs. In the 60 day study, BC elicited significant increases in platelet and WBC count and reductions in levels of liver enzymes (AST, ALT, and ALP), total cholesterol, HDL, triglycerides, and total protein. The weight of some vital organs were significantly affected but with comparable macroscopy to control. Generally, BC did not significantly affect feeding and drinking habits, body weight, and urinary parameters.

Conclusion: Results obtained in this study suggest that the leaf aqueous extract of Byrsocarpus coccineus is safe when administered orally with potential long-term beneficial effects as immunostimulant, hepatoprotective, hypolipidemic, and antiatherogenic agent.