American Journal of Research in Medical Sciences. 2018; 3(1):(19-42)
Acute and sub-chronic oral toxicity studies on methanol leaf extract of Gnetum africanum Welw in wistar rats
Nkeiruka Emmanuela Udeh, Aruh Anaga, Isaac Uzoma Asuzu
Method: Gnetum africanum leaves were identified by a plant taxonomist, air-dried, pulverized, and extracted with 80% methanol for 48 hours in July 2015. The extract was concentrated in-vacuo and stored as Gnetum africanum extract (GAE) at 4°C. Thirty-five male albino rats randomly divided into seven groups (n = 5) were used for acute toxicity test, which was done in August 2015. Rats in groups 1–6 were given GAE at 500, 1,000, 2,000, 3,000, 4,000 and 5,000 mg/kg, respectively, while group 7 rats received 10 ml/ kg distilled water. Feed and water were provided and they were observed for signs of toxicity for 48 hours. A 90-day subchronic toxicity study was conducted using 56 rats of four groups (n = 14) in December 2015–March, 2016. Group 1 received feed without GAE, while groups 2–4 were given feed with GAE at 10, 20 and 40 mg/kg respectively. Four rats from each group were bled on days 30, 60, and 90 for clinical biochemistry and sacrificed for histopathological examination.
Result: The median lethal dose (LD50) was greater than 5,000 mg/kg while no-observed- adverse-effect-level was 40 mg/kg. Serum marker enzymes and creatinine were not increased in rats given extract in feed, while there were no histopathological lesions in the organs studied.
Conclusions: The extract is safe at both the acute and subchronic levels.