Rauwolfia Vomitoria and Vitamin E Restore Impaired Learning and Memory in 3-Nitropropionic Acid-Induced Oxidative Stressed Mice

The effect of root bark extract of Rauwolfia vomitoria (RV) and Vitamin E on neurobehaviour in 3-nitropropionic acidinduced oxidative stress (OS) in mice was evaluated. Forty mice were divided into four groups (1-4) of 10 mice each. Animals in group one (control rats) received placebo treatment. Animals in group two were induced into oxidative stress by intraperitoneal injection (i.p) with 20 mg/kg body weight of 3-nitropropionic acid (3NP) once daily for 5 days. Animals in group three were pre-treated orally with 16 mg/kg body weight of root bark extract of R. vomitoria before being treated with 20 mg/kg body weight of 3NP (i.p) for 15 days. Animals in group four were pre-treated orally with 10mg/100g of Vitamin E (VE) before being treated with 20 mg/kg body weight of 3NP (i.p). The Morris water maze (MWM) test was done to determine the learning and memory status of the mice. There was significant (P<0.05) longer swim latencies particularly for days 2 and 3 of the acquisition training in the 3NP-induced oxidative stress group of mice when compared to the control group, RV treated 3NP OS group and vitamin E treated 3NP OS group. Findings from the reversal training swim latency, acquisition quadrant, retention quadrant duration, annulus acquisition frequency, frequency of annulus reversal and visible platform task showed a significant increase (P <0.05) in the swim latency of RV+3NP OS group when compared with the control and the VE+3NP OS group and a decrease in 3NP OS when compared with the VE+3NP OS and the control group. Treatment of these 3NP-induced oxidative stressed mice with root bark extract of R. vomitoria and Vitamin E reversed this cognitive learning and memory impairments toward normal, with R. vomitoria being more potent in ameliorating the effect of oxidative stress on learning and memory.