Chemoprotective effects of ethanolic extract of neem leaf against MNNG-induced oxidative stress.

We evaluated the modifying effects of ethanolic extract of neem leaves (Azadirachta indica A. Juss) on oxidative stress induced by the potent gastric carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in male Wistar rats. The extent of lipid peroxidation and the status of the antioxidants superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were used as intermediate endpoints of chemoprevention. Three different concentrations of ethanolic neem leaf extract (100, 200 and 400 mg kg(-1) body weight) were administered by intragastric intubation (i.g) for five consecutive days followed by MNNG (i.g) 1.5 h after the final administration. Enhanced lipid peroxidation was accompanied by compromised antioxidant defences in the stomach, liver and erythrocytes of MNNG-treated rats. Pretreatment with ethanolic neem leaf extract at a dose of 200 mg/kg body weight (bw) significantly lowered the concentration of lipid peroxides and increased antioxidant levels. Our results demonstrate that neem leaf exerts its chemoprotective effects on MNNG- induced oxidative stress by decreasing lipid peroxidation and enhancing the antioxidant status.