Effect of Piper longum Linn. in monosodium glutamate toxicity in rats.

Effect of ethanol extract of Piper longum (P. longum) Linn. in monosodium glutamate (MSG) induced toxicity was studied in rats. Oral administration of MSG at a dose of 8 mg/g body weight for 20 consecutive days showed an increase in body weight and liver weight. Oxidative stress was evidenced by significant increase in the level of lipid peroxides and decrease in reduced glutathione (GSH) content of serum, liver and kidney. There was significant increase in serum ALT and AST activities. Level of serum urea increased significantly whereas creatinine level did not altered. Significant increase was also observed in the levels of serum triacylglycerol and total cholesterol. Histopathological examination revealed degeneration and necrosis of hepatocytes, renal tubules and glomeruli of liver and kidney respectively. Rats treated with ethanol extract of P. longum fruits at 300 mg/kg body weight and 600 mg/kg body weight for 14 days significantly decreased body weight, serum triacylglycerol, lipid peroxides in serum, liver and kidney, serum ALT and AST activities and increased the content of GSH in serum, liver and kidney. However, 300 mg/kg body weight was found to be more effective in decreasing the level of triacylglycerol, serum ALT, lipid peroxides in serum, liver and kidney and increasing the content of GSH in serum and liver. Significant reduction in liver weight and serum cholesterol was observed only in rats treated with the extract at this dose. Serum urea level did not vary significantly between treated groups and positive control. Histopathological examination of liver and kidney showed normal histological architecture except for mild congestion. The present study revealed that ethanol extract of fruits of P. longum has antioxidant and hypolipidaemic properties and may be used for treating MSG toxicity.