Protective Effect of Silymarin on Monosodium Glutamate-induced Liver Toxicity in Rats

Monosodium glutamate (MSG) is a food additive with potential hepatotoxic effect. Silymarin (SIL) has promising liver protective activity. This study assessed the protective effect of SIL on MSG-induced liver toxicity in rats. Thirty adult Wistar rats (180 -200 g) were grouped into 6 of 5 rats/group. The rats were orally treated for 14 days as follows: Group 1 (Control: Distilled water), group II (MSG; 600 mg/kg/day) and group III (SIL; 200 mg/kg/day). Groups IV-VI were supplemented with SIL (50, 100 and 200mg/kg/day) before treatment with MSG (600 mg/kg/day). On day 15, blood samples were collected for liver function marker investigations. Liver samples were weighed and analysed for oxidative stress markers and histology. MSG significantly (p< 0.01) increased body and liver weights (p< 0.01) serum gamma-glutamyl transferase, alkaline phosphatase, amino transferases, lactate dehydrogenase, bilirubin and liver malondialdehyde levels when compared to the control. Glutathione, superoxide dismutase, catalase, and glutathione peroxidase levels were significantly (p< 0.001) decreased by MSG when compared to control. MSG caused hepatocyte necrosis. However, SIL supplementation restored body and liver weights at 50 mg/kg (p< 0.05), 100 mg/kg (p< 0.01) and 200 mg/kg (p< 0.01) when compared to MSG. SIL supplementation restored the aforementioned biomarkers at 50 mg/kg (p< 0.05), 100 mg/kg (p< 0.01) and 200 mg/kg (p< 0.001) when compared to MSG. Liver structure was restored by SIL supplementation. It was concluded that SIL protects against MSG-induced liver toxicity in a dose-related fashion.