Effects of caffeine on oxidant-antioxidant mechanisms in the rat liver

Objective: Caffeine (1, 3, 7-trimethylxanthine) is a purine alkaloid which exists in a variety of foods and drinks. Today, caffeine is a regularly consumed substance, found in coffee, tea, chocolate and cola. The main aim of our study was to compare the potential antioxidant effects of oral caffeine intake in rat the liver at two different doses over a short period of time. Methods: We measured malondialdehyde (MDA) levels, which is a product of lipid peroxidation, in rat livers following caffeine administration. In addition, we evaluated superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and glutathione S transferase (GST) activities as well as glutathione (GSH) levels in the liver. Thirty male Wister rats were used. Rats were equally divided into three groups. Group 1 was the control group, Group 2 received 30 mg/kg of caffeine and Group 3 received 100 mg/kg caffeine (non-toxic high dose) orally for 14 days (a short time period). Results: Our results showed that the 30mg/kg and 100 mg/kg caffeine doses decreased lipid peroxidation in liver. Antioxidant enzyme activities in the rat liver, like SOD, catalase, GPx and GST, showed a statistically significant increase with caffeine intake. Liver glutathione levels, in comparison to the control group, showed a slight increase, but this was not statistically significant. Results from the Spearman analysis showed a strong negative correlation between MDA levels and GPx, GST and SOD activities. Tissue GST activity and tissue catalase activity showed a strong positive correlation. Conclusion: Decreased lipid peroxidation and increased antioxidant enzyme activities demonstrate improved control of oxidative stress, suggesting that these doses of caffeine may have antioxidant activity. ©Copyright 2012 by Gazi University Medical Faculty