Effects of coffee powder supplementation on the blood glucose and antioxidative enzyme activity of liver tissue in STZ-induced diabetic rats

Abstract

Purpose: The purpose of this study was to evaluate the role of coffee in diabetic rats in order to prevent hyperglycemia and hyperlipidemia, and to improve antioxidant enzyme activity in streptozotocin induced diabetic rats. Methods: Thirty two male Sprague-Dawley rats (body weight 200 ± 5 g) were divided into two groups; diabetic and nondiabetic groups. The groups were each randomly divided into two subgroups; fed control and coffee (5 g coffee powder/㎏ diet) diets. Diabetes was induced by intramuscular injection of 50 mg streptozotocin/kg body weight. Rats with blood glucose concentrations ≥ 300 ㎎/dL were considered diabetic for these experiments. All rats were fed an experimental diet and deionized water ad libitum for 4 weeks. Results: The results of this study indicate that body weight gain was significantly lower in diabetic groups than in nondiabetic groups regardless of diet. Mean food intake was significantly higher in diabetic groups than in nondiabetic groups, and significantly higher in the coffee group than in the control group in diabetic rats. Food efficiency ratio (FER) was significantly lower in diabetic groups than in nondiabetic groups regardless of diet. The fasting blood glucose of coffee supplemented groups was significantly lower compared with the control group in diabetic and nondiabetic rats. The levels of serum LDL-cholesterol and atherogenic index were significantly lower in the coffee group than in the control group in diabetic and nondiabetic rats, and serum HDL-cholesterol was significantly higher in the coffee group than in control groups. The contents of hepatic triglyceride were significantly lower in the coffee group than in the control group in diabetic and nondiabetic rats. The lipid peroxidation of malondialdehyde (MDA) contents was significantly lower in the coffee group than in the control group in diabetic and nondiabetic rats. Activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase in liver was not significantly different by experimental diets among all groups. Conclusion: In conclusion, effects of 0.5% coffee powder supplemented diet were beneficial on blood glucose and lipids in diabetic rats.