Comparative study for the protective effect of silymarin, Eclipta alba extract against high fat diet induce insulin resistance and hyperglycemia in rats

ABSTRACT

This study was designed to show, if the causative role of obesity in the peripheral and hepatic insulin resistance, was through the induction of systemic oxidative stress? and, Can antioxidants alter the natural history of developing diabetes in obese rat model?. Silymarin and Eclipta alba extract [natural flavonoids antioxidant] were used to study their prophylactic effects against high fat diet-induced obesity and develop type II diabetes mellitus in comparison with metformen drug. Fasting blood glucose [BG] and serum insulin [SI] levels, in addition to glucose utilization, insulin resistance [IR] and Beta-cell function were measured as biochemical markers for diabetes mellitus., free fatty acids [FFA], total cholesterol[T-Ch], triglycerides [TG], LDL-C and HDL-C were used as biochemical markers for obesity. Glutathione content [GSH] and superoxide dismutase activity [SOD] were measured as markers for redox homeostasis. Two groups of adult male albino rats were used in this study. The first group was fed with normal standard diet and was served as [-]ve control. The second group were fed with high fat diet for 60 days and divided into five subgroups; G1 rest on high fat diet and served as [+]ve control obese group, while G2, G3, G4 were fed a high fat diet plus silymarin [100 mg/kg]], Eclipta alba extract [75 mg/kg] and metformin [200 mg/kg] respectively, while GS fed beside high fat diet a combined same doses of silymarin and Eclipta alba extract. From the results we concluded that The incidence of type II diabetes mellitus by obesity, through hyperglycaemia, insulin resistance and elevation in lipid parameters and FFAs, are associated with a reduction in Beta-cell function and antioxidant defense mechanisms. 2-The progressive reduction in serum lipids especially FFAs and the increase in antioxidant enzymes may lead to the improvement of the hyperglycemic state after the administration of antioxidants [silymarin and Eclipta alba extract]. 3-Silymarin and Ecltpta alba extract delayed the incidence of obesity induced diabetes mellitus in normal and obese rats due to its ability to protect both the liver and the pancreas against free radicals that were produced by the elevated FFAs levels. 4- Silymarin and Eclipta alba extract in combination have more potent protective effect than each one alone and than that of metformin