The Hypoglycemic, Hypolipidemic, and Anti-Diabetic Nephritic Activities of Zeaxanthin in Diet-Streptozotocin-Induced Diabetic Sprague Dawley Rats

Zeaxanthin (ZA), an important compound found in Lycium barbarum, shows various pharmacodynamic effects. In our present study, a high-fat, high-sucrose diet and streptozotocin (STZ)-induced diabetic rat model was used to investigate the antidiabetic activities of ZA. After a 4-week administration of 200 and 400 mg/kg of ZA and 100 mg/kg of metformin hydrochloride, various blood biochemical indexes were detected. ZA strongly normalized the reduced bodyweight and enhanced fasting blood glucose in diabetic rats. The positive data obtained from the oral glucose tolerance test further confirmed its antidiabetic effects. ZA displayed significant hypolipidemic activities indicated by its modulation of serum levels of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and total cholesterol. The antidiabetic nephropathy of ZA was confirmed by its regulation of pathological kidney structures, urine levels of n-acetyl-β-d-glucosaminidase and albuminuria, and serum levels of urea nitrogen. ZA inhibited the serum levels of inflammatory factors including interleukin-2 (IL-2), IL-6, tumor necrosis factor-α, and nuclear factor kappa B, further confirming its renal protection. Moreover, the serum imbalances in superoxide dismutase, glutathione peroxidase, methane dicarboxylic aldehyde, and catalase were normalized by ZA, suggesting its antioxidant properties. Altogether, ZA produced hypoglycemic, hypolipidemic, and antidiabetic nephritic effects in a diet-STZ-induced diabetic rat model.