Renoprotective and antioxidant effects of Saururus chinensis Baill in rats fed a high-fructose diet

This study investigated the preventive effect of Saururus chinensis Baill against renal damage induced by a high-fructose diet in rats. The rats (n = 30) were fed either a cornstarch-based (65%), high-fructose (65%), or high-fructose (64.5%) diet with 0.5% S. chinensis Baill extract for 10 weeks. Twenty-four hour urine collections were obtained and the animals were sacrificed after an overnight fast. Serum urea and creatinine and urine albumin were measured using colorimetric methods, and creatinine clearance was determined. In addition, thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), and the activity of superoxide dismutase (SOD) in the kidney were determined. Kidney samples were also examined histologically. The fructose-fed rats showed renal dysfunction, indicated by decreased creatinine clearance, increased albumin in the urine, and increased urea and creatinine in the serum. These renal function parameters were comparable to control levels in rats that consumed S. chinensis Baill. Fructose consumption increased renal TBARS and reduced GSH and SOD activity, whereas these levels were near-normal in the rats consuming S. chinensis Baill. The kidneys of fructose-fed rats showed glomerular basement membrane thickening, mesangial matrix expansion, and tubule dilation. These pathological changes were not seen in the rats that consumed S. chinensis Baill. Therefore, S. chinensis Baill effectively alleviated fructose-induced renal damage in these rats, at least partially due to antioxidant activity.

Hypoglycemic and hypolipidemic effects of Saururus chinensis Baill in streptozotocin-induced diabetic rats

Saururus chinensis Baill was reported to inhibit alpha-glucosidase in vitro and flatten postprandial increase in blood glucose in streptozotocin (STZ)-induced diabetic rats. We studied the effect of chronic consumption of S. chinensis Baill on blood glucose and lipid profile in STZ-induced diabetic male rats fed high fat diet. Male rats weighing 100-120 g were fed 30% fat diet with and without 10% freeze-dried leaves of S. chinensis Baill for 7 weeks after 1 week of adaptation. The rats were rendered diabetic by intravenous injection of STZ (60 mg/kg) after 6-week feeding of the assigned diets. At 1 week after the injection, the rats were sacrificed after an overnight fast. Plasma glucose (380.2 +/- 14.4 mg/dL), total cholesterol (93.9 +/- 7.9 mg/dL) and triglyceride levels (123.6 +/- 7.5 mg/dL) of the S. chinensis Baill group were significantly lower than those of the control group (418.1 +/- 12.0 mg/dL, 119.9 +/- 9.4 mg/dL, 152.0 +/- 10.3 mg/dL, respectively, p<0.05). Chronic consumption of S. chinesis Baill significantly decreased maltase activity of the small intestinal mucosa (120.1 +/- 8.7 U/g protein) compared with the control group (96.8 +/- 7.0 U/g protein, p<0.05). These results suggest that S. chinensis Baill have hypoglycemic and hypolipidemic effects by inhibiting alpha-glucosidase activity in the animal model of diabetes mellitus.