Postprandial hypoglycemic effect of mulberry leaf (Morus alba L.) was compared in two animal models: Goto-Kakizaki (GK) rats, a spontaneous non-obese animal model for type II diabetes, and their counterpart control Wistar rats. First, the effect of a single oral administration of mulberry leaf aqueous extract (MLE) on postprandial glucose responses was determined using maltose or glucose as substrate. With maltose-loading, MLE reduced peak responses of blood glucose significantly in both GK and Wistar rats (P < 0.05), supporting the inhibition of α-glucosidase by MLE in the small intestine. With glucose-loading, MLE also significantly reduced blood glucose concentrations, measured at 30 min, in both animal models (P < 0.01), proposing the inhibition of glucose transport by MLE. Next, dried mulberry leaf powder (MLP) was administered for 8 weeks by inclusion in the diet. By MLP administration, fasting blood glucose was significantly reduced at weeks 4 and 5 (P < 0.05), but then returned to values that were similar to those of the control at the end of experimental period in GK rats. Insulin, HOMA-IR, C-reactive protein, and triglycerides tended to be decreased by MLP treatment in GK rats. All other biochemical parameters were not changed by MLP administration in GK rats. Collectively, these findings support that MLE has significant postprandial hypoglycemic effect in both non-obese diabetic and healthy animals, which may be beneficial as food supplement to manage postprandial blood glucose. Inhibitions of glucose transport as well as α-glucosidase in the small intestine were suggested as possible mechanisms related with the postprandial hypoglycemic effect of MLE.

This study was performed to investigate the effect of chlorella on cadmium (Cd) toxicity in Cd- administered rats. Sixty male Sprague-Dawley rats (14 week-old) were blocked into 6 groups. Cadmium chloride was given at levels of 0 or 325 mg (Cd: 0, 160 ppm), and chlorella powder at levels of 0, 3 and 5%. Cadmium was accumulated in blood and tissues (liver, kidney and small intestine) in the Cd-exposed groups, while the accumulation of Cd was decreased in the Cd-exposed chlorella groups. Fecal and urinary Cd excretions were remarkably increased in Cd-exposed chlorella groups. Thus, cadmium retention ratio and absorption rate were decreased in the Cd exposed chlorella groups. Urinary and serum creatinine, and creatinine clearance were not changed in experimental animals. In addition, metallothionein (MT) synthesis in tissues was increased by Cd administration. The Cd-exposed chlorella groups indicated lower MT concentration compared to the Cd-exposed groups. Moreover, glomerular filtration rate (GFR) was not changed by dietary chlorella and Cd administration. According to the results above, this study could suggest that Cd toxicity can be alleviated by increasing Cd excretion through feces. Therefore, when exposed to Cd, chlorella is an appropriate source which counteracts heavy metal poisoning, to decrease the damage of tissues by decreasing cadmium absorption.

The aim of this study was to examine the effect of leucine on body weight and carbohydrate metabolism in 6 month‐old Sprague‐Dawley (n=80) rats. One group of 10 rats was fed control diet (control group) and another group of 70 rats was fed a high‐fat diet for 14 wks (high‐fat group) to induce obesity. Ten rats of each group were killed at this stage and the remaining obese rats were fed with one of six experimental diets containing 4%, 20% (w/w), two dietary fat levels (C‐, H‐) and three different Leu levels ; 0g, 0.6g, 1.2g /kg BW (‐LO, ‐LL, ‐LH) for 5 wks. Food intake, body weight, adipose tissues and organ weights were measured. To examine carbohydrate metabolism, oral glucose tolerance test (OGTT) conducted and the area under the curve (AUC) of each group was calculated. Body weight were significantly reduced in 1.2g/kg Leu groups (CLH, HLH) than 0g/kg Leu groups (CLO, HLO). Perirenal fat pad weights of 0g/kg Leu groups (CLO, HLO) were significantly higher than those of 0.6g/kg Leu groups (CLL, HLL) and those of 1.2g/kg Leu groups (CLH, HLH). AUC of 1.2g/kg Leu groups (CLH, HLH) were significantly lower than 0g/kg Leu groups (CLO, HLO). In conclusion, Leu administration might have weight loss effect and improve carbohydrate metabolism in dietary fat‐induced obese rats. * This work was supported by Sungshin Cement Co., Ltd. of Seoul, Korea and the second stage of the Brain Korea 21 project in 2008.