BackgroundQuercetin derivatives in onions have been regarded as the most important flavonoids to improve diabetic status in cells and animal models. The present study was aimed to examine the hypoglycemic and insulin-sensitizing capacity of onion peel extract (OPE) containing high quercetin in high fat diet/streptozotocin-induced diabetic rats and to elucidate the mechanism of its insulin-sensitizing effect.MethodsMale Sprague-Dawley rats were fed the AIN-93G diet modified to contain 41.2% fat and intraperitoneally injected with a single dose of streptozotocin (40 mg/kg body weight). One week after injection, the rats with fasting blood glucose levels above 126 mg/dL were randomly divided into 4 groups to treat with high fat diet containing 0 (diabetic control), 0.5, or 1% of OPE or 0.1% quercetin (quercetin equivalent to 1% of OPE) for 8 weeks. To investigate the mechanism for the effects of OPE, we examined biochemical parameters (insulin sensitivity and oxidative stresses) and protein and gene expressions (pro-inflammatory cytokines and receptors).ResultsCompared to the diabetic control, hypoglycemic and insulin-sensitizing capability of 1% OPE were demonstrated by significant improvement of glucose tolerance as expressed in incremental area under the curve (P = 0.0148). The insulin-sensitizing effect of OPE was further supported by increased glycogen levels in liver and skeletal muscle (P < 0.0001 and P = 0.0089, respectively). Quantitative RT-PCR analysis showed increased expression of insulin receptor (P = 0.0408) and GLUT4 (P = 0.0346) in muscle tissues. The oxidative stress, as assessed by superoxide dismutase activity and malondialdehyde formation, plasma free fatty acids, and hepatic protein expressions of IL-6 were significantly reduced by 1% OPE administration (P = 0.0393, 0.0237, 0.0148 and 0.0025, respectively).ConclusionOPE might improve glucose response and insulin resistance associated with type 2 diabetes by alleviating metabolic dysregulation of free fatty acids, suppressing oxidative stress, up-regulating glucose uptake at peripheral tissues, and/or down-regulating inflammatory gene expression in liver. Moreover, in most cases, OPE showed greater potency than pure quercetin equivalent. These findings provide a basis for the use of onion peel to improve insulin insensitivity in type 2 diabetes.

In this study, we compared corn gluten hydrolyzates, BCAAs, and leucine for their effects on body weight reduction in high fat-induced obese rats in order to determine the major active components in the corn gluten hydrolyzates. After obesity was induced for 13 weeks with high fat diet, the overweight-induced SD rats (n = 64) were stratified according to body weight, randomly blocked into eight treatments, and raised for 8 weeks. Four groups were changed to a normal diet and the other groups remained on the high fat diet. Each of the groups within both diets was fed either casein, corn gluten hydrolyzates, leucine, or branched chain amino acids, respectively. Daily food intake, body weight gain, and food efficiency ratio were significantly lower in the corn gluten hydrolyzate groups compared to the other groups, regardless of the high fat diet or normal fat diet. The rats fed the corn gluten hydrolyzates diet had the lowest perirenal fat pad weights whereas muscle weight was significantly increased in the corn gluten hydrolyzates groups. Plasma triglyceride, hepatic total lipid, and total cholesterol contents were significantly reduced in the corn gluten hydrolyzates groups. Other lipid profile measurements were not significantly changed. Plasma triglyceride and hepatic total lipid were also significantly reduced in the BCAA and leucine groups. Leptin levels were significantly lower and adiponectin was significantly higher in the corn gluten hydrolyzates groups. Fasting blood glucose, insulin, C-peptide, and HOMA-IR levels were also significantly reduced in the corn gluten hydrozylates groups, regardless of fat level.

Metabolic syndrome (MetS) has become a global epidemic. In particular, it is known that there is a dramatic increase in the prevalence of MetS among women during the postmenopausal period. Recently, accumulating studies have suggested that vitamin D deficiency may be inversely associated with the risk factors regarding MetS. However, evidence from postmenopausal women is limited. In this study, we examined the association between the serum 25-hydroxyvita-

Alcohol hangover is an unpleasant aftermath of heavy alcohol drinking. Hangover onset starts after the oral administration of alcohol since ethanol, a key component of the alcoholic drinks, metabolized to acetaldehyde. In this study, we investigated whether the supplement formula might improve the alcohol metabolism in healthy adult men. In a double‐blinded, randomized, crossover study, subjects were received yeast extract mixtures (YEM, n=21), Hovenia Dulcis mixtures (HDM, n=21), placebo (PLC, n=21), and control (CON, n=21) in separate 4 week supplementation periods at a single oral dose followed by one week washout periods. At each visit (0, 1, 2, 3, 4 weeks), the subjects drank 450 mL 23 % alcohol simultaneously with mixtures and blood was drawn periodically (0, 0.25, 0.5, 1, 2, 4, 6, 15 hr). Fifteen subjects completed the protocol and included in the analysis. The plasma ethanol concentrations were tended to lower in the YEM (10 %) and the HDM (5 %) groups. The area under the curves (AUCs) and Cmax for plasma ethanol were significantly decreased only in the YEM group, when compared with the CON group. The AUCs and Cmax for plasma acetaldehyde concentration were significantly decreased in the YEM (45 % and 54 %) and the HDM (35 % and 53 %) groups respectively, when compared with PLC (P<0.01). These findings demonstrated that alcohol metabolism and hangover syndromes might improve by YEM than HDM.

This study was performed to investigate the effect of corn gluten hydrolysates, which contains high branched amino acid (BCAA) especially leucine, on weight reduction. To induce overweight, 8 weeks old male Sprague Dawley rats (n=80) were divided into two groups. One group (n=8) was fed normal fat diet (16.9% energy from fat) and the other group (n=72) was fed high fat diet (60.0% energy from fat) for 13 weeks. After 13 weeks, we sacrificed normal fat diet group (n=8) and some of high fat diet group (n=8) for the identification of overweight. The overweight was confirmed by body weight, fat pad weight, plasma lipid concentration and some hepatic enzyme activities. After then high fat diet group was randomly divided into 8 groups according to their fat levels (16.9% or 60% energy from fat) and kinds of treatment (casein, corn gluten hydrolysates, leucine or BCAA). Body weights were measured once a week and food intake was measured three times a week during experimental period. The body weight and fat pad loss in the corn gluten hydrolysates were higher than other groups regardless their fat intake. Leucine group was tended to gain less weight than control group. In conclusion, ingestion of corn gluten hydrolysates has a weight loss effect in high fat diet‐ induced obese rats. This study suggests that corn gluten hydrolysates can be available for reducing body weight as a functional food.