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The combination of freeze-dried aronia, red ginseng, ultraviolet-irradiated shiitake mushroom and nattokinase (AGM; 3.4:4.1:2.4:0.1) was examined to evaluate its effects on insulin resistance, insulin secretion and the gut microbiome in a non-obese type 2 diabetic animal model. Pancreatectomized (Px) rats were provided high fat diets supplemented with either (1) 0.5 g AGM (AGM-L), (2) 1 g AGM (AGM-H), (3) 1 g dextrin (control), or (4) 1 g dextrin with 120 mg metformin (positive-control) per kg body weight for 12 weeks. AGM (1 g) contained 6.22 mg cyanidin-3-galactose, 2.5 mg ginsenoside Rg3 and 244 mg β-glucan. Px rats had decreased bone mineral density in the lumbar spine and femur and lean body mass in the hip and leg compared to the normal-control and AGM-L and AGM-H prevented the decrease. Visceral fat mass was lower in the control group than the normal-control group and its decrease was smaller with AGM-L and AGM-H. HOMA-IR was lower in descending order of the control, positive-control, AGM-L, AGM-H and normal-control groups. Glucose tolerance deteriorated in the control group and was improved by AGM-L and AGM-H more than in the positive-control group. Glucose tolerance is associated with insulin resistance and insulin secretion. Insulin tolerance indicated insulin resistance was highly impaired in diabetic rats, but it was improved in the ascending order of the positive-control, AGM-L and AGM-H. Insulin secretion capacity, measured by hyperglycemic clamp, was much lower in the control group than the normal-control group and it was improved in the ascending order of the positive-control, AGM-L and AGM-H. Diabetes modulated the composition of the gut microbiome and AGM prevented the modulation of gut microbiome. In conclusion, AGM improved glucose metabolism by potentiating insulin secretion and reducing insulin resistance in insulin deficient type 2 diabetic rats. The improvement of diabetic status alleviated body composition changes and prevented changes of gut microbiome composition.

The brain is an important modulator of glucose metabolism, and is known to respond Gastrodia elata Blume water extract (GEB). Therefore, we examined whether long-term administration of GEB has hypoglycemic activity, and its action mechanism was explored in partially-pancreatectomized rats that exhibit similar characteristics as Asian type 2 diabetes, non-obese insulin-insufficient diabetes. The rats were provided high-fat diets supplemented with either of (1) 0.5% GEB (GEB-L), (2) 2% GEB (GEB-H), (3) 2% dextrin (control), or (4) 2% dextrin with rosiglitazone (20 mg/kg body weight; positive-control) for eight weeks. GEB dose-dependently improved hypothalamic insulin signaling, enhanced whole-body insulin sensitivity during hyperinsulinemic euglycemic clamp, and reduced hepatic glucose output in a hyperinsulinemic state. GEB dose-dependently increased the area under the curve of the serum insulin levels at the first and second phases during hyperglycemic clamp compared to the control, whereas the positive control had no effect. Insulin sensitivity during the hyperglycemic state also improved, dose-dependently, in response to GEB compared with that of the control, but was less than the positive control. GEB-H increased the mass of β-cells by potentiating proliferation and decreasing apoptosis. In conclusion, GEB could be a therapeutic agent for treating Asian type 2 diabetes.

Objectives: Methyl jasmolate (MeJA)-treated vegetables produce higher concentrations of various bioactive compounds. We investigated whether long-term oral consumption of MeJA-treated and untreated buckwheat sprout powder improves energy, glucose, lipid, and bone metabolism induced by estrogen deficiency in ovariectomized (OVX) rats fed high-fat diets, and explored the mechanisms involved., Methods: OVX rats were divided into four groups and fed high-fat diets supplemented with 3% dextrin (OVX-control), buckwheat sprout powder (BWS), or MeJA-treated buckwheat sprout powder (MJ-BWS) for 12 wk. Sham rats without estrogen deficiency had a control diet as a normal-control., Results: MeJA-treatment increased total polyphenols and flavonoids by about 1.6 fold and isoorientin, orientin, rutin, and vitexin were elevated by about 18% in buckwheat. After 12 wk, OVX rats exhibited increased weight gain, fat mass, skin temperature, hyperglycemia, and decreased bone mineral density (BMD) compared to sham rats. BWS prevented the increase of skin temperature and decrease of femur BMD, but did not improve energy glucose homeostasis as much as MJ-BWS. MJ-BWS prevented increases in body weight and fat mass. Energy expenditure was lowest in OVX-control, followed by BWS, MJ-BWS, and normal-control. Furthermore, MJ-BWS exhibited greater improvements in glucose and insulin tolerance than OVX-control and BWS. Phosphorylation of hepatic Akt and AMPK was potentiated, in ascending order of OVX-control, BWS, MJ-BWS, and normal-control, whereas PEPCK expression was decreased., Conclusions: MJ-BWS prevented and ameliorated the disturbances in energy and glucose metabolism in estrogen-deficient animals better than BWS. Therefore, besides flavonoids in BWS, other components such as phytoalexins produced in MJ-BWS during MeJA-treatment might play a crucial role in the improvement., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Traditionally fermented soybeans (chungkookjang; TFC) may have potent anti-diabetic activity, depending on the ambient microorganisms and conditions. We hypothesized that one of the major Bacillus species in TFC contributes to the anti-diabetic activity and could be used to standardize a highly functional TFC. We tested the hypothesis by using cell-based studies to evaluate insulin sensitizing and insulinotropic action of chungkookjangs fermented with various Bacillus spp. and fermentation periods. The 70% methanol and water extracts of chungkookjang fermented with Bacillus licheniformis (BL) for 48 h contained similar profiles of isoflavonoids and peptides to methanol and water extracts of TFC with potent anti-diabetic activity. Water extracts (mainly containing peptides) of TFC and BL fermented for 48 h and 72 h had a better insulin sensitizing action via activating peroxisome proliferator-activated receptor-γ (PPAR-γ) and increased the expression of PPAR-γ in 3T3-L1 adipocytes better than unfermented cooked soybeans (CSB). The 70% methanol extracts (predominantly isoflavone aglycones) of BL fermented for 48 h and 72 h improved glucose-stimulated insulin secretion and protected β-cell viability better than CSB in insulinoma cells, and the improvement by BL was similar to TFC. In conclusion, the BL water extract fermented for 48 h exhibited equal insulin sensitization as TFC and BL methanol extract exerted similar insulinotropic actions to those of TFC. B. licheniformis may be one of the major microorganisms responsible for anti-diabetic actions of chungkookjang. It is important to make chungkookjang that retains the anti-diabetic properties of the most efficacious traditional chungkookjang using a standardized method.

Objective: Although soybeans have been shown to alleviate metabolic syndromes, fermented soybeans may have even greater effects. We investigated the antidiabetic effects of meju, a soy food that is fermented up to 2 mo, and the mechanism by which it exerts its effects., Methods: Meju was prepared by a traditional fermentation process: soybeans were fermented outdoors for 20 or 60 d. Methanol (M-60) and water (W-60) extracts from meju that had fermented for 60 d contained mostly isoflavonoid aglycones and small peptides, respectively, as opposed to mostly glycosylated isoflavonoids and proteins in the original soybeans., Results: Daidzein, M-60, and W-60 had better insulin-sensitizing actions by activating peroxisome proliferator-activated receptor-γ in 3T3-L1 adipocytes than did unfermented soybeans. In addition, Min6 insulinoma cells treated with genistein, M-60, and W-60 had greater glucose-stimulated insulin secretion capacity and greater β-cell viability than those treated with unfermented soybeans. This improvement was associated with insulin/insulin-like growth factor-1 signaling that was activated by the tyrosine phosphorylation of insulin receptor substrate-2 and serine phosphorylation of Akt, and this in turn increased pancreatic and duodenal homeobox-1 expression. Furthermore, genistein, daidzein, and M-60 stimulated glucagon-like peptide-1 secretion in enteroendocrine NCI-H716 cells, which generated insulinotropic actions., Conclusion: The compositional changes in isoflavonoids and peptides that occurred during a longer fermentation period, without the use of salt, enhanced the antidiabetic effect of soybeans., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Testosterone deficiency deteriorates glucose and lipid metabolism with reducing muscle mass. We investigated whether the consumption of water extracts of Gastrodia elata Blume rhizome (GEB) rich in gastrodin would reduce the symptoms of testosterone deficiency and improve blood flow in orchidectomized (ORX) rats. ORX rats were given high-fat diets supplemented with either 1% cellulose (ORX-control), 0.3% GEB (GEB-L), or 1% GEB (GEB-H) for 8 weeks. Sham-operated rats were fed the same diet as OVX-control rats (normal-control). ORX-control rats had reduced serum testosterone levels by one-fifth, compared to normal-control rats. ORX-control rats exhibited decreased lean body mass, attenuated blood flow, and impaired cholesterol metabolism and glucose control due to decreased insulin secretory response. GEB increased serum insulin levels dose-dependently and GEB-H mostly enhanced dyslipidemia in ORX rats. GEB completely normalized arterial thrombosis time and blood flow in ORX rats. Interestingly, ORX-control rats showed attenuated hepatic insulin signaling but greater AMPK and CREB activities, which reduced triglyceride accumulation, compared to normal-control. GEB-H improved hepatic insulin signaling but maintained the AMPK and CREB activities in ORX rats. In conclusions, GEB ameliorated the impairment of cholesterol and glucose metabolism and blood flow in ORX rats. GEB may be a potential preventive measure for reducing the risk of cardiovascular diseases associated with testosterone deficiency. [ABSTRACT FROM AUTHOR]

The effect of ethanol extracts of Citrus junos Tanaka (yuja) peel (YE) on glucose control in subjects with impaired fasting glucose was evaluated. In this double-blind, crossover, placebo-controlled study, the participants were randomly assigned to one of two groups, placebo control or YE intervention group. We determined fasting plasma glucose (FPG), postprandial glucose (PPG), and fasting plasma insulin (FPI) concentrations; homeostatic model assessment-insulin resistance (HOMA-IR); and safety before and after the 8-week supplementation with YE or placebo. After 8 weeks of intervention, the YE group showed significantly lower FPG levels, FPI, and HOMA-IR compared to the placebo group. PPG and c-peptide were slightly reduced in the YE groups. There was no significant difference between the groups in safety parameters. Thus, these results suggest that YE may be effective for controlling fasting blood glucose levels and may serve as a useful supplement in subjects with prediabetes. [ABSTRACT FROM AUTHOR]

Abstract: Ethnopharmacological relevance: Fructus Schisandrae, the fruit of Schisandra chinensis (Turcz.) Baillon, has been traditionally used as a hypoglycemic agent in Asia and its extracts have been shown to improve insulin-stimulated glucose uptake in cell-based assays in previous studies. Aim of the study: We set out to determine which fractions of Fructus Schisandrae improved peroxisome proliferator-activated receptor (PPAR)-γ activity and glucose-stimulated insulin secretion in cell-based experiments. The fractions that enhance glucose homeostasis were then tested for their hypoglycemic effects and mechanism was examined. Materials and methods: The fractions (FS-0, FS-20, FS-40, FS-60, FS-80, FS-100) were made by extracting Fructus Schisandrae with 70% ethanol followed by its fractionation with a XDA column with a different ratio of methanol and water. The insulin-stimulated glucose uptake and PPAR-γ agonistic actions of each fraction were investigated in 3T3-L1 adipocytes and glucose-stimulated insulin secretion was determined in Min6 cells. The fraction(s) that were efficacious (200mg/kg bw) were orally given to 90% pancreatectomized (Px) diabetic rats for 8 weeks to evaluate insulin sensitivity in euglycemic hyperinsulinemic clamp and insulin secretion at hyperglycemic clamp. Results: FS-60 contains schizandrin, gomisin A and angeloylgomisin H while FS-80 contains deoxyschizandrin, γ-schizandrin, and gomisin N. A PPAR-γ agonistic action was greater in the ascending order of the control, FS-80 and FS-60 in 3T3-L1 adipocytes. FS-60 increased the glucose disposal rates of Px rats as much as rosiglitazone during euglycemic hyperinsulinemic clamp while hepatic glucose output at hyperinsulinemic clamped states decreased in the descending order of the control, FS-80, FS-60 with potentiating insulin signaling. At hyperglycemic clamp only FS-60 potentiated first phase insulin secretion in diabetic animals; the second phase was not increased. Conclusions: FS-60, a lignan-rich fraction, improves glucose homeostasis by increasing glucose disposal rates and enhancing hepatic insulin sensitivity by working as a PPAR-γ agonist in type-2 diabetic rats. [Copyright &y& Elsevier]

Abstract: Red peppers and red pepper paste are reported to have anti-obesity, analgesic and anti-inflammatory effects in animals and humans due to the capsaicin in red pepper. We investigated whether consuming capsaicin and capsiate, a nonpungent capsaicin analogue, modifies glucose-stimulated insulin secretion, pancreatic β-cell survival and insulin sensitivity in 90% pancreatectomized (Px) diabetic rats, a moderate and non-obese type 2 diabetic animal model. Px diabetic rats were divided into 3 treatment groups: 1) capsaicin (Px-CPA), 2) capsiate (Px-CPI) or 3) dextrose (Px-CON) and provided high fat diets (40 energy % fat) containing assigned components (0.025% capsaicin, capsiate, or dextrose) for 8 weeks. Both capsaicin and capsiate reduced body weight gain, visceral fat accumulation, serum leptin levels and improved glucose tolerance without modulating energy intake in diabetic rats. In comparison to the control, both capsaicin and capsiate potentiated first and second and phase insulin secretion during hyperglycemic clamp. Both also increased β-cell mass by increasing proliferation and decreasing apoptosis of β-cells by potentiating insulin/IGF-1 signaling. However, only capsiate enhanced hepatic insulin sensitivity during euglycemic hyperinuslinemic clamp. Capsiate reduced hepatic glucose output and increased triglyceride accumulation in the hyperinsulinemic state and capsiate alone significantly increased glycogen storage. This was related to enhanced pAkt→PEPCK and pAMPK signaling. Capsaicin and capsiate reduced triglyceride storage through activating pAMPK. In conclusion, capsaicin and capsiate improve glucose homeostasis but they differently enhance insulin sensitivity in the liver, insulin secretion patterns, and islet morphometry in diabetic rats. Capsiate has better anti-diabetic actions than capsaicin. [Copyright &y& Elsevier]