• Preventive Nutrition and Food Science
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• v.20 no.2
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• pp.94-101
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• 2015

Grape products have been known to exert greater antioxidant and anti-obesity than anti-hyperglycemic effects in animals and humans. Omija is used as an ingredient in traditional medicine, and it is known to have an anti-hyperglycemic effect. We investigated whether the combined extracts of grape pomace and omija fruit (GE+OE) could reduce fat accumulation in adipose and hepatic tissues and provide beneficial effects against hyperglycemia and insulin resistance in type 2 diabetic mice. C57BL/KsJ-db/db mice were fed either a normal control diet or GE+OE (0.5% grape pomace extract and 0.05% omija fruit extract, w/w) for 7 weeks. GE+OE decreased plasma leptin and resistin levels while increasing adiponectin levels and reducing the total white adipose tissue weight. Furthermore, GE+OE lowered plasma free fatty acid (FFA), triglyceride, and total-cholesterol levels as well as hepatic FFA and cholesterol levels. Hepatic fatty acid synthase and glucose 6-phosphate dehydrogenase activities were decreased in the GE+OE group, whereas hepatic ${\beta}$-oxidation activity was increased. Furthermore, GE+OE supplementation not only reduced hyperglycemia and pancreatic ${\beta}$-cell failure but also lowered blood glycosylated hemoglobin and plasma insulin levels. The homeostasis model assessment of insulin resistance levels was also decreased and the decrease seems to be mediated by the lowered activities of hepatic glucose-6-phosphatase and phosphoenolpyruvate carboxykinases. The present data suggest that GE+OE may have the potential to reduce hyperglycemia, insulin resistance, and obesity in patients with type 2 diabetes.

• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.280-285
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• 2003

Hypoglycemic and hypolipidemic efficacies of cultured ginseng (CG) in streptozotocin (STZ)-induced diabetic rats were investigated. Male Sprague-Dawley rats were divided into normal and three diabetic groups. The diabetic groups were fed CG-free control diets supplemented with 5 and 10% of CG for 2 weeks. CG-supplemented groups showed significantly lower blood glucose, triglyceride, and total cholesterol content compared to the diabetic control group. CG supplementation at 5% significantly increased plasma high density lipoprotein (HDL)-cholesterol content compared to the diabetic control group. CG significantly increased plasma HDL-cholesterol/total cholesterol ratio and reduced atherogenic index, whereas, it did not affect plasma total lipid content in diabetic rats. The 5% CG reduced plasma AST and ALT activities in diabetic rats and inhibited the reduction of plasma creatinine level caused by STZ-treatment in rats. These data suggest that tissue-cultured ginseng has hypoglycemic, hypolipidemic, and anti-atherogenic effects on STZ-diabetic rats and can be useful as a dietary supplement for the treatment of diabetes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1785-1792
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• 2015

This study was carried out to investigate the antidiabetic, alcohol metabolism, anti-inflammatory, and hepatoprotective effects of Acer tegmentosum extracts (ATE). A. tegmentosum has been traditionally used as a folk medicine to treat hepatic disorders. The antioxidative activities of ATE were measured by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and superoxide (SOD) assay. DPPH radical scavenging and SOD activities of ATE were about 89% and 82.9% at $0.5{\mu}g/mL$, respectively. Alcohol dehydrogenase and acetaldehyde dehydrogenase activities were 118.0% and 177% at 2 mg/mL, respectively. ${\alpha}-Glucosidase$ inhibitory activity of ATE was 75% higher at $50{\mu}g/mL$ and remarkably increased in a dose-dependent manner. Nitric oxide productions in macrophage RAW 264.7 cells stimulated by lipopolysaccharide was reduced to 16.7% by addition of ATE at 1 mg/mL. ATE showed significant protective effects against tacrine-induced cytotoxicity in Hep G2 cells at $100{\mu}g/mL$. Based on our results, we conclude that ATE may be used as a major pharmacological agent and anti-diabetic, anti-hepatitis, and anti-inflammatory remedy.

• Biomolecules & Therapeutics
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• v.12 no.4
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• pp.215-220
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• 2004

In an attempt to develop new anti-diabetic agents, a series of aryloxypropanolamine derivatives was synthesized to serve as ${\beta}_3$ adrenoceptor agonists. Among these derivatives, 1-{1-methyl-3-[4-(2-methyl-2H-1,2,3,4-tetrazol-5-yl)phenyl]propylamino}-3-phenoxy-2-propanol (KR60886) possessed a high affinity for the ${\beta}_3$ adrenoceptor (Ki = 28 nM) and moderate affinities for ${\beta}_1$ and ${\beta}_2$ adrenoceptors (Ki = 95 nM and 100 nM, respectively). In addition, KR60886 stimulated cAMP production with an EC$_{50}$ of 0.4 ${\mu}M$, confirming its agonistic activity for the ${\beta}_3$ adrenoceptor. In vivo activities of KR60886 were examined by using a fat-fed/streptozotocin (STZ)-treated rat model and the ob/ob mouse model. Oral administration of KR60886 (10 mg/kg) for 3 days (b.i.d.) to fat-fed/STZ-treated rats significantly lowered plasma glucose levels and reduced plasma free fatty acid concentrations. Similarly, KR60886 treatment (10 mg/kg/day for 7 d) resulted in a reduction of plasma glucose concentrations in ob/ob mice. The present study suggests that KR60886 is a potent ${\beta}_3$ receptor agonist with in vivo anti-diabetic properties.

• KSBB Journal
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• v.27 no.6
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• pp.361-366
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• 2012

We investigated the anti-diabetic activity and enzymatic activity of 24 commercial doenjang samples certified for traditional foods. Twenty four doenjang samples showed the wide ranges in enzymatic activities (protease activities 0-50.45 unit/g, ${\alpha}$-amylase activities 0-675.9 unit/g, ${\beta}$-amylase 13.6-308.6 unit/g), and there were no difference in enzymatic activity by the producing region. To evaluate the potential anti-diabetic activity of 24 doenjang samples, we examined the effect of doenjang methanol extract (DME) on 2-[n-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amyno]-2-deoxy-d-glucose (2-NBDG) uptake. Ten samples among 24 samples significantly stimulated the uptake of 2-NBDG. When the cells were treated with DME at 400 ug/mL, No. 17 and 23 specially stimulated 2-NBDG uptake by 1.23-fold and 1.25-fold, respectively, compared with untreated control cell. And there were no cytotoxicity in the C2C12 cells treated with DME at concentration of 500 ug/mL. Among 24 samples, No. 6, 7, 12, 21 and 24 showed the ${\alpha}$-glucosidase inhibitor activity at concentration of 10 mg/mL; however, they were less effective than acarbose which is a commercial ${\alpha}$-glucosidase inhibitor.

• Journal of Life Science
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• v.26 no.8
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• pp.921-927
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• 2016

Postprandial hyperglycemia is an early defect of type 2 diabetes and one of primary anti-diabetic targets. The alpha-glucosidase inhibitors regulate postprandial hyperglycemia by impeding the rate of carbohydrate (such as starch) digestion in the small intestine. This study was designed to investigate the inhibitory actions of mulberry fruit extract (MFE) on α-glucosidase and α-amylase activities, and its alleviating effect on postprandial hyperglycemia activities in vitro and in vivo. Male four-week old ICR mice and streptozotocin (STZ)-induced diabetic mice were treated with mulberry fruit extract. MFE showed strong inhibitory effects against α-glucosidase and α-amylase activities, with half-maximal inhibitory concentration (IC₅₀) values of 0.16 and 0.14 mg/ml, respectively, and was more effective than acarbose, which was used as a positive control. The increase in postprandial blood glucose levels was more significantly attenuated in the MFE-administered group mice than in the control group mice of both STZ-induced diabetic and normal mice. Moreover, the area under the glucose response curve significantly decreased following MFE administration in diabetic mice. These results indicate that MFE may be a potent inhibitor of α-glucosidase and α-amylase, and helpful in suppressing postprandial hyperglycemia in diabetic mice. The mulberry fruit extracts may be considered as a potential candidate for the management of diabetes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1414-1418
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• 2017

Inhibition of advanced glycation end product (AGE) formation is a valuable therapeutic strategy for the regulation of diabetic complications. This study was conducted to identify potential therapeutic targets of anti-diabetic complications from irradiated mangiferin using AGE formation assay. Radiolytic degradation of the xanthone glucoside mangiferin by gamma-irradiation resulted in three degraded mangiferin analogues: mangiferdiol (1), mangiferinol (2), and isomangiferinol (3). Structures of the three newly generated compounds were characterized by interpretation of nuclear magnetic resonance ($^1H$, $^{13}C$ NMR, $^1H-^1H$ COSY, HSQC, HMBC, and NOESY) and mass spectroscopic data. The anti-diabetic complication of the generated mangiferin derivatives were tested using in vitro AGE formation method. Among the tested degraded products, mangiferinol (2) and isomangiferinol (3) exhibited significantly improved potency against AGE formation inhibitory activities with $IC_{50}$ values of $5.6{\pm}0.8$ and $7.6{\pm}0.9{\mu}M$, respectively. This result implies that xanthone derivatives generated from gamma-irradiated mangiferin might be beneficial for prevention of diabetic complication and related diseases.

• Korean Journal of Pharmacognosy
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• v.25 no.1
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• pp.51-58
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• 1994

The studies were conducted to investigate the anti-diabetic activities on the hyperglycemia induced by streptozotocin in rats, anti-hypertensive activities in SHR, anti-fatigue and decrease of body weight activities in mice by Kyung Ok-Ko water extract and drink, which is a traditional preparation in Korea. 1. The blood glucose levels of streptozotocin-induced hyperglycemic rats were dose-dependently decreased by administrations of various doses(300, 600, 1200 mg/kg) of Kyung Ok-Ko water extract. Particularly, administration of 600, 1200 mg/kg were significantly shown to decrease glucose levels comparing with control group. 2. The serum total cholesterol levels of streptozotocin-induced hyperglycemic rats were dose-dependently decreased by administrations of various doses(300, 600, 1200 mg/kg) of Kyung Ok-Ko water extract. Particularly, administration of 600, 1200 mg/kg were significantly shown to decrease total cholesterol levels comparing with control group. 3. The serum triglyceride levels of streptozotocin-induced hyperglycemic rats were dose-dependently decreased by administrations of various doses(300, 600, 1200 mg/kg) of Kyung Ok-Ko water extract. Particularly, administration of 600, 1200 mg/kg were significantly shown to decrease triglyceride levels comparing with control group. 4. The blood pressure in SHRs were dose-dependently lower descended by administration of Kyung Ok-Ko water extract 300, 600, and 1200 mg/kg, respectively. 5. The swimming time of Kyung Ok-Ko water extract(100, 200, 400 mg/kg) and drink(0.7, 1.4, 2.1 ml/kg) were significantly extended to all experimental group dose-dependantly. 6. The decrease of body weight of Kyung Ok-Ko water extract(100, 200, 400 mg/kg) and drink(0.7, 1.4, 2.1 ml/kg) were significantly evaluated dose-dependently in all experimental group.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.96-96
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• 2019

Sedum kamchaticum, Sedum middendorffianum and Sedum takesimense belong to the sebum species. Especially, Sedum takesimense is a Korean native species growing only on Ullenung-do. Few studies for the biological activities of these plants have been reported. In this study, we examined biological activity and the contents of functional components of the aerial part and the root part of Sedum kamchaticum, Sedum middendorffianum and Sedum takesimense. As the results, the roots of Sedum takesimense showed the highest total phenolic contents (TPC : $13040{\pm}50.0mg\;GAE{\cdot}100g^{-1}$), and the aerial part of Sedum takesimens showed the highest total flavonoid contents (TFC : $2722.2{\pm}107.1mg\;CAE{\cdot}100g^{-1}$). Meanwhile, Sedum middendorffianum exhibited the highest anti-oxidant activity (DPPH $RC_{50}$ value of aerial part : $50.69{\pm}0.75{\mu}g{\cdot}mL^{-1}$, DPPH $RC_{50}$ value of root part : $27.27{\pm}0.55{\mu}g{\cdot}mL^{-1}$; ABTS $RC_{50}$ value of aerial part : $11.32{\pm}0.38{\mu}g{\cdot}mL^{-1}$, ABTS $RC_{50}$ value of roots part $5.54{\pm}0.02{\mu}g{\cdot}mL^{-1}$). The root part of Sedum middendorffianum showed the potent alpha glucosidase inhibitory activity (AGI $IC_{50}$ : $60.69{\pm}0.72{\mu}g{\cdot}mL^{-1}$). In order to elucidate active principle of Sedum middendorffianum that was shown the most potent antioxidant and anti-diabetic activities, the methanol extract of Sedum middendorffianum was fractionated with various solvents according to the polarity successively. As a result, EtOAc fraction of Sedum middendorffianum showed the highest contents of functional components (TPC : $16245.8{\pm}1025.7mg\;GAE{\cdot}100g^{-1}$, TFC : $4850.4{\pm}182.9mg\;CAE{\cdot}100g^{-1}$). And it also showed excellent anti-oxidant activities (DPPH $RC_{50}$ : $14.0{\pm}0.6{\mu}g{\cdot}mL^{-1}$, ABTS $RC_{50}$ : $3.4{\pm}0.1{\mu}g{\cdot}mL^{-1}$) and anti-diabetic activity (AGI $IC_{50}$ : $79.0{\pm}2.2{\mu}g{\cdot}mL^{-1}$). Above results suggest that Sedum middendorffianum can be developed to health functional material as a plant resource with potent antioxidant activity.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.1
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• pp.101-108
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• 2014

This study was conducted in order to compare the biological activities of water extracts and sugar immersion extracts of green pepper (Capsicum annuum L.), purslane (Portulaca oleracea L.) and shiitake (Lentinula edodes (Berk.) Pegler) by measuring total polyphenol and flavonoid contents, antioxidant activities and inhibitory effects on ${\alpha}$-amylase and ${\alpha}$-glucosidase. The contents of total polyphenols and flavonoids were higher in water extracts than in sugar immersion extracts. The anti-oxidative activities of water and sugar immersion extracts were measured using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity assay and reducing power assay. All extracts scavenged radicals in a concentration-dependent manner, and water extracts showed stronger radical scavenging activity and reducing power than sugar immersion extract. However, they all exhibited lower activities than ascorbic acid. Compared to the anti-diabetic drug acarbose, which was used as a positive control, the two types of extracts exhibited low ${\alpha}$-glucosidase inhibitory activities, although the activity of sugar immersion extracts were 2-fold higher than that of water extracts. ${\alpha}$-Amylase inhibitory action was not observed for any of the extracts. Finally, by cytotoxicity test, we confirmed that sugar immersion extracts were safer than water extracts. These results indicate that water extracts and sugar immersion extracts of green pepper, purslane and shiitake have different advantages in terms of their antioxidant and anti-diabetic effects, respectively.