• Food Science and Biotechnology
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• v.16 no.1
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• pp.55-61
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• 2007

The antioxidant activities of water, ethanol, methanol, and chloroform extracts of Ulmus davidiana were evaluated using various antioxidant assays: DPPH (1,1-diphenyl-2-pricrylhydrazyl) free radical scavenging; hydroxyl radical scavenging; lipid peroxidation scavenging; and reducing power assays. All extracts, except the chloroform extract, demonstrated strong antioxidant activity in all assays. The chloroform extract had the highest hydroxyl radical scavenging activity, and its activity was equivalent to $\alpha$-tocopherol at a concentration of 0.5 mg/mL. Additionally, the antidiabetic activity of their extracts was also evaluated using a rat intestinal $\alpha$-glucosidase inhibition assay. Among all extracts investigated, the methanol extract had the highest $\alpha$-glucosidase inhibitory activity, although its activity was less than acarbose at $0.5\;{\mu}g/mL$. This result suggested that U. davidiana extracts may have antidiabetic activity. Total phenolic compounds and flavonoids were also measured. Phenolic compounds such as tannic acid, p-coumatric acid, and kaempferol were detected by high-performance liquid chromatography (HPLC). These results suggest that U. davidiana extracts may be useful as a potential source of antioxidant and antidiabetic materials.

• Microbiology and Biotechnology Letters
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• v.40 no.3
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• pp.180-185
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• 2012

Type 2 Diabetes Mellitus, a chronic metabolic disorder which results from a high blood glucose level, is one of the most prevalent and costly diseases of our time. Considering increasing rates of obesity and the aging population in Korea, the number of diabetic patients is likely to rise rapidly in the future. There are five conventional diabetic drugs which work through different mechanisms; sulfonylureas, biguanide, meglitinide, alpha-glucosidase inhibitors, and thiazolidinedione. Although they all have antidiabetic effects, some side effects such as hypoglycemia, weight gain and gastrointestinal intolerance are associated with them. Incretin based therapies, utilizing glucagon-like peptide-1 (GLP-1) and dipeptidyl peptidase-4 (DPP-4) inhibitors, which have a lower risk of adverse side effects, have recently been introduced. At present PPAR-targeting drugs are being actively developed. In this research review, particular emphasis has been placed on the current trends and possible biological targets for the new generation of antidiabetic drugs.

• YAKHAK HOEJI
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• v.47 no.1
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• pp.52-55
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• 2003

Antidiabetic activities of white ginseng 50％ ethanol extract (WGE) and IH901, an intestinal metabolite of ginsenoside R $b_1$, were compared in multiple low dose streptozotocin (STZ)-induced diabetic rats. WGE or IH901 were coadministered with STZ on Day 1 at dose of 100 and 300 mg or 10 and 30 mg, respectively, and continually administered for 16 days. STZ dissolved in citrate boner was injected intraperitoneally at dose of 20 mg/kg for 5 consecutive days. During the experiment, plasma glucose level and body weight were measured every 4$^{th}$ day. Amount of food and water intake were evaluated once a week and compared between groups. WGE and IH901 both significantly reduced the plasma glucose levels on Day 16 as compared with those of the diabetic control group. In the meantime, amount of food and water intake in WGE-and IH901-treated groups were significantly improved in a dose dependent fashion as compared with those of the diabetic control group. Taken together WGE and IH901 showed the comparable antidiabetic activities at the corresponding doses used in this experiment.

• Journal of the Korean Wood Science and Technology
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• v.47 no.4
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• pp.498-508
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• 2019

This study was carried out to investigate the potential of Korean red pine (Pinus densiflora) inner bark extracts as an antidiabetic agent. The ethyl acetate soluble fraction of the bark extracts was chromatographed on a Sephadex LH-20 column to yield five compounds, which structures were elucidated by NMR spectroscopy. The isolated compounds were (+)-catehin, (-)-epicatechin, taxifolin, taxifolin-3'-O-${\beta}$-D-(+)-glucose and $\tilde{n}$-courmaric acid. The antidiabetic activity of the different fractions, including the crude extracts and isolated compounds, was evaluated by ${\beta}$-cells insulin secretion and glucose uptake in skeletal muscle cells. The insulin secretion was 128% for taxifolin at $25{\mu}g/mL$. However, the other samples had no effect on this test. For the glucose uptake activity assay, $1{\mu}M$ insulin and 2 mM metformin were used as controls. Both the crude extract and taxifolin showed relatively low activity values, but the other samples yielded glucose uptake values over 260%. ${\rho}$-courmaric acid showed the highest uptake (270%). The results confirmed that Korean red pine extracts may be used as a hypoglycemic agent.

• Journal of Microbiology and Biotechnology
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• v.29 no.5
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• pp.713-720
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• 2019

Acanthamoeba castellanii belonging to the T4 genotype may cause a fatal brain infection known as granulomatous amoebic encephalitis, and the vision-threatening eye infection Acanthamoeba keratitis. The aim of this study was to evaluate the antiamoebic effects of three clinically available antidiabetic drugs, Glimepiride, Vildagliptin and Repaglinide, against A. castellanii belonging to the T4 genotype. Furthermore, we attempted to conjugate these drugs with silver nanoparticles (AgNPs) to enhance their antiamoebic effects. Amoebicidal, encystation, excystation, and host cell cytotoxicity assays were performed to unravel any antiacanthamoebic effects. Vildagliptin conjugated silver nanoparticles (Vgt-AgNPs) characterized by spectroscopic techniques and atomic force microscopy were synthesized. All three drugs showed antiamoebic effects against A. castellanii and significantly blocked the encystation. These drugs also showed significant cysticidal effects and reduced host cell cytotoxicity caused by A. castellanii. Moreover, Vildagliptin-coated silver nanoparticles were successfully synthesized and are shown to enhance its antiacanthamoebic potency at significantly reduced concentration. The repurposed application of the tested antidiabetic drugs and their nanoparticles against free-living amoeba such as Acanthamoeba castellanii described here is a novel outcome that holds tremendous potential for future applications against devastating infection.

• Journal of the Korean Society of Food Culture
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• v.36 no.5
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• pp.522-529
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• 2021

This study was conducted to analyze the antioxidant and antidiabetic activities of acorns according to the types of Quercus serrata Thunb (QST) and Q. acutissima Carruther (QAC). The total polyphenol contents of the extracts from QST and QAC were 220.59 and 320.96 mg GAE/g, respectively. The content of total polyphenol of QAC was higher than that of QAC (p<0.001). DPPH (2,2 Diphenyl 1 picrylhydrazyl) radical scavenging activity, reducing power and superoxide dismutase (SOD)-like activity were increased in a concentration-dependent manner by both acorn extracts, and QAC showed high activity in all antioxidant experiments (p<0.05). The inhibitory activities of α-glucosidase and α-amylase were also increased in a concentration-dependent manner, and QAC showed higher inhibitory activity than QST (p<0.05). Our study indicates that QST and QAC are functional food materials with high antioxidant and antidiabetic activities. In addition, QAC has a higher physiological activity than QST.

• The Korea Journal of Herbology
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• v.24 no.1
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• pp.159-167
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• 2009

Objectives : So-Dang-Hwan (SDH) is used as a traditional treatment of diabetes in oriental clinics in Korea. This study aimed to evaluate antidiabetic effect of SDH in streptozotocin (STZ)-induced diabetic rats. Methods : Diabetes was induced by i.p. injection of STZ (45 mg/kg) to Sprague-Dawley rats. Experimental animals (eight per group), were treated by oral administration of SDH (60 mg/kg body weight) and glibenclimide (1 mg/kg), a known antidiabetic drug for comparison, during 5 weeks. To veridy the effect of SDH, the levels of glucose, triglyceride, insulin, BUN and creatinine were measured in sera from experimental diabetic rats, and an oral glucose tolerance test (OGTT) was also performed. Results : SDH prevented body weight loss in diabetic rats. SDH exhibited at termination, a significant reduction in blood glucose levels in STZ-induced diabetic rats. SDH significantly reduced serum creatinine levels toward the normal levels. The OGTT results showed a significant improvement in glucose tolerance in rats treated with SDH. Conclusions : These data indicate that SDH treatment may improve glocose homeostasis in STZ-induced diabetes.

• Journal of Life Science
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• v.27 no.5
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• pp.579-583
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• 2017

Tetragonia tetragonioides seems to be a promising antiulcer medicinal plant due to the presence of water-soluble polysaccharide and cerebroside as its major constituents. There have been no previous studies using T. tetragonioides polysaccharide extract (TPE) to assess its antidiabetic effect in streptozotocin (STZ)-induced diabetes in mice. This study was designed to evaluate the antidiabetic effect of TPE in diabetic mice, which was established by one-week intraperitoneal injection of 65 mg/kg STZ. After three weeks of TPE treatment at a dose of 100 mg/kg, a maintenance of body weight, a decrement in plasma glucose, and low levels of triglyceride, lactate dehydrogenase, alkaline phosphatase, and glutamic pyruvic transaminase were observed in diabetic mice. Furthermore, the ingestion of TPE lowered the blood glucose levels during the oral glucose tolerance test (OGTT) and restored most of the tested parameters to their normal levels. Therefore, the antidiabetic potential of T. tetragonioides has been demonstrated for the first time by our research.

• Korean Journal of Clinical Pharmacy
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• v.29 no.3
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• pp.186-192
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• 2019

Background: Diabetes is associated with cancer risk in the aging population. Observational studies have indicated the beneficial effects of metformin against breast cancer, making studies on the anticancer potential of antidiabetic drugs worthwhile. This study investigated cancer incidence in patients on antidiabetic monotherapy. Methods: Using National Health Insurance Service data (2002-2013), a retrospective cohort study that included type 2 diabetes mellitus (T2DM) patients was conducted. Study subjects were enrolled if they were ${\geq}30$ years old, on monotherapy for diabetes, and cancer-free. They were followed up for cancer occurrence or death, until December 31st, 2013. A Cox proportional hazard model analysis was conducted between metformin and sulfonylurea (including meglitinide) users, to determine cancer risk, with adjustment for age, gender, comorbidity index, dyslipidemia, hypertension, and T2DM duration. Results: The number of antidiabetic monotherapy-treated T2DM patients without a history of cancer was 9,554 (metformin, n = 5,825; sulfonylurea, n = 3,225; others, n = 504). During the follow-up period (mean, 2.04; IQR, 3.18 years), the cancer incidence rate was 5.48/100 and 5.45/100 patient-years for metformin and sulfonylurea, respectively. The hazard ratio (HR) for risk of cancer incidence in the metformin group was 0.74 (95% confidence interval [CI], 0.66-0.83; p < 0.0001), compared with sulfonylurea. Additionally, the HRs for risks of lung, liver, and stomach cancer were respectively 0.46 (95% CI, 0.31-0.66; p < 0.0001), 0.41 (95% CI, 0.31-0.54; p < 0.0001), and 0.51 (95% CI, 0.35-0.73; p = 0.0003). Conclusion: Antidiabetic therapy with metformin reduces cancer risk by 26%, specifically for lung, liver, and stomach cancer.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.117-117
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• 2003

PPARs (peroxisome proliferator activated receptors) are member of nuclear hormone receptors superfamily. Activations of PPARs upon binding with ligands modulate glucose metabolite, differentiation of adipocyte, inflammation response, and so on. Thiazolidinedione analog is one of potential antidiabetic drug that binds and activates PPARν selectively and enhances insulin sensitivity. In an effort to develop novel and effective antidiabetic thiazolidindione analogs, syntheses of benzoxazole and benzothiazole-linked thiazolidinedione analogs were performed via coupling reaction of benzoxazolylalkylaminoethanol with hydroxybenzylthiazolidinedione to develop novel and effective antidiabetic thiazolidindiones. All compounds were evaluated their biological potency by PPARν transactivation assay and revealed the similar potency with Troglitazone. However, lengthening of N-alkyl substituent did not seem to be beneficial for the activity.