• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.701-707
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• 2007

Anti-diabetic effect of Platycodi radix (PR) extract fractions was determined if vitro by investigating insulin-like action, insulin sensitizing action, glucose-stimulated insulin secretion, gene expression related to ${\beta}-cell$ function and mass, and ${\alpha}$-glucoamylase suppressing action. Insulin-like activity was not promoted by the treatment of PR methanol factions in 373-L1 fibroblast. However, treatment with 0, 20 and 100% PR methanol fractions along with 1 ng/mL insulin increased insulin-stimulated glucose uptake in 373-L1 adipocytes. In addition, the treatment of 0% and 100% methanol fractions along with differentiation inducers significantly increased the differentiation of 373-L1 fibroblasts to adipocytes. These fractions may contain insulin sensitizer. The 20%, 80% and 100% methanol fractions enhanced glucose-stimulated insulin secretion in Min6 cells, insulin secreting cell line. This was related to the mechanism to promote glucose sensing and ${\beta}-cell$ proliferation, which was regulated by the induction of IRS-2, glucokinase and PDX-1 genes. As expected, 20, 80 and 100% methanol fractions increased mRNA levels of IRS-2, glucokinase and PDX-1 genes. However, PR fractions did not affect the ${\alpha}-glucoamylase$ activity in vitro. These data suggested that PR extract fractions have anti-diabetic actions through improving insulin sensitization, glucose-stimulated insulin secretion, and ${\beta}-cell$ proliferation. Therefore, PR extracts can be beneficial for anti-diabetic treatment in lean diabetic patients.

• The Journal of Dong Guk Oriental Medicine
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• v.7 no.1
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• pp.75-86
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• 1998

Studies were conducted on anti-dibetic effect of the water extract from leaves of Eriobotryae folium, which had been used in Korea as a remedy for dibetes. The extract was found to inhibit the increase in the plasma level of sugar bu the not the decrease in the plasma level of insulin in alloxan-induced dibetic rats. Also, we investigated the in vivo effect of an aqueous extract (referred to as EF) from Eriobotryae folium on glucokinase and hexokinase activities of diabetes mellitus induced by interleukin-$1{\beta}$ ($IL-1{\beta}$). After 1 week of $IL-1{\beta}$ injection, the levels of serum glucose concentration and insulin secretion were dramatically increased. However, the insulin secretion was decreased with administration of EF. The level of glucose concentration was decreased by EF administration. Furthermore, it was observed that EF was effective in recovering the levels of insulin secretion. Enzyme activities of the glucokinase and hexokinase, which are key enzymes of glucose phosphorylastion, were decreased by $IL-1{\beta}$. EF administration to the mice allowed proportional increasing by stimulation of induction of enzyme activities as high as normal group. These results suggested that EF is highly effective in treatment of diabetes mellitus induce by $IL-1{\beta}$.

• Journal of Genetic Medicine
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• v.18 no.2
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• pp.132-136
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• 2021

Maturity-onset diabetes of the young (MODY) is caused by autosomal dominant pathogenic variants in one of 14 currently known monogenic genes. Characteristics of patients with MODY include early-onset clinical disease with a family history of diabetes and negative autoantibodies and may present with heterogeneous phenotypes according to the different subtypes. Here, we report a patient with early-onset diabetes who presented asymptomatic mild fasting hyperglycemia with the absence of autoantibodies. She was diagnosed with glucokinase (GCK)-MODY caused by a GCK variant, c.1289T>C (p.L430P), identified by targeted gene-panel testing, and the affected father had the same variant. We interpreted this rare missense variant as a likely pathogenic variant and then she stopped taking oral medication. This case highlights the usefulness of gene-panel testing for accurate diagnosis and appropriate management of MODY. We also note the importance of familial genetic testing and genetic counseling for the proper interpretation of MODY variants.

• The Journal of Internal Korean Medicine
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• v.25 no.2
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• pp.288-297
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• 2004

Objective : This study was undertaken to investigate how Bombycis corpus (BC) effects the development and progress of complications occurring in Diabetes Mellitus (DM). Methods : Laboratory rats were seperated into three groups; normal, rats with DM and treated with BC, and rats with DM and not treated. In this study DM was experimentally induced through injection of streptozotocin. The BC treated group was given BC extract p.o. for 15 days. Then, The activities of glucose phosphatic enzymes and polyol pathway channels were observed. Results : The blood glucose level greatly increased in the DM groups after injection of streptoztocin, but it significantly decreased in the BC treated group. Significantly enhanced levels of serum insulin levels were seen in the BC treated group, while supressed levels were seen in the untreated DM group. Weight was recovered by the BC treated group, matching the normal group. Decreased enzyme activity of aldose reductase, sorbitol dehydrogenase and glucose-6-phosphatase were seen in BC treated diabetic rats. Increased enzyme activity, of the glucokinase and hexokinase were seen in BC treated diabetic rats. Conclusions : This study suggests that BC normalized the blood glucose and serum insulin levels destablized by DM. Because increased activity of glucose phosphatic enzymes, glucokinase and hexokinase, and decreased glucose-6-phosphatase activity, and suppression of polyol pathway enzymes, aldose reductase and sorbitol dehydrogenase, were all seen, these observations suggest that BC suppresses blood glucose levels and prevents complications due to DM.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1311-1315
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• 2006

Aminocyclitol antibiotic validamycin A, a prime control agent for sheath blight disease of rice plants, is biosynthesized by Streptomyces hygroscopicus var. limoneus. Within the validamycin biosynthetic gene cluster, vldBC forms an operon of vldABC with vidA, the gene encoding 2-epi-5-epi-valiolone synthase. Biochemical studies, employing the recombinant proteins from Escherichia coli, established VldB and VldC as D-glucose $\alpha$-1-phosphate uridylyltransferase and glucokinase, respectively. This finding substantiates that the validamycin biosynthetic gene cluster harbors genes encoding the enzymes for UDP-glucose formation from glucose. Therefore, we propose that validamycin biosynthesis employs its own catalysts to generate UDP-glucose, but not depending on the primary metabolism.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.682-687
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• 2020

This study was performed to investigate the antidiabetic effect of ethanol extract of Phelladrindron Amurense Rupr (P.A) in Streptozotocin(STZ) induced diabetic rats. Diabetes was induced by intravenous injection of STZ at a dose of 45mg/kg,b.w. dissolved in citrate buffer. The ethanol extract of P. A was orally administrated once a day for 7 days at a dose of 1,000mg/kg. The content of serum glucose, was significantly decreased in P.A treated group compared to the those of STZ-control group. The content of hepatic glycogen and activities of glucokinase(GK) and glucose-6-phosphate dehydrogenase(G-6-PDH) were significantly increased(p<0.05), and activity of glucose-6-phoshatase(G-6-Pase) was significantly decreased(p<0.05) in P.A treated group compared to those of STZ-control group, These results indicated that ethanol extract of P.A have antidiabetic effect in STZ-induced diabetic rats.

• The Korean Journal of Food And Nutrition
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• v.23 no.2
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• pp.233-239
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• 2010

Phenolic acid concentrates of rice bran(RB-ex) and hydroxycinnamic acids were investigated for their anti-hyperglycemic activities through glucose uptake and glucokinase activity using HepG2 cells and stimulatory effects on insulin secretion using HIT-T15 cells. RB-ex was prepared as an ethylacetate extract after alkaline hydrolysis and hydroxycinnamic acids, found as major compositions of RB-ex, such as ferulic acid(FA), sinapic acid(SA) and p-coumaric acid(p-CA) were investigated to compare with the properties of RB-ex. The properties of glucose uptake in HepG2 cells were examined in the absence of insulin and two different glucose concentrations(5.5 mM and 25 mM). RB-ex and FA showed anti-hyperglycemic activities through the increase of glucose uptake and the stimulation of glucokinase activity in HepG2 cells. RB-ex exhibited higher glucose uptakes with higher glucose concentrations, whereas FA exhibited the same increasing effects on both concentrations of glucose. RB-ex and FA exhibited doubled glucokinase activities relative to control. In the presence of insulin in the 25 mM glucose-containing medium, the levels of glucose uptake were increased in all treatments compared with control. As stimulatory effects of samples on insulin secretion were estimated, RB-ex and FA stimulated insulin secretion at a concentration of 25 ${\mu}g/m{\ell}$ and in particular, FA showed the highest amount of insulin-release in HIT-T15 cells. Antioxidative effects on HIT-T15 cells, RB-ex and hydroxycinnamic acids, excluding p-CA, showed inhibitory activities of 78% to 80% at a concentration of 100 ${\mu}g/m{\ell}$. On the basis of these results, we conclude that RB-ex and FA could help decrease blood glucose levels and prevent the cell damages via antioxidant activity.

• Journal of Ginseng Research
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• v.22 no.1
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• pp.51-59
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• 1998

In this study, rat hepatocytes known to have active glucose metabolism were obtained to investigate the hypoglycemic action of fat soluble fraction of red ginseng by using the liver perfusion technique and incubated in two different media-one containing insulin and glucagon (control group), and the other containing glucagon only The activities of main regulating enzymes, such as glucokinase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenate, and glucose 6-phosphatase, related to metabolic pathways of glucose in these two kinds of hepatocytes were compared between these two groups and the effects of addition of fat soluble fraction ($10^1$~$10^4$%) from red ginseng to these two groups on these enzymes were also detected. The results were as follows. The specific activity of enzymes such as glucokinase, flucorse 6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase related to glucose-consuming pathways of insulin-deficient group was much less than control one. However, their decreased activity was recovered after the addition of fat-soluble fraction at all range of concentrations. The specific activity of these enzymes after the addition of ginseng components to the control group was also increased. On the other hand, the specific activity of glucose 6-phosphatase related to glucose-producing pathway of insulin-deficient group was much higher than control one, but their increased activity was decreased obviously after the addition of fat soluble fraction at all range of concentrations. The same results were observed after the addition of fat-soluble fraction to the control group. These results suggest that the red ginseng saponin components might be effective on diabetic hyperglycemia by regulating the activity of enzymes related to glucose metabolism directly and/or indirectly. The effects of fat-soluble fraction ($10^2$%) and ginsenosides (mixture, $Rb_1$ and $Rg_1$, $10^4$%) on hypoglycemic action were compared. As a result, they showed considerable effect on hyperglycemia, but the best eff ect on the activities of glucokinase and glucose 6-phosphate dehydrogenase was appeared by ginsenoside $Rb_1$ and that of 6-phosphogluconate dehydrogenase and glucose 6-phosphatase was by ginsenoside mixture.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.5
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• pp.542-547
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• 2008

The anti-diabetic effects of water extracts (WE) from medicinal herbs on hepatic glucose-regulating enzymes, such as glucokinase (GCK), pyruvate dehydrogenase (PDH), acetyl-CoA carboxylase (ACC) and ${\alpha}$-glucosidase, were studied using the cytosol fraction in liver and mitochondia fraction in heart of a type II diabetic animal (GK rat, Goto-Kakizaki). The free radical scavenging activity of water extracts by DPPH method was also tested. We found that free radical scavenging activity was strong in Corni fructu (CF), Mokdan Bark (MDB), Chenhwabon (CHB) and Sanyack (SY), while that of Backbocreng (BBR), Shuckgihwang (SGH) and Taecsa (TS) was lower. For GCK activity in cytosol of liver, CF and CHB had a more effective activity than other extracts. PDH activity in mitochondria fraction of heart was higher in all of the extracts, expect for the TS extract, than in the control. ACC activity in cytosol fraction of liver was significantly higher in the CF, CHB, SGH, TS and SY extracts than in the control. CF, BBR and MDB led to a decrease in the ${\alpha}$-glucosidase activity. Therefore, these results suggest that all of the extracts may be used as functional material in the development as anti-diabetic functional food and medicine.

• Journal of Nutrition and Health
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• v.47 no.3
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• pp.167-175
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• 2014

Purpose: Previous studies have shown that treatment with Smilax china L. leaf extract (SCLE) produces antidiabetic effects due to ${\alpha}$-glucosidase inhibition. In this study, we examined the mechanism underlying these antidiabetic effects by examining glucose uptake in HepG2 cells cultured with SCLE. Methods: Glucose uptake and glucokinase activity were examined using an assay kit. Expression of glucose transporter (GLUT)-2, GLUT-4, and HNF-$1{\alpha}$ was measured by RT-PCR or western blot. Results: Treatment with SCLE resulted in enhanced glucose uptake in HepG2 cells, and this effect was especially pronounced when cells were cultured in an insulin-free medium. SCLE induced an increase in expression of GLUT-2 but not GLUT-4. The increase in the levels of HNF-$1{\alpha}$, a GLUT-2 transcription factor, in total protein extract and nuclear fraction suggest that the effects of SCLE may occur at the level of GLUT-2 transcription. In addition, by measuring the change in glucokinase activity following SCLE treatment, we confirmed that SCLE stimulates glucose utilization by direct activation of this enzyme. Conclusion: These results demonstrate that the potential antidiabetic activity of SCLE is due at least in part to stimulation of glucose uptake and an increase in glucokinase activity, and that SCLE-stimulated glucose uptake is mediated through enhancement of GLUT-2 expression by inducing expression of its transcription factor, HNF-$1{\alpha}$.