• Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.17-22
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• 2024

Diabetes Mellitus (DM) is a major health issue increasing worldwide. Currently, nearby half a billion people have diabetes. Two major types of DM that type 1 and type 2-DM have different etiologies but feature a crucial common pathological transition into dysfunction of pancreatic β-cells and consequently leading hyperglycemia and finally go into DM. Therefore, maintaining of β-cells such as preventing β-cells degeneration, and promoting β-cells regeneration and proliferation will be essential approaches in prevention and/or treatment of DM. There are many reports that various types of seaweed control metabolic diseases such as obesity, high blood pressure, and blood sugar control. However, no new drug candidates have been developed yet. Additionally, although seaweed has excellent blood sugar control effects, there is no evidence that it directly proliferates or regenerates beta cells. Therefore, we studied on the promotion of β-cell regeneration by a seaweed, Polysiponia morrowii extract (PME) which preserves β-cells and maintains its function. As a result, it was confirmed that PME directly promotes the proliferation of pancreatic islet β-cells with insulin secretion function in in vivo. Therefore, PME shows potential as a candidate for β-cell regeneration that may play a fundamental role in the treatment of diabetes.

• Biomolecules & Therapeutics
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• v.28 no.2
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• pp.163-171
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• 2020

Silibinin exhibits antidiabetic potential by preserving the mass and function of pancreatic β-cells through up-regulation of estrogen receptor-α (ERα) expression. However, the underlying protective mechanism of silibinin in pancreatic β-cells is still unclear. In the current study, we sought to determine whether ERα acts as the target of silibinin for the modulation of antioxidative response in pancreatic β-cells under high glucose and high fat conditions. Our in vivo study revealed that a 4-week oral administration of silibinin (100 mg/kg/day) decreased fasting blood glucose with a concurrent increase in levels of serum insulin in high-fat diet/streptozotocin-induced type 2 diabetic rats. Moreover, expression of ERα, NF-E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) in pancreatic β-cells in pancreatic islets was increased by silibinin treatment. Accordingly, silibinin (10 μM) elevated viability, insulin biosynthesis, and insulin secretion of high glucose/palmitate-treated INS-1 cells accompanied by increased expression of ERα, Nrf2, and HO-1 as well as decreased reactive oxygen species production in vitro. Treatment using an ERα antagonist (MPP) in INS-1 cells or silencing ERα expression in INS-1 and NIT-1 cells with siRNA abolished the protective effects of silibinin. Our study suggests that silibinin activates the Nrf2-antioxidative pathways in pancreatic β-cells through regulation of ERα expression.

• Journal of Digital Convergence
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• v.17 no.7
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• pp.275-284
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• 2019

Antidolary active and anti-sugar mechanisms of the ova family (石斛; Dendrobii herba) ethanol extract (EED) were investigated. The EED was administered orally four times a day in a diabetic mouse induced by strepto Joe Toshin to reveal and reveal its pharmacological miracle through experimental studies that reduce the liver function of empty blood sugar, glythamic oxal acetate levels, insulin levels and glutamic acid trans aminaase and glutamic acid pyruvic acid trans amine. EED increased insulin secretion by glucose in RINm5F beta cells as well as intraperitoneal glucose intakes in L6 muscle cells. Thus, EED has shown great promise in displaying anti-diabetes activity not only by increasing insulin secretion but also by increasing intakes per cell, and hopes that future research on pharmacological mechanisms for quartz (Dendrobii herba) ethanol extract will be more active and contribute greatly to the treatment of diabetes.

• The Korean Journal of Food And Nutrition
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• v.21 no.4
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• pp.425-429
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• 2008

Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. Type 1 diabetes, or juvenile-onset diabetes, results from a cellular-mediated autoimmune destruction of the ${\beta}$-cells of the pancreas. Type 2 diabetes, or adult-onset diabetes, is a term used for individuals who have insulin resistance, a condition that makes it harder for the cells to properly use insulin, and usually have relative insulin deficiency. The diabetes causes the onset of chronic complications and diabetic neuropathy is one of the most debilitating complications. In this study, the hypoglycemic effect and the preventive effect of diabetic complications of Dioscorea rhizoma extract(DRE) were examined in rodent model. We investigated the glucose tolerance test and long term hypoglycemic effect of DRE in Type 1 streptozotocin-induced diabetic rats and Type 2 diabetic db/db mice. DRE showed a hypoglycemic effect on blood glucose levels than that of control group in Type 1 streptozotocin-induced diabetic rats and Type 2 diabetic db/db mice. On the basis of our results, we conclude that long-term use of DRE might help decrease blood glucose level and prevention of diabetes-associated complication.

• Journal of Yeungnam Medical Science
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• v.18 no.1
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• pp.94-100
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• 2001

Background: It is doubtful that aging causes deteriorated glucose metabolism and insulin resistance of skeletal muscle. Some researchers had different results about it. So we have studied the mechanism responsible for the abnormal glucose tolerance associated with aging in rapidly growing and matured rats. Materials and Methods: Animals were used S.D. rats. Growing rats were 7 weeks old (BW: 160-190 gm) and matured rats were 28 weeks old (BW: 420-525 gm). Results: Fasting blood glucose and plasma insulin levels were significantly elevated in matured rat compared with growing rats. And during oral glucose tolerance test the glucose level was also significantly elevated in matured rats. These results confirmed an insulin resistant state of aging. Insulin levels at 30 minutes of oral glucose tolerance test was significantly elevated in growing rat. But at 120 minutes it was maintained at higher level in matured rats than in growing rats. It suggested the possibility of increased insulin secretion by initial stimulation of beta-cells in growing rats, and increased secretion and decreased catabolic rate of insulin in matured rats. Glucose uptake rate of soleus muscle in matured rats was lower than that of growing rats, but the difference was not statistically significant. The dose(insulin)-responsive(glucose uptake) curve of soleus muscle was only slightly deviated to the right side. Conclusion: Glucose metabolism of rat skeletal muscle was worsened by aging. The data of glucose uptake experiments suggested the possibility of insulin resistance of skeletal muscle in matured rats. but the mechanism of insulin resistance of skeletal muscle need further studies.

• BMB Reports
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• v.40 no.6
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• pp.1058-1068
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• 2007

The post-translational modifications of Ser and Thr residues by O-linked $\beta$-N-acetylglucosamine (O-GlcNAc), i.e., O-GlcNAcylation, is considered a key means of regulating signaling, in a manner analogous to protein phosphorylation. Furthermore, it has been suggested that the increased flux of glucose through the hexosamine biosynthetic pathway (HBP) stimulates O-GlcNAcylation, and that this may be responsible for many of the manifestations of type 2 diabetes mellitus. To determine whether excessive O-GlcNAcylation of target proteins results in pancreatic $\beta$ cell dysfunction, we increased nucleocytoplasmic protein O-GlcNAcylation levels in $\beta$ cells by exposing them to streptozotocin and/or glucosamine. Streptozotocin and glucosamine co-treatment increased O-GlcNAcylated proteomic patterns as assessed by immunoblotting, and these increases in nuclear and cytoplasmic protein O-GlcNAcylations were accompanied by impaired insulin secretion and enhanced apoptosis in pancreatic $\beta$ cells. This observed $\beta$cell dysfunction prompted us to examine Akt and Bcl-2 family member proteins to determine which proteins are O-GlcNAcylated under conditions of high HBP throughput, and how these proteins are associated with $\beta$ cell apoptosis. Eventually, we identified ten new O-GlcNAcylated proteins that were expressed during $\beta$ cell apoptosis, and analyzed the functional implications of these proteins in relation to pancreatic $\beta$ cell dysfunction.

• Journal of the Korean Applied Science and Technology
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• v.1 no.1
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• pp.37-47
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• 1984

Effects of garlic on hypocholesterolemia, anticoagulation and hypoglycemia were studied in the present experiments using male rats. The results were summarized as follows. 1. The supplementation of $2{\sim}4%$ garlic to 2% cholesterol diets did not affect food intake and weight gain in male rats. 2. Rat's groups fed the diets supplemented with $2{\sim}3%$ garlic (C.D.E.F) to 2% cholesterol diet (B) decreased serum total cholesterol levels by $16{\sim}32%$, triglyceride levels by $18.6{\sim}26.8%$ and ${\beta}/{\alpha}-lipoportein$ rations by $42{\sim}58%$, but increased HDL-cholesterol levels by $29{\sim}65%$ as compared to B group, and so the author assumes that garlic supplementation exerts hypocholesterolemic effect on cholesterol - fed rats because of the increase of HDL and HDL - cholesterol levels. 3. Rat's groups fed the diets supplemented with $2{\sim}4%$ garlic (C.D.E.F) to 2% cholesterol plus 0.25% bile salt diet (B) increased whole blood coagulation times, prothrombin times and fibrinolytic activities, but decreased plasma fibrinogen levels as compared to B group, and so the author assumes that garlic supplementation exerts anticoagulative effect because of the inhibition of fibrinogen synthesis in male rat's liver. 4. Rat's groups fed the diets supplemented with $2{\sim}4%$ garlic (B.C.D.E) to standard diet (A) decreased serum glucose levels by $1{\sim}24%$, but increased serum insulin concentrations by $0.5{\sim}3.0$ times as compared to A group, and so the author assumes that garlic supplementation exerts hypoglycemic effect because of the increase of serum insulin levels by stimulation pancreatic secretion of insulin from ${\beta}-cells$ in the islets of Langerhans.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1102-1106
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• 2010

This study was carried out to investigate the effect of ethanol extract from citrus peels (CP-Et) against the alloxan-induced oxidative damage on HIT-T15, Hamster pancreatic $\beta$-cell. Total polyphenol and flavonoid contents in CP-Et were $57.00{\pm}2.91\;mg/g$ and $8.11{\pm}2.83\;mg/g$, respectively. Cell toxicity on HIT-T15 by CP-Et (0.125~0.75 mg/mL) was not observed. CP-Et (0.125 mg/mL) increased cell proliferation rate of HIT-T15, which was treated alloxan ($IC_{50}=11.58\;mM$) (cell viability=$80.52{\pm}3.29%$ of normal cell, p<0.05). In comparison with insulin secretion of oxidative damaged HIT-T15, 1.5 fold ($116.93{\pm}2.11\;{\mu}g/mg$ protein) was increased by treatment CP-Et treatment (0.125 mg/mL) in HIT-T15 (p<0.05). These results showed that CP-Et contribute to repairing cells and improvement of insulin expression on oxidative stress pancreatic $\beta$-cell, and also suggested application of CP-Et as a functional food material for type 2 diabetes.

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.89-96
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• 2021

The aim of this study is to examine the effect of Caulerpa okamurae ethanol extract (COE) on glucose metabolism and insulin sensitivity as one of the drug targets for treatment of type2 diabetes. COE significantly inhibited protein tyrosine phosphatase (PTP1B) and dipeptidyl peptidase-IV (DPP-IV) enzyme activities in vitro assay. Also, COE significantly enhanced the glucose uptake and the expression of insulin receptor substrate-1 (IRS-1) and glucose transporter4 (GLUT4) proteins in 3T3-L1 adipocytes or zebrafish larvae compared with control. In dexamethasone-induced resistance model of L6 myotubes, the protein expression of insulin signaling and glucose uptake was effectively increased by the treatment of COE. In contrast, the elevated phosphorylation of IRS-1 Ser307 was normally suppressed by treatment of COE. However, COE had no effect on insulin secretion in pancreatic beta cells. Thus, our results suggest that COE improves the glucose metabolism and insulin sensitivity through the regulation of insulin signaling and GLUT4 protein in insulin's target cells and zebrafish larvae.

• Food Science and Preservation
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• v.18 no.6
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• pp.1002-1008
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• 2011

This study aimed to examine the effect of the Schizandra chinensis fruit and Morus alba leaf on insulin expression in HIT-T15 cells, which is exposed by glucose. The total polyphenol contents of the S. chinensis fruit ethanol extract and the M. alba leaf hot-water extract were $20.11{\pm}0.35$ mg/g and $50.02{\pm}0.62$ mg/mL, respectively. The S. chinensis fruit ethanol extract and the M. alba leaf hot-water extract contained $2.85{\pm}0.15$ and $8.76{\pm}0.43$ mg/g flavonoids, respectively. The antioxidant ability of the M. alba leaf hot-water extract was found to be superior to that of the S. chinensis fruit ethanol extract. Compared to the HIT-T15-treated 10 mM 2-deoxy-D-glucose, the $100{\mu}g/mL$ S. chinensis ethanol extract was found to have a two fold increase in insulin productivity. Moreover, the $100{\mu}g/mL$ M. alba leaf hot-water extract promoted the insulin secretion of high-glucose-damaged HIT-T15 almost ten fold. The above results showed that the S. chinensis fruit ethanol extract and M. alba leaf hot-water extract may improve the insulin productivity of the beta cell with glucose-induced oxidative damage. These data suggest that the S. chinensis fruit ethanol extract and the M. alba leaf hot-water extract can be used as food materials for the regulation of insulin secretion.