• Natural Product Sciences
• /
• v.19 no.4
• /
• pp.360-365
• /
• 2013

Baicalin has antioxidant, anti-inflammatory and anti-diabetic properties. IL-6 is a primary proinflammatory cytokine that contributes to impaired insulin signaling in liver. This study was carried out to investigate whether baicalin improves IL-6-mediated insulin resistance in liver. Hepa-1c1c7 cells were pre-treated with 50 and 100 ${\mu}M$ baicalin in complete media for 1 h and then cultured in the presence or absence of IL-6 (20 ng/ml). These results demonstrated that baicalin restored IL-6-suppressed expression of insulin receptor substrate (IRS)-1 protein, downregulated IL-6-increased gene expression of C-reactive protein (CRP) and suppressor of cytokine signaling (SOCS)-3, and inhibited LPS-induced production of IL-6 in Hepa-1c1c7 cells. These findings indicate that baicalin may ameliorate hepatic insulin resistance via improvement of IL-6-mediated impaired insulin signaling in hepatocytes.

• Natural Product Sciences
• /
• v.18 no.4
• /
• pp.221-226
• /
• 2012

Hesperidin (HES) is a bioflavonoid with antioxidant, anti-inflammatory and anti-diabetic properties. IL-6 is well known as a primary proinflammatory cytokine that contributes to impaired insulin signaling in liver. This study was to investigate whether HES improves IL-6-mediated impairment of insulin sensitivity in liver. Hepa-1c1c7 cells were pre-treated with 50 and $100{\mu}M$ HES in complete media for 1 h and then cultured in the presence or absence of IL-6 (20 ng/ml). These results demonstrated that HES restored IL-6-suppressed expression of IRS-1 protein, downregulated IL-6-increased expression of CRP and SOCS-3 mRNA, and inhibited LPS-induced production of IL-6 in Hepa-1c1c7 cells. These findings indicate that HES may ameliorate hepatic insulin resistance via improvement of IL-6-mediated impaired insulin signaling in hepatocytes.

• Nutrition Research and Practice
• /
• v.18 no.1
• /
• pp.46-61
• /
• 2024

BACKGROUND/OBJECTIVES: An increasing life expectancy in society has burdened healthcare systems substantially because of the rising prevalence of age-related metabolic diseases. This study compared the effects of animal protein hydrolysate (APH) and casein on metabolic diseases using aged mice. MATERIALS/METHODS: Eight-week-old and 50-week-old C57BL/6J mice were used as the non-aged (YC group) and aged controls (NC group), respectively. The aged mice were divided randomly into 3 groups (NC, low-APH [LP], and high-APH [HP] and fed each experimental diet for 12 weeks. In the LP and HP groups, casein in the AIN-93G diet was substituted with 16 kcal% and 24 kcal% APH, respectively. The mice were sacrificed when they were 63-week-old, and plasma and hepatic lipid, white adipose tissue weight, hepatic glucose, lipid, and antioxidant enzyme activities, immunohistochemistry staining, and mRNA expression related to the glucose metabolism on liver and muscle were analyzed. RESULTS: Supplementation of APH in aging mice resulted in a significant decrease in visceral fat (epididymal, perirenal, retroperitoneal, and mesenteric fat) compared to the negative control (NC) group. The intraperitoneal glucose tolerance test and area under the curve analysis revealed insulin resistance in the NC group, which was alleviated by APH supplementation. APH supplementation reduced hepatic gluconeogenesis and increased glucose utilization in the liver and muscle. Furthermore, APH supplementation improved hepatic steatosis by reducing the hepatic fatty acid and phosphatidate phosphatase activity while increasing the hepatic carnitine palmitoyltransferase activity. Furthermore, in the APH supplementation groups, the red blood cell (RBC) thiobarbituric acid reactive substances and hepatic H₂O₂ levels decreased, and the RBC glutathione, hepatic catalase, and glutathione peroxidase activities increased. CONCLUSIONS: APH supplementation reduced visceral fat accumulation and alleviated obesity-related metabolic diseases, including insulin resistance and hepatic steatosis, in aged mice. Therefore, high-quality animal protein APH that reduces the molecular weight and enhances the protein digestibility-corrected amino acid score has potential as a dietary supplement for healthy aging.

• Journal of the East Asian Society of Dietary Life
• /
• v.26 no.3
• /
• pp.278-284
• /
• 2016

Anthocyanins, a class of flavonoids, are natural water-soluble pigments, mainly found in vegetables and fruits. Anthocyanins have attractive pharmacological activities, such as anti-oxidant, anti-inflammatory, anti-cancer, and anti-diabetic effects. The purpose of this study was to investigate the inhibitory effects of the anthocyanin-rich fraction (ANF) from purple sweet potato on high fat diet-induced insulin resistance and hepatic steatosis. C57BL/6J mice were assigned to the following groups (n=8 per group): normal fat diet (NF); high fat diet (HF); high fat diet with ANF 50mg/kg (ANF50). Normal fat or high fat diets were fed for a total of 17 weeks, and ANF was orally administrated for 8 weeks (from 10 to 17 weeks, five times/week). In our results, there were no significant differences in body weight, food intake, and tissue weight upon ANF supplementation. The levels of serum triacylglycerol, total-cholesterol, and glucose were also not affected by ANF supplementation. However, ANF supplementation significantly decreased serum insulin and HOMA-IR levels as well as prevented hepatic fat accumulation in high fat-fed mice. These results show that ANF may be beneficial for improving high fat-induced insulin resistance and protecting against development of hepatic steatosis.

• The Journal of Korean Medicine
• /
• v.38 no.2
• /
• pp.53-60
• /
• 2017

Objectives: Beakdugu-tang (BDGT) consists of three medicinal herbs, and this prescription has long been used in treatment of various digestant problem in Korea. In this study, we designed to clarify mechanisms by which Korean traditional digestive medicine, BDGT, may exert anti-hepatic steatosis effects via improved insulin resistance cell model in human hepatocellular carcinoma (HepG2) and monocyte (THP-1). Materials and methods: The preparation of BDGT and constituents were extracted with 70% ethanol. HepG2 and THP-1 were treated with different concentrations of BDGT and constituents in the presence and absence of stimulants such as free fatty acids (FFAs) and oxidized low-density lipoprotein (ox-LDL), respectively. Results: The BDGT and its constituents inhibited the FFAs-stimulated lipid accumulation in HepG2 cells. Ethanol extracts of Amomum cardamomum (ACE) improved the ox-LDL induced insulin resistance in THP-1 cells. Also, treatment of monocytic cells with ACE increased anti-hepatic steatosis related gene levels including ABCA, ABCG and SR-B1. Conclusion: The results suggest that the ethanol extract of BDGT and its constituents potently inhibit the FFAs- and ox-LDL induced liver steatosis via improved insulin resistance.

• Nutrition Research and Practice
• /
• v.9 no.5
• /
• pp.472-479
• /
• 2015

BACKGROUND/OBJECTIVES: The goal of this study was to examine the effect of Sargassum coreanum extract (SCE) on blood glucose concentration and insulin resistance in C57BL-KsJ-db/db mice. MATERIALS/METHODS: For 6 weeks, male C57BL/KsJ-db/db mice were administrated SCE (0.5%, w/w), and rosiglitazone (0.005%, w/w). RESULTS: A supplement of the SCE for 6 weeks induced a significant reduction in blood glucose and glycosylated hemoglobin concentrations, and it improved hyperinsulinemia compared to the diabetic control db/db mice. The glucokinase activity in the hepatic glucose metabolism increased in the SCE-supplemented db/db mice, while phosphoenolpyruvate carboxykinase and glucose-6-phosphatase activities in the SCE-supplemented db/db mice were significantly lower than those in the diabetic control db/db mice. The homeostatic index of insulin resistance was lower in the SCE-supplemented db/db mice than in the diabetic control db/db mice. CONCLUSIONS: These results suggest that a supplement of the SCE lowers the blood glucose concentration by altering the hepatic glucose metabolic enzyme activities and improves insulin resistance.

• Nutrition Research and Practice
• /
• v.18 no.1
• /
• pp.88-97
• /
• 2024

BACKGROUND/OBJECTIVES: Mitigating insulin resistance and hyperglycemia is associated with a decreased risk of diabetic complications. The effect of Daraesoon (shoot of hardy kiwi, Actinidia arguta) on hyperglycemia was investigated using a type 2 diabetes animal model. MATERIALS/METHODS: Seven-week-old db/db mice were fed either an AIN-93G diet or a diet containing 0.4% of a 70% ethanol extract of Daraesoon, whereas db/+ mice were fed the AIN-93G diet for 7 weeks. RESULTS: Consumption of Daraesoon significantly reduced serum glucose and blood glycated hemoglobin levels, along with homeostasis model assessment for insulin resistance in db/db mice. Conversely, Daraesoon elevated the serum adiponectin levels compared to the db/db control group. Furthermore, Daraesoon significantly decreased both serum and hepatic triglyceride levels, as well as serum total cholesterol levels. Additionally, consumption of Daraesoon resulted in decreased hepatic tumor necrosis factor-α and monocyte chemoattractant protein-1 expression. CONCLUSIONS: These results suggest that hypoglycemic effect of Daraesoon is mediated through the improvement of insulin resistance and the downregulation of pro-inflammatory cytokine expression in db/db mice.

• YAKHAK HOEJI
• /
• v.56 no.6
• /
• pp.364-365
• /
• 2012

Liver is the major organ to regulate the systemic glucose homeostasis and insulin resistance. Excess energy intake leads to triglyceride accumulation in adipose tissue first and subsequent accumulation in liver, resulting in obesity and type 2 diabetes. The representative pathological animal model for obesity associated insulin resistance is a high fat diet (HFD) fed mice model. Given the essential role of liver fat accumulation in developing systemic insulin resistance in obesity, I measured the liver triglyceride contents in HFD fed mice as a function of time. As such, in this report, I show the cause and effect relationship with regard to time during a HFD feeding between a variety of factors that are related to systemic insulin resistance including glucose intolerance, plasma insulin level and inflammatory gene expression in liver and adipose tissue.

• Toxicological Research
• /
• v.21 no.3
• /
• pp.195-208
• /
• 2005

Diabetes is a major cause of morbidity and mortality, and associated with a high risk of atherosclerosis, and liver, kidney, nerve and tissue damage. Defective insulin secretion in pancreas and/or insulin resistance in peripheral tissues is a central component of diabetes. It is well established that, regardless of the degree of muscle insulin resistance, glucose levels in diabetic and non-diabetic individuals are determined by the rate of hepatic glucose production. Moreover recently studies using liver-specific insulin receptor knockout mice show the paramount role of the liver in insulin resistance and diabetes. Insulin exerts a multifaceted and highly integrated series of actions via its intracellular signaling systems. The first major section of this review defines the major insulin-mediated signaling pathways including phosphatidylinositol 3-kinase and mitogen activated protein kinases. The second major section of the review presents a summary and evaluation of methods for determination of the role and function of signaling pathways, including methods for determination of kinase phosphorylation, the use of pharmacological inhibitors of kinase and dominant-negative kinase constructs, and the application of new RNA interference methods.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1998.05a
• /
• pp.1-4
• /
• 1998

Impaired insulin action in Type 2 diabetes is thought to lead to hyperglycemia, with both environmental and complex genetic factors playing key roles. Although the primary lesion in Type 2 diabetes is unknown, a number of studies suggest that metabolic defects in the liver, skeletal muscle and fat, and pancreatic ${\beta}$-cells contribute to the disease. These metabolic abnormalities are characterized by the overproduction of hepatic glucose, impaired insulin secretion, and peripheral insulin resistance. In current pharmacological treatment of Type 2 diabetes, sulfonylurea (SU) drugs have mainly been used as oral hypoglycemic drugs to stimulate endogenous insulin secretion from ${\beta}$ cells. SU drugs, however, sometimes aggravate the disease by causing fatigue of the pancreatic ${\beta}$ cells, which leads to reduced drug efficacy after long-term treatment. This class of drugs also leads to enhanced obesity arising from the stimulation of endogenous insulin secretion in obese Type 2 diabetic patients, plus an increased incidence of SU-induced hypoglycemia. Since 1980, a major challenge has been made by us to develop a potential pharmacological therapy for the treatment of insulin resistance in peripheral tissues and/or suppression of abnormal hepatic glucose production in Type 2 diabetic patients. Such a drug would be expected to have fewer side effects and retain long-term efficacy.