Beneficial effects of curcumin on hyperlipidemia and insulin resistance in high-fat-fed hamsters
ABSTRACT This study investigated the effect of curcumin (0.05-g/100-g diet) supplementation on a high-fat diet (10% coconut oil, 0.2% cholesterol, wt/wt) fed to hamsters, one of the rodent species that are most closely related to humans in lipid metabolism. Curcumin significantly lowered the levels of free fatty acid, total cholesterol, triglyceride, and leptin and the homeostasis model assessment of insulin resistance index, whereas it elevated the levels of high-density lipoprotein cholesterol and apolipoprotein (apo) A-I and paraoxonase activity in plasma, compared with the control group. The levels of hepatic cholesterol and triglyceride were also lower in the curcumin group than in the control group. In the liver, fatty acid beta-oxidation activity was significantly higher in the curcumin group than in the control group, whereas fatty acid synthase, 3-hydroxy-3-methylglutaryl coenzyme A reductase, and acyl coenzyme A:cholesterol acyltransferase activities were significantly lower. Curcumin significantly lowered the lipid peroxide levels in the erythrocyte and liver compared with the control group. These results indicate that curcumin exhibits an obvious hypolipidemic effect by increasing plasma paraoxonase activity, ratios of high-density lipoprotein cholesterol to total cholesterol and of apo A-I to apo B, and hepatic fatty acid oxidation activity with simultaneous inhibition of hepatic fatty acid and cholesterol biosynthesis in high-fat-fed hamsters.
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ABSTRACT: Xanthorrhizol, a natural compound isolated from Curcuma xanthorrhiza Roxb. (Java turmeric), has been reported to possess antioxidant and anticancer properties; however, its effects on metabolic disorders remain unknown. The aim of the present study was to evaluate the effects of xanthorrhizol (XAN) and C. xanthorrhiza extract (CXE) with standardized XAN on hyperglycemia and inflammatory markers in high-fat diet- (HFD-) induced obese mice. Treatment with XAN (10 or 25 mg/kg/day) or CXE (50 or 100 mg/kg/day) significantly decreased fasting and postprandial blood glucose levels in HFD-induced obese mice. XAN and CXE treatments also lowered insulin, glucose, free fatty acid (FFA), and triglyceride (TG) levels in serum. Epididymal fat pad and adipocyte size were decreased by high doses of XAN (26.6% and 20.1%) and CXE (25.8% and 22.5%), respectively. XAN and CXE treatment also suppressed the development of fatty liver by decreasing liver fat accumulation. Moreover, XAN and CXE significantly inhibited production of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and C-reactive protein (CRP) in adipose tissue (27.8-82.7%), liver (43.9-84.7%), and muscle (65.2-92.5%). Overall, these results suggest that XAN and CXE, with their antihyperglycemic and anti-inflammatory activities, might be used as potent antidiabetic agents for the treatment of type 2 diabetes.Evidence-based Complementary and Alternative Medicine 06/2014; 2014:205915. DOI:10.1155/2014/205915 · 2.18 Impact Factor
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ABSTRACT: High fat diet (HFD) is associated with oxidative stress induced fatty liver. Curcumin, an extract of Curcuma longa, has been shown to possess potent antioxidant and hypolipidemic properties. In this study, we investigated the effect of curcumin treatment on hepatic heme oxygenase-1 (HO-1) expression along with pro-oxidant-antioxidant status and lipid accumulation in rats fed an HFD. Male Sprague-Dawley rats were distributed among 4 groups: Group 1, which was fed the control diet (10% of total calories from fat); Group 2, which was fed the HFD (60% of total calories from fat); and groups 3 and 4, which received the HFD supplemented with curcumin and the control diet supplemented with curcumin (1 g/kg diet; w/w), respectively, for 16 weeks. HFD caused increases in hepatic lipid levels, production of reactive oxygen species, and lipid peroxidation. Further, HO-1 expression was significantly decreased. Histopathological examination showed hepatic fat accumulation and slight fibrotic changes. Curcumin treatment reduced hepatic lipids and oxidative stress parameters, and HO-1 expression was significantly increased. These findings suggest that increased HO-1 expression, along with suppressed oxidative stress as well as reduced hepatic fat accumulation and fibrotic changes, contribute to the beneficial effects of curcumin in attenuating the pathogenesis of fatty liver induced metabolic diseases.Canadian Journal of Physiology and Pharmacology 08/2014; 92(10):1-8. DOI:10.1139/cjpp-2014-0174 · 1.55 Impact Factor
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ABSTRACT: Turmeric is obtained from the plant Curcuma longa L; its major constituent, curcumin, is a polyphenol with multiple effects which can modulate some signaling pathways. Insulin resistance is a major risk factor for chronic diseases such as type 2 diabetes, atherosclerotic, metabolic syndrome and cardiovascular disease. In addition, Insulin resistance in peripheral tissue is one of the most important reasons of hyperglycemia which can cause global or systemic effects. The present study reviewed studies published in PubMed from 1998 to 2013, indicating the role of curcumin in attenuation of many pathophysiological processes involved in development and progression of hyperglycemia and insulin resistance. Curcumin can reduce blood glucose level by reducing the hepatic glucose production, suppression of hyperglycemia-induced inflammatory state, stimulation of glucose uptake by up-regulation of GLUT4, GLUT2 and GLUT3 genes expressions, activation of AMP kinase, promoting the PPAR ligand-binding activity, stimulation of insulin secretion from pancreatic tissues, improvement in pancreatic cell function, and reduction of insulin resistance. Curcumin has antihyperglycemic and insulin sensitizer effects. Thereby, more studies evaluating the effects of curcumin on hyperglycemic state and insulin resistance in related disorders such as diabetes are recommended.10/2014; 12(4):e18081. DOI:10.5812/ijem.18081