Purple sweet potato anthocyanins attenuate hepatic lipid accumulation through activating adenosine monophosphate-activated protein kinase in human HepG2 cells and obese mice.
ABSTRACT Purple sweet potato is a functional food rich in anthocyanins that possess disease-preventive properties. Anthocyanins are known to possess potent antidiabetic properties. However, the effect of the anthocyanin fraction (AF) from purple sweet potato on hepatic lipid metabolism remains unclear. Our hypothesis is that AF inhibits hepatic lipid accumulation through the activation of adenosine monophosphate-activated protein kinase (AMPK) signaling pathways in vitro and in vivo. In this study, we evaluated body weight, liver histology, and hepatic lipid content in high-fat diet (HFD)-fed ICR mice treated with AF. In addition, we characterized the underlying mechanism of AF's effects in HepG2 hepatocytes through Western blot analysis. Anthocyanin fraction (200 mg/kg per day) reduced weight gain and hepatic triglyceride accumulation and improved serum lipid parameters in mice fed an HFD for 4 weeks. Anthocyanin fraction significantly increased the phosphorylation of AMPK and acetyl-coenzyme A carboxylase (ACC) in the liver and HepG2 hepatocytes. In addition, AF down-regulated the levels of sterol regulatory element-binding protein 1 and its target genes including ACC and fatty acid synthase (FAS). The specific AMPK inhibitor compound C attenuated the effects of AF on the expression of lipid metabolism-related proteins such as SREBP-1 and FAS in HepG2 hepatocytes. The beneficial effects of AF on HFD-induced hepatic lipid accumulation are thus mediated through AMPK signaling pathways, suggesting a potential target for the prevention of obesity.
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ABSTRACT: This study was performed to investigate the effects of ethanolic extract of Ulmus davidiana root (UE) on lipid metabolism in mice fed a high-fat diet (HF) for 7 weeks. Forty male ICR mice were randomly divided into four groups; normal diet group (N), high-fat diet group (HF), HF with 0.5% UE (HF-L) and 1% UE (HF-H) group. Body weight, body weight gain, and liver weight in the HF group was significantly higher than in the N group, while those of the HF-L and HF-H group were unchanged. UE improved HF-induced dyslipidemia by reducing serum triglyceride, total cholesterol, and the atherogenic index. There was no difference in serum HDL-cholesterol among experimental groups. However, the HDL-cholesterol/total cholesterol ratio was significantly increased in the HF-L and HF-H group. Histological analysis showed that HF-fed mice developed hepatocellular microvesicular vacuolation as a result of fat accumulation. These changes were attenuated by 1% UE supplementation. In addition, hepatic triglyceride and cholesterol levels in the HF-H group significantly reduced. Taken together, these results demonstrated that lipid levels in the blood and liver were reduced by UE, suggesting that it might be beneficial for the prevention and treatment of hyperlipidemia and fatty liver.The Korean Journal of Food And Nutrition. 03/2013; 26(1).
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ABSTRACT: The adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway arose early during evolution of eukaryotic cells, when it appears to have been involved in the response to glucose starvation and perhaps also in monitoring the output of the newly acquired mitochondria. Due to the advent of hormonal regulation of glucose homeostasis, glucose starvation is a less frequent event for mammalian cells than for single-celled eukaryotes. Nevertheless, the AMPK system has been preserved in mammals where, by monitoring cellular AMP:adenosine triphosphate (ATP) and adenosine diphosphate (ADP):ATP ratios and balancing the rates of catabolism and ATP consumption, it maintains energy homeostasis at a cell-autonomous level. In addition, hormones involved in maintaining energy balance at the whole-body level interact with AMPK in the hypothalamus. AMPK is activated by two widely used clinical drugs, metformin and aspirin, and also by many natural products of plants that are either derived from traditional medicines or are promoted as "nutraceuticals." Expected final online publication date for the Annual Review of Nutrition Volume 34 is July 17, 2014. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.Annual Review of Nutrition 09/2012; · 10.46 Impact Factor
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ABSTRACT: Thermal and storage stabilities of red radish anthocyanins (RRAs) in various juice beverages (apple, grape, peach, pear, pomegranate and lemon) were studied over temperature range 70–90 °C and 4–25 °C. RRAs degradation in all juice beverages followed first-order reaction kinetics. RRAs showed a much faster degradation rate during storage at room temperature (t 1/2 value ≤84.0 days) than did in refrigerated temperature (t 1/2 ≥value 130.9 days). The rate constant (k), E a and Q 10 values for RRAs in juice beverages varied from 1.33 to 0.33, 47.94 to 14.77 kJ mol−1 and 1.16 to 1.89 at 70–90 °C. During heating, RRAs in peach and pomegranate showed higher stability than others at these temperatures. There was a positive correlation (R 2 > 0.9128) between ascorbic acid content of juice beverages (8–36 mg/100 mg) and stability of RRAs at 70–90 °C. It was found that RRAs in apple and pear juice beverage were more stable than in other juice beverages.European Food Research and Technology 01/2014; 238(2). · 1.39 Impact Factor