Studies On The Regulation To Cholesterol Metabolism By Fucoxanthin From Brown Algae

Fucoxanthin is a kind of natural carotenoid,which has many biological activities include anti-cancer, anti-oxidation, weight loss, lowering blood pressure, anti-aging and others that can bring beneficial to human health, it is rich in brown algae. Cardiovascular disease is a critical disease which can be a serious threat to the health of human beings,mainly causes of hyperlipidemia, atherosclerosis, hypertension and others,and most of these symptoms are due to the abnormal cholesterol metabolism in vivo. Therefore how fucoxanthin in brown algaeon regulated about cholesterol metabolism in vivo were studied and analyzed in this experiment.Undariapinnitafida was used as raw material in this experiment. Fucoxanthin was extracted by organic solvent, separated and purified by silica gel column chromatography.And then high performance liquid chromatography was used to conduct qualitative analysis and quantitative detection, the concentration of wakame fucoxanthin extract was 0.717μg / μL.60 male ICR mice were used as the research object in animal experiments. High-fat model was established,low, medium and high three doses of fucoxanthin groups were set, mice in dose group were fed a dose of 80 mg / kg.d, 160 mg / kg.d, 320 mg / kg.d fucoxanthin soybean oil solution everyday, the group of positive control were gavaged 3mg / kg.d simvastatin soybean oil solution. The effects of fucoxanthin in blood lipids and liver lipid levels of ICR mice were examined.Finally,this experiment explores the regulatory mechanism about fucoxanthin on cholesterol metabolism in the mice by RT-PCR and Western blot.The results of animal experiments showed that fucoxanthin can significantly reduce(p<0.01) total cholesterol(TC),triglyceride(TG), malondialdehyde(MDA) content in ICR mice plasma and liver,increase high-density lipoprotein cholesterol(HDL-C) levels and glutathione peroxidase(GSH-Px),superoxide dismutase(SOD) vitality in plasma of the mice,in which the most significant effect of dose group is the medium group(p<0.01).At the same time it showed that low dose group can significantly increased(p<0.01) HDL-C levels and GSH-Px, SOD vitality in mice liver.Indicating that fucoxanthin can reduce blood lipid of the male ICR mice.The results of RT-PCR showed that fucoxanthin can upregulate the expression of SREBP2 in ICR mouse liver,which can be combined with HMG-COA-R gene. This process controlled the cholesterol synthesis in the liver,therefore the expression amount of HMG-COA-R in the liver was decreased. Meanwhile,fucoxanthin can upregulate the expression of LDLR in mice,prompt rapid metabolism of LDL-C to prevent atherosclerosis. In addition, fucoxanthin can inhibit the expression of ACAT in mice liver tissue, inhibit the absorption of cholesterol in the liver.Through upregulating the expression of CYP7A1 gene, fucoxanthin can prompt a portion of the liver cholesterol into bile acids which can flow right out of the body,thereby reducing cholesterol levels in mice liver.The results of western blot showed that SREBP2 and LDLR protein expression was increased in fucoxanthin-dose group which compared with the model group.On the other side,HMG-COA-R protein expression was decreased,which is consistent with the results of RT-PCR. These results indicated the regulation mechanism of fucoxanthin on cholesterol metabolism in the liver of mice.