Activity And Mechanism Of Several Marine Active Substances In The Prevention Of Faty Liver

Morbidity of nonalcoholic fatty liver disease(NAFLD)has increased year by year because of the irrationality dietary structure and lack of daily exercise.NAFLD has turned into an usual chronic metabolic syndrome that could threaten human health,its clinical symotom is functional disorder of liver caused by the accumulation of triglyceride(TG).NAFLD is a kind of dynamic developmental syndrome NAFLD that also not benign,in the early days of simplex accumulation of lipid in hepatocyte,some usual medicines which have lipid-lowering effect clinically could reduce the intercellular lipid content reversibly,but the price is liver function damage.According to reports,some kinds of dietary nutrition factors could regulate the lipid metabolism in liver in a certain extent through specific pathways such as accelerate the β-oxidation in mitochondria and inhibit the synthesis of fatty acid in hepatocyte.Studies also found that there were many kinds of antioxidant ingredients,like polyphenols,pigments and so on,in some marine organisms,but reports about the lipid-lowering effect of these antioxidant ingredients were not much.For the development of functional foods with efficient lipid-lowering capacity and the remission of NAFLD symptom,fucoxanthine,taurine and brown algae polyphenol were taken as raw materials to study the lipid-lowering efficacy and mechanism of these active substances both in vivo and in vitro.Main conclusions are as followed:1.Extraction and purification of brown algae polyphenols from kelp and component identification: ethyl alcohol extraction and continuous solid phase extraction through XDA-7macroporous resin and silicone were used to extract brown algae polyphenol in kelp power,the purity was measured by HPLC.Results showed that the purity of brown algae polyphenol was 20.64 % and the impurity content was relatively low.Time of this extraction process was shorter than traditional method and improve the shortcoming of column chromatography which should take a long time and led to a sharp fall of ployphenol.Then preparative HPLC was taken to further purification of brown algae polyphenol,then the principal component called Dieckol in brown algae polyphenol extracted from Fujian kelp was confirmed by LC-MS and its molecular weight was 742.2.Simplex accumulation of lipid in hepatocyte was taken as in vitro model to evaluate the lipid clearance effect and mechanism of fucoxanthine,taurine and brown algae polyphenol:0.50 mmol/L OA was used to induce and stimulate HepG2 cells for 24 h,lipid content in cells was six times as blank group and without inflammation,NAFLD in vitro model was established on this condition.Fucoxanthine,taurine and brown algae polyphenol was used to intervene NAFLD in vitro model,results showed that when active substances intervene for24 h and concentration was 1μg/mL,the lipid clearance rate in cells of fucoxanthine,taurine,brown algae polyphenol and its autophage was 23 %,13 %,36 %and 23 % respectively while compared with model group;when active substances intervene for 48 h,the lipid clearance rate had risen to 61 %,56 %,57 % and 54 % respectively;but there was no significant difference between intervene for 72 h and 48 h.It indicated that it needed a set amount of time for active substances to play their role in lowering lipid,and they had a certain subsidiarity in the lipid clearance of cells own.Then the content changes of several correlation factors AMPK,PPARα and CPT-1 were taken to analyze the lipid-lowering mechanism of active substances,and had found that active substances could improve the content of AMPK,PPARαand CPT-1 after several intervene time,lowering lipid by enhancing β-oxidation.3.Study on the assessment and mechanism of lipid-lowering efficacy in vivo of brown algae polyphenol extractive: high-fat diet was used to feed ICR mice for 4 weeks,the TG content and LDL content of mice liver from model group was 2.61 and 1.17 times as blank group respectively,and there were no significant change in inflammatory factor ALT and AST;the tendency had not change when feeding time was prolonged,it indicated that simplex accumulation model of lipid in hepatocyte had well stability.Mice intervened by brown algae polyphenol extractive and without sitimulation of high-fat diet in a short period(4 weeks),the lipid clearance had reached 76 %.As comparation,the lipid clearance was 59 % in mice without sitimulation of high-fat diet and relyed on its own liver metabolism,and the highest lipid clearance was 53 % when the feeding time of mice with high-fat diet was prolonged.It indicated that despite the lipid-lowering effect of organism,brown algae polyphenol extractive had a certain assessibility,so it could decrease the accumulation of lipid in a short time if organism refrained the intake of high fat diet and accepted the intervention of brown algae polyphenol.The lipid-lowering mechanism of brown algae polyphenol was analyzed and found that the lipid metabolism in vivo of brown algae polyphenol extractive may through AMPK-CPT-1 pathway,and had increased the fatty acid β-oxidation in liver cells mitochondrial and accelerated the catabolism of fatty acid.