Effects Of Polyphenols From Kiwifruit Peel On The Lipid Metabolic In High Fat Diet Rats

Objective: In order to explore the material basis and health effect mechanism of kiwifruit polyphenols and guide the development and utilization of kiwifruit resources.We analyzed the composition of polyphenols in different parts of kiwifruit.Then,the effects of kiwifruit peel polyphenols on lipid metabolism in rats with high fat diet and its mechanism were explored.Methods: 1.Identification of the composition of kiwifruit polyphenols: establish an HPLC method for the determination of kiwifruit polyphenols,and analyze the components of the four parts of kiwifruit peel,stem,leaf and pulp.2.In animal experiment,32 male SD rats were randomly divided into four groups,including normal control group(NC group),high-fat diet group(HF group),kiwifruit peel polyphenol low-dose intervention group(LKP group),high-dose intervention group(HKP group).The body weight and food intake of each week were recorded.At the end of the experiment,HDL-C,LDL-C,TG,TC,FFA,AST,ALT in serum and TG,TC in liver were measured;and MDA,SOD,GSH,CAT in liver were measured.Through UPLC-Q-TOF-MS technology and multivariate statistical analysis,the liver lipid metabonomics was determined,and the potential lipid markers were identified to determine the effect of kiwifruit polyphenols on the lipid composition of high-fat diet rats.Expression of ACC,FAS,GPAT,DGAT1,DGAT2,FATP-2,PPAR ? and AMPK,PGC-1 ?,PPAR?,CPT-1? mRNA were detected by real time PCR.Results: 1.Identification of the composition of kiwifruit polyphenols:Seven kinds of polyphenols were identified by HPLC: Gallic acid,protocatechuic acid,chlorogenic acid,esculetin,catechin,epicatechin,p-coumaric acid.The composition of kiwifruit polyphenols has different parts.The main components of kiwifruit peel,stem and leaf polyphenols are protocatechuic acid,esculetin and gallic acid,while the main components of fruit pulp are epicatechin.The contents of total phenols in peel,stem,leaf and pulp of kiwifruit were 22.14mg/g,6.80mg/g,9.96mg/g and 9.37mg/g.The content of polyphenols in peel of kiwifruit was the highest.2.Effects of kiwifruit Peel Polyphenols on growth performance and antioxidant level of rats fed with high-fat diet: kiwifruit Peel Polyphenols was effectively inhibit the increase of body mass and fat mass of rats fed with high-fat diet;compared with HF group,HKP group was significantly reduce AST activity in serum(P< 0.05);LKP and HKP group was significantly enhance SOD and CAT activity and reduce MDA content in liver(P< 0.05).3.The effect of kiwifruit peel polyphenols on lipid composition of rats with high fat diet: compared with HF group,kiwifruit peel polyphenols was significantly reduce the content of TG,LDL-C and FFA in serum of rats,and significantly improve the level of HDL-C(P < 0.05),and the content of TG in liver was significantly decreased(P < 0.05).The results of liver lipomics showed that: Compared with HF group,HKP group significantly decreased the contents of TAG,DAG,FA,Cer,and significantly increased the levels of SM,FAHFA,PC,PE(P < 0.05);Kiwifruit Peel Polyphenols was improve the disorder of lipid metabolism by intervening the metabolism pathway of glycerides,sphingolipids and glycerophospholipids.4.The mechanism of kiwifruit peel polyphenols on lipid metabolism disorder in rats with high-fat diet: in order to further clarify the reason of kiwifruit peel polyphenols on fat composition,the mechanism of lipid absorption,synthesis and oxidative decomposition were analysised.Compared with the normal group,the mRNA expression of lipid absorption and synthesis genes in HF group was significantly increased,and the mRNA expression of genes related to oxidative decomposition was significantly decreased.After the intervention of kiwifruit peel polyphenols,HKP group significantly reduced the expression of ACC,FAS,GPAT,DGAT1,DGAT2,PPAR ?mRNA(P < 0.05),significantly increased the expression of AMPK,PPAR ?,CPT-1 and PGC-1 ? mRNA(P < 0.05),while LKP group mainly reduced the expression of FAS,increased the expression of PPAR?,CPT-1(P < 0.05)compared with HF group.Conclusion: the content of polyphenols in kiwifruit peel is the most abundant,which can increase the development and utilization of the peel polyphenols;Kiwifruit Peel Polyphenols can regulate the disorder of lipid metabolism and enhance the antioxidant capacity of liver.The mechanism of kiwifruit PeelPolyphenols regulating lipid metabolism may is related to inhibiting the absorption and synthesis of lipids and promoting the decomposition of lipids.This study suggested that kiwifruit Peel Polyphenols have the health effect of regulating lipid metabolism disorder,it is developed and utilized in future.