Prevention Of Kiwi Seed Polyphenols On Obesity Of Mice Induced High-fat Diet And Its Mechanism

Kiwi fruit(Actinidia chinensis Planch.)is a perennial deciduous vine belonged to Actinidia Lindl-Actinidiaceae which has advantages of widely-distributed,nutrient-rich,medicinal,and edible.Industrial processing produces a lot of by-products,of which the annual output of kiwifruit seed exceeds 150,000 tons(Shaanxi).Except for a small amount used for animal feed and oil processing,most of them are discarded,causing great waste of resources and environmental pollution.Obesity is a chronic metabolic disease charactered by increased fat accumulation derived from the imbalance of energy intake and consumption.Studies have found that plant polyphenols can prevent obesity or other related diseases by regulating,controlling or inhibiting some cell signaling pathways related with lipid metabolism.Can kiwi seed polyphenol effectively prevent obesity? To verify this hypothesis,the thesis will use kiwi seed polyphenol extracts to intervene a high-fat diet-induced obese mouse model for 12 weeks,from the perspective of glucose and lipid metabolism and intestinal flora,to explore the action mechanism of obesity prevention.Our results provide data support and theoretical basis for the intensive processing of kiwifruit seed and the realization of high value and efficient use.The main results are as follows:1.UPLC-MS/MS analysis results showed that the crude extract of kiwi seed polyphenol is rich in fraxetin,caffeic acid,salicylic acid,2-pyrocatechuic acid,isoferulic acid,isoscopletin,luteolin,kaempferol 3-a-D-glucoside,aesculetin,quercetin,quercitrin,rhododendrol,kaempferol,homovanillic acid,afzelin,4-hydroxycinnamic acid and 4'-O-methylpuerarin,in total of 17 polyphenolic compounds.2.Kiwi seed polyphenol intervention can alleviate the weight gain and fat accumulation in mice;improve glucose tolerance and insulin sensitivity in mice;remit fatty vacuoles,infiltration of inflammation in liver tissues and adipose tissue damage;reduce inflammatory cytokines-related indicators(IL-6,IL-10,IL-1b,and TNF-a)levels in serum,liver,and colon,effectively inhibiting the release of inflammatory cytokines in the body;decrease lipid metabolism-related indicators(LDL-C,HDL-C,TC,TG,AST,and ALT)levels,regulating the balance of lipid metabolism;up-regulation of UCP2 gene related to body heat production and PPAR-g gene related to fat differentiation,down-regulation of PPAR-a,CPT-1,SIRT-1 related to fatty acid b-oxidation and SREBP-1c,FAS,and LXR-a genes related to fat synthesis indicated that kiwi seed polyphenol can alleviate obesity-induced glucose and lipid metabolism disorders by stimulating body heat production,regulating fat synthesis and decomposition,futher preventing obesity induced by high-fat diet.3.The intervention of kiwi seed polyphenol can increase the content of short-chain fatty acids,increase the ratio of Firmicutes to Bacteroidetes and change the species composition and abundance of intestinal flora,thereby preventing obesity induced by high-fat diet.