The Modulatory Effect Of Phenolic Compounds From Naked Oat On Decreasing Blood Glucose,Lipid And Intestinal Microbiota

Naked oat is planted the most widely in China.Natural active substances of naked oat compounds have a certain effect on improving glucose and lipid metabolism in the body.In this study,the extraction,purification process and component identification of phenolic compounds from naked oat is researched.It further explores its regulation of blood glucose and lipid metabolism in vitro and in vivo.The main conclusions are listed as follows:1.The AB-8 macroporous resin purification process of naked oat phenolic compounds was optimized by response surface methodology.The best process parameters for static adsorption-desorption are:adsorption time is 8.238 h,desorption time is 4.265 h,material-liquid ratio is 1:11.926 g/mL,and ethanol volume fraction is 90.368%.The adsorption amount of naked oat phenolic compounds was 33.85 mg/g and the desorption rate was 94.44%.The lower the degradation temperature and the longer the degradation time,the smaller the Mw of the naked oat?-glucan.When the enzyme addition amount was 0.05%and the water bath treatment time was 1 h,an oligomeric?-glucan with a relative molecular mass of 6.8×10⁴ Da was obtained.2.Free and bound phenolic compounds were fractionated with ethyl acetate,n-butanol and aqueous.UPLC analysis was determined the composition of each fraction of the phenolic compounds.There was a negative correlation between the yield and the total phenolic content of each fraction.The combined total phenolic content of the ethyl acetate fraction was 363.65±1.42mg GAE/g,which was higher than those of other fractions,while the type and number of phenolic acids in the phenolic compounds in the aqueous fraction were the least.Ferulic acid,caffeic acid and p-hydroxybenzoic acid are the three main types of phenolic compounds in naked oat phenolic compounds,meanwhile rutin and apigenin are the two main types of flavonoids in naked oat.It was found that n-butanol bound phenolic compound fraction(IC₅₀=98.39±0.89?g/mL)had the strongest ability to DPPH scavenge.3.Kinetic analysis of the interactions between anti-digestive enzymes(?-amylase and?-glucosidase)and anti-digestive effects of naked oat compounds.Semi-purified phenolic compounds have a reversible competitive inhibition of?-glucosidase,while all organic phenolic compounds fractions have the property of mixed inhibitors against?-amylase and?-glucosidase.In addition,the starch hydrolysis of n-butanol fraction of naked oat compound was significantly lower than that of other fractions in vitro.4.The cookie model and sugar-protein simulation system were established to explore the inhibitory effect of naked oat phenolic compounds on fluorescent AGEs and its dose-effect relationship.The results indicated that naked oat phenolic compounds showed good anti-glycation ability in cookies model and simulated systems.The fluorescent AGEs inhibition rate of the ethyl acetate fraction reached a maximum of 68.07%;in BSA-Glu,when the mass concentration was400 and 500?g/mL,the inhibitory effects of phenolic compounds in ethyl acetate fraction and n-butanol fraction on fluorescent AGEs were higher than aminoguanidine.In addition,three pure phenols were analyzed,luteolin has the best inhibitory effect on BSA-Glu system fluorescent AGEs,while caffeic acid has the best effect on Fru-Cys and Fru-Lys system fluorescent AGEs.5.The effects of naked oat compound and its complex with?-glucan on humanized bacterial obese mouse model are measured.The results showed that oral administration of oat phenolic compounds for 8 weeks could slow down the weight gain of obese mice caused by high-fat diet and had significantly effect on controlling the blood glucose level,reducing the levels of TC,TG,LDL-C,increasing the levels of HDL-C in the serum(p<0.01),slowing down the symptoms of hyperlipidemia in obese mice.The effect was positively correlated with the dose concentration.Furthermore,OPC could significantly reduce the deposition of lipids in the liver tissue and make liver lipid metabolism function normal of the mice.By intervention of OPC and OBG for 8 weeks,it revealed that the intestinal microbial diversity of obesity mice was improved.The relative abundance of Bacteroidetes was increased,the relative abundance of Firmicutes and the F/B ratio were reduced.Naked oat compound and its complex with?-glucan reduced the risk of hyperlipidemia in mice by regulating the composition of the gut microbiota.