The Hypoglycemic Activity Of Polyphenols Extracted From Mulberry(Fructus Mori L.) Fruit

Mulberry as a typical traditional homology of medicine and food in China,has various functions.We studied the mulberry polyphenols responsible for bioactive activities in order to provide theoretical and methodological support for the development of mulberry products.(1)Higher content of phenolic compounds,stronger antioxidative,and α-Glucosidase inhibition activities were obtained in colloid mill-processed juice.The extraction kinetics of marc was investigated under three conditions(stirring,ultrasound,and combined stirring and ultrasound).The optimum extraction condition for gear juicer marc was the combination of ultrasound with stirring for half an hour.While ultrasound for one hour was optimized for the extraction of colloid mill marc.Total polyphenols and monomeric anthocyanin obtained from colloid mill-processed samples were 46% and 68 % higher than the gear juicer-processed,respectively.(2)The effect of solvent polarity on the profile and bioactive activities of mulberry polyphenol(MP)were conducted.Results indicated that EtOH/AA/W(ethanol/ acetic acid/water)took advantage in obtaining the highest MP yield(49.81 mg GAE g-1 dw),and cellular antioxidant capacity in the PBS no-wash protocol(63.2 μmolQE/100 g),as well as low cell cytotoxicity(≥50.0 mg m L-1).ME2CO/AA/W(acetone/ acetic acid/water)was the best solvent for MP extraction with the richest MP compositions(two phenolic acids,four anthocyanins and four flavonols),greatest potential in inhibiting proliferation of HepG2 cells(EC50 = 28.2 mg m L-1)and highest intracellular antioxidant activity(38.0 μmol QE/100 g).(3)We explored the comprehensive profile of mulberry(Morus alba L.)fruit polyphenols and revealed the novel anti-diabetic constituents.A total od fortyseven phenolic compounds were identified and quantified.Twenty-one compounds were first reported in mulberry fruit,such as delphinidin 3-rutinoside-5-glucoside and cyanidin 3-rutinoside dimer.Hierarchical cluster analysis and pearson correlation coefficients revealed that syringic acid and galloylcyanidin-glycoside contributed most to inhibit α-glucosidase activity;quercetin and cyanidin-glycosides were essential for cellular antioxidant activity;dihydroquercetin and 1,5-dicaffeoylquinic acid were the main contributors to protect RIN-m5 F cells against glucotoxicity.(4)We studied the stability of mulberry polyphenols(MP)under the simulated gastric,small intestine and large intestine digestion.We also studied the effect of MP on the decomposition of oil in simulated small intestine digestion.Results showed that MP kept stable in gastrointestinal tract.The higher polyphenol concentrations in the digestive juice of small intestine,the weaker fat catabolism ability.MP may join force to change the rheological properties of digestive juices,such as raising the oil droplet diameter,and increased viscosity of the digestive juices,which led to reduced fat decomposition.(5)We explored the potential path ways in hypoglycemic activity of mulberry polyphenols(MP)from the perspective of gut microbita.Results indicated that after being givening MP for eight weeks,gut microbial diversity and contents had been changed.Compared with the control group,the gut microbita diversity of MP treated mice were improveed.MP treated groups showed restored bacteria in phylum,order,class,family,genus,species and OTUs levels.The gut bacteria composition of MP treated mice showed a tendency to be close to the normal group.The MP groups showed higher abundance of Bacteroides(increased by 8%),which was favored to produce higher contents of butyric acid and propionic acid.MP administration significantly reduced the abundances of Firmicutes and Bacilli by 12% and 40%,respectively.The improvement in liver metabolism and antioxidant activity were conducive to maintain the glucose equilibrium(improved expression in GLUT-4)and abating insulin resistance(lower serum insulin and pancreatic tissue repair).The 16 S function prediction analysis pointed out that the improved metabolism might be introduced by gut bacteria through adjusting the catabolism of carbohydrates and amino acids,as well as the express of ABC transporters.