Study On Isolation,Antioxidant Activity And Antimicrobial Activity Of Theabrownins From Pu-erh Tea

In this paper,the adsorption and desorption properties of different macroporous resins for pu-erh tea theabrownins was investigated,and AB-8 macroporous resins was selected for fraction.Two fractions,TBs-P1 and TBs-P2,were obtained.The two fractions were different in the contents of polysaccharide,polyphenol and protein.TBs-P2 contained more protein than TBs-P1.With using DEAE-52 cellulose chromatography,TBs-P1 fraction was separated into six fractions.The yield of each fractions were 27.40%?9.56%?4.40%?3.08%?9.36%?19.76%.We found the protein,polysaccharides and polyphenol combined tightly in TBs-P2 fraction through the Sevage experiment.TBs-P2 fraction had a concentrated molecular weight range through the Sephadex LH-20 chromatography experiment.TBs-P2 fraction was separated into four fractions through silica gel chromatography,The yield of each fractions were 56.30%?21.65%?15.1%?6.20%.The monosaccharide compositions of TBs-Pl,TBs-P2,major fractions of TBs-P1 and TBs-P2 were analysised.Each fractions were different in the contents of total sugar,total phenol and protein.The monosaccharides compositions of the major fractions were similar,and different in contents.Comparing with the water soluble pigments extracting from pu-erh crude tea,the compositions and contents of monosaccharides were significantly different.Each fractions was different in the contents of total sugar,total phenol and protein.The monosaccharides compositions of the major grading fractions of TBs-P1 and TBs-P2 were similar,and different in contents.The major monosaccharides were mannose,rhamnose,galactose and arabinose.Some fractions contained more galacturonic acid or glucose than others.Comparing with the water soluble pigments extracting from pu-erh crude tea,the compositions and content of monosaccharides were significantly different.The antioxidant activity of polysaccharides were evaluated by ABTS+ scavenging assay,DPPH scavenging assay,reducing power and ORAC.The results showed that the antioxidant activities of different fractions were different.The antioxidant activity of TBs-Pl was higher than TBs-P2,and TBs-P2A was the best in all fractions.The antioxidant capacity of sample related to the total phenol content in the samples.The study on the antimicrobial activity of Theabrownins showed that theabrownins has antibacterial effect on S.aureus,and the MIC of TBs,TBs-P1 and TBs-P2 were 6.25 mg/mL,6.25 mg/mL and 0.27mg/mL.TBs,TBs-P1 and TBs-P2 had no antibiotic effect on L.casei,L.delbrueckii,E.faecium and E.coli.TBs-P2 had stronger bacteriostasis ability than theabrownins and TBs-P1.