| Pu-erh tea is the special type of Chinese dark tea of Yunnan province.It is representative dark tea which is one type of Chinese six teas.Among these teas,Chinese dark teas are fermented by microorganisms.With the development of the marketing of Puerh tea,and the people's concerning on the health,value of food and beverage,the research on the health function of Pu-erh tea has been further developed.Thought the study,the scientists found that Pu-erh Tea have apparent health functions in anti hypertensive and lipid-lowering,hypoglycemic,prevent arteriosclerosis,anti-fatigue,anti-cold,antibleeding,anti-cancer,anti-hepatitis and other aspects.It showed that the chemical composition of Pu-erh tea have rich biological activities.Because Pu-erh tea belongs to the post-fermented tea,the post-fermentation has an important influence on chemical composition changes.Pile-fermentation is the key technology in the processing of Pu-erh tea,and produces the special components tea pigments,that is theabrownine.As the time of extending,the content of the theaflavins and thearubigins are decreased gradually,the content of theabrownine is increased gradually and become the main component in tea pigments.Generally,theabrownine is that theaflavin and thearubigin after further oxidation from to high performance polymer,its structure is extremely complex and composition which have not known yet.EGCG is the most important polyphenol active ingredients in green tea,the study on its biological activity is circumstantial,especially of the aspect of lipid-lowering.Both of Pu-erh tea and green tea have the effect of lipid-lowering,but the specific effective active ingredients in vivo is not clear.Because of the unknown structure of theabrownine,relatively studies is less known.At present,the study is mainly on intestinal flora metabolism which is concentrated about the chemical constituents of traditional Chinese medicine,and the current results of research showed that prototype component can become the metabolites with better pharmacological and toxicological activities with an action of intestinal flora metabolism.In the study,this study aims to explore the microbial metabolites of theabrownine and EGCG by gut microflora,which may have the common function of lipid-lowering mechanism of Pu-erh tea and green tea.Theabrownine was prepared in our laboratory,and Pu-erh tea and EGCG were used as the experimental materials for in vitro intestinal flora metabolism experiment.Use UPLC and LC-MS,analyzed metabolites of theabrownine and EGCG under the effect of intestinal flora in rat.By the experiment,we obtained the following conclusions:(1)Under the anaerobic fermentation of intestinal flora,EGCG was metabolized into phenolic acid and catechin.After 72 hour of metabolism,EGCG produced 5 metabolites:gallic acid,3-O-methylgallic acid or 4-O-methylgallic acid,4-hydroxyphenylpropionic acid and epicatechin gallate.These metabolites are relatively stable,and with time changes,these metabolites variation trend has rule,conform to the metabolic dynamics model.(2)Theabrownine metabolites by intestinal flora included gallic acid,3-Omethylgallic acid or 4-O-methylgallic acid,4-hydroxyphenylpropionic acid,catechin,gallocatechin or(-)-epigallocatechin and theobromine.But with the change of time,its metabolites are not stable.(3)Through experiments and result analysis,preliminary explanation,under the action of intestinal flora,theabrownin and EGCG can produced same metabolites: gallic acid,3-O-methylgallic acid or 4-O-methylgallic acid,4-hydroxyphenylpropionic acid.The reason of Pu-erh tea and green tea has the same function about lipid-lowering that their main chemical composition: theabrownine and EGCG can produce same metabolites.(4)Through quantitative detection,found the change tendency of EGCG and gallic acid in the process of metabolism.The content of EGCG decreased rapidly after 24 h in metabolism,the content of gallic acid increased significantly before 12 h and its decreased rapidly after 36 h. |
PDF Full Text Request