| Tea polyphenols and theaflavins are the main polyphenols in green tea and black tea respectively,and both of them have strong biological activities.The poor absorption and relative bioavailability of tea polyphenols and theaflavins from the upper gastrointestinal tract after oral administration result in the majority of the dose reaching the colon and is converted into small molecules of the phenolic acid metabolites.In addition,our previous study found that the absorption of tea polyphenols in obese animals is different from that of normal animals,which suggests that the intestinal metabolism of tea polyphenols and theaflavins in obese animals may be different from that of normal animals,too.Therefore,the research on the differential absorption,metabolism and excretion of tea polyphenols and theaflavins between normal and obese rats induced by high fat diet will be of great significance to the health effects of tea polyphenols and theaflavins in the body of obese people.In this study,the obesity model of rats was established by high fat and high sugar diet.Then the tea polyphenols and theaflavins were given to normal and obese rats everyday for ten days,respectively,and the feces were collected for 24 h after each gavage.At 30 min of post-administration in the eleventh day,the rats for each group were anaesthetized and the blood as well as the tissue were sampled.The lipid composition in the liver of rats after the intervention of tea polyphenols and theaflavins was analyzed with the high efficient and sensitive UPLC-MS system,and the differential absorption,metabolism and excretion of tea polyphenols and theaflavins in obese rats was also studied thoroughly.The main research works are summarized as follows:(1)The intake of high fat diet can alter the synthesis or hydrolysis of GPCho and TC in the liver of obese rats,which leads to the level of GPCho and TC be up-regulated.Besides,tea polyphenols can regulate the lipid composition in the liver of obese rats by reducing the levels of GPCho,GPEtn and TC,and reduce the accumulation of lipid in obese rats.The regulation of theaflavins on lipid composition in the liver of obese rats is similar to that of tea polyphenols;(2)Only EGCG,GCG and ECG are detected in the feces of rats after the intake of tea polyphenols,and the excretion of those three catechin in obese rats is significantly higher than that in normal rats(P<0.05).Besides,the excretion of TF,TF-3-G,TF-3’-G and TF-3-3’-G in obese rats is also significantly higher than that in normal rats after the intake of theaflavins(P<0.05);(3)After 10 consecutive days of drug delivery,only EGCG and GCG are detected in the plasma of normal and obese rats 30 min later after oral administration of tea polyphenols at the eleventh day,and the concentrations of EGCG and GCG in the plasma of obese rats are significantly lower than those of normal rats(P<0.05).Bsdides,no prototype theaflavins are detected in the plasma of normal and obese rats 30 min later after oral administration of theaflavins;(4)After the intake of tea polyphenols,the main phenolic acid metabolites in the feces of the rats are 4-hydroxyphenylacetic acid,4-hydroxyphenylpropionic acid and gallic acid,and the content of 3-(3,4-dihydroxyphenyl)-2-propenoic acid and 4-hydroxybenzoic acid in the feces of obese rats is significantly lower than that of the normal rats(P<0.01),while the content of 3,4-dihydroxyphenylpropionic acid,4-hydroxyphenylpropionic acid and gallic acid is significantly higher than that of normal rats(P<0.01).After the intake of theaflavins,the main phenolic acid metabolites in the feces of rats are 4-hydroxyphenylacetic acid and gallic acid,and the content of 3-(3,4-dihydroxyphenyl)-2-propenoic acid and3,4-dihydroxybenzoic acid in the feces of obese rats is significantly lower than that of normal rats(P<0.05),while the content of 4-hydroxyphenylacetic acid and gallic acid is significantly higher than that of normal rats(P<0.05).(5)After the administration of tea polyphenols,only 4-hydroxyphenylacetic acid,3-hydroxy-4-methoxybenzoic acid and 4-hydroxyphenylpropionic acid can be detected in the plasma of rats,and the concentration of 4-hydroxyphenylpropionic acid in the plasma of obese rats is significantly higher than that of the normal rats(P<0.05).After the administration of theaflavins,the concentration of 4-hydroxyphenylacetic acid in the rat plasma is significantly lower than that of normal rats(P<0.01),while the concentration of3-hydroxy-4-methoxybenzoic acid,4-hydroxyphenylpropionic acid and 4-methoxybenzoic acid are significantly higher than those in normal rats(P<0.05). |
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