Research On The Metabolic Kinetics Of Catechin And Its Effect On The Enzymes CYP3A4and Aromatase

The biological activity of catechin is in the ascendant. Its anti-oxidation,anti-cancer activity all depends on the EGCG pharmacodynamics in vivo (absorption,distribution, metabolism, excretion)and high bioavailability.The observation ofcatechin dynamic changes in the body,evaluate its absorption, distribution andpharmacokinetics characteristics can provide a theoretical basis for the furtherdevelopment of tea and related products. The research of scholars at home andabroad are focus on catechin extraction, purification content of active ingredients andpharmacological activity, but studies on the comparison of catechin metabolism invivo and its intervention mechanism of the related metabolism enzyme has beenrarely reported.The task treat the adult male and female ICR mice as the research objects,established the catechin EGCG RP-HPLC detection method of the mouse plasma,liver, spleen, kidneys and urine. Meanwhile we compared the catechin EGCGelimination pharmacokinetic characteristics in these tissues, explored the catechinEGCG distribution and elimination rule in different tissues. Use the establisheddetection methods and the clarified kinetics law, we put forward the envisage ofbioavailability enhancement catechin oral solution. Finally, with the help of PCR,fluorescent immunohistochemical biological molecules technology we explored theEGCG intervention mechanism of the related metabolism enzyme.1．The Research on the metabolic dynamics and tissue distribution of catechin EGCGin mice.Used the SPF adult ICR male mice, collected the organization, feces and urine,homogenate at different time points after intraperitoneal inject EGCG, through theliquid-liquid extraction, establish a HPLC method to detect the contents of EGCG,calculate the catechin EGCG distribution and eliminate rule in the body. The resultsshowed that:(1) the established HPLC method in the linear detection range has a good linear relationship(r>0.999), the average recovery rate above80%, intra-dayand inter-day precision were lower than15.0%.(2) compared the distribution,metabolism and elimination rule of catechin in vivo. EGCG distributed in mouseplasma, liver, spleen, kidneys, and testes. The eliminated EGCG from the feces andurine during0-24h below the10%of the EGCG total dose. Its mainly metabolic typewas I phase hydrolysis reaction, II phase hydrolysis combines products can beenfound in the small intestine and liver. Through the research on the metabolicdynamics and tissue distribution of catechin EGCG in mice, catechin EGCG iswidely distributed in mouse tissues, eliminated fast, less excretion in feces and urine,most of EGCG were metabolized in vivo.2. The gender difference of catechin EGCG metabolic kinetics and acute liver injuryin miceThe SPF male and female ICR mice(25±2g) were tested by the " The Research onthe metabolic dynamics and tissue distribution of catechin EGCG in mice", basedon the established RP-HPLC analyse we found EGCG in male mice elininatedfaster than the females and the elimination half-life is shorter, changes in serumenzyme activity after dosing detection kit, the results showed alanineaminotransferase (ALT), lactate dehydrogenase (LDH) were significantly increased(P <0.05)both in male and female mouse serum, females was significantly higher thanin male mice (P <0.01), succinate dehydrogenase (SDH) and ornithine carbamyltransferase (OCT) had no significant change in content. Fluorescence microplatedetection of liver mitochondrial membrane potential showed the changes in female ratliver was significantly higher than in male mice. Fluorescenceimmunohistochemistry detected the gender difference of hepatocytescarboxylesterase II content, the results showed that the carboxylesterase II is themajor enzymes of EGCG hydrolysis reaction and the contents of carboxylesterase IIwas higher than in females.3. EGCG effect on the enzymes CYP3A4and testicular aromataseUsed the RT-PCR technique to detect the effect of catechin EGCG on the livermetabolic enzymes CYP3A4and leydig cells Aromatase mRNA,Immunofluorescence analys the impact of chemical technology organizations of their protein expression. The results showed that EGCG in mouse liver and testes aredistributed well. Catechin significantly induced the metabolizing enzyme CYP3A4expression in the liver, but the testicular aromatase gene expression significantlyinhibited.4. Enhanced bioavailability oral catechin liquid preparation and its metabolic kineticparameters calculation.Based on the different material screening, PEG400was filtered as the materialscan be improved the oral bioavailability of catechin.The bioavailability of this oralliquid was evaluated in vivo. Used the overall intestinal absorption experimentalanimal models, quantitative detected the EGCG absorption in the small intestine.The measurement results obtained that EGCG standard curve was Y=12037x+560.3(r=0.9999) in0.1-200mg/L concentration range,the high, middle and lowconcentrations of catechin recoveries were more than85%in the range of thestandard curve, intra-day and inter-day precision were less than8%. It indicated thatusing PEG400as catechin absorption accelerator can accelerat the EGCG enter intothe blood through the intestinal epithelium cycle,compared with the conventionalformulation of catechin, catechin absorbing capacity was improved in this way.In this paper, research on the metabolic dynamics of catechin and its effect onthe enzymes were studied by the metabolic dynamics and tissue distribution, thegender difference of catechin EGCG metabolic dynamics in mice, enhancedbioavailability oral catechin liquid preparation and the metabolic kinetic parameterscalculation, the effect on the metabolism enzymes CYP3A4and testicular aromatase.These work has reference value to catechin pharmacokinetics research, What’s more,it can provide a theoretical basis for the development of catechin-related health careproducts and new drug formulations.