Studies On Metabiolism And Pharmacokinetics Of Chiral Glucosinolates In Radix Isatidis In Vivo

Objective:Radix Isatidis is a representative traditional Chinese medicine for heat-clearing and detoxification,and has a long medicinal history.The glucosinolates（R-progoitrin,S-progoitrin,R-goitrin,S-goitrin）in Radix Isatidis are considered to be the medicinal properties.Preliminary researches confirmed that R-progoitrin and S-progoitrin are the precursor glycosides of R-goitrin and S-goitrin respectively,and R-progoitrin/S-progoitrin can biotransformate to R-goitrin/S-goitrin;R,S-goitrin is the characteristic component of Radix Isatidis,thus is chosen as the quality control index of Radix Isatidis in the Chinese Pharmacopoeia;R,S-goitrin has significant efficacy in anti-endotoxemia animal experiments,but showes no corresponding effect in cell experiments,so the possibility of metabolic activation was considered.Furthermore,there is no systematic comparative analysis of the differences in vivo and stereoselectivity of the four components,basing on the characteristics of chiral compounds.Therefore,this project takes the two pairs of chiral glucosinolates in Radix Isatidis as objects,reveals the pharmacokinetics and tissue distribution of R-progoitrin and S-progoitrin;and studies the chiral transformation and metabolites of R-goitrin and S-goitrin in Radix Isatidis in vivo,in order to improve evaluations about the process of glucosinolates in vivo.Methods:1.Establishing analytical methods to analyze the concentration of R-progoitrin and S-progoitrin in plasma and tissues respectively by using LC-MS/MS,and to obtain pharmacokinetic parameters and drug concentration in each tissue,so the differences of the blood drug concentration and tissue distribution between R-progoitrin and S-progoitrin can be compared.2.A UPC²-Q/TOF-MS method was established to determinate the chiral transformation between R-goitrin and S-goitrin,and a UHPLC-Q/TOF-MS method was used to identify the chemical structure of metabolites,thus summarizing the metabolic rules.Results:1.After oral administration,the time to peak concentration of R-progoitrin and S-progoitrin were observed at about 1.5 h(t_max).R-progoitrin and S-progoitrin were quickly cleared from the body within 2 hours.After intravenous administration,the C_max and AUC values of S-progoitrin were much higher than that of R-progoitrin,and the ratio of AUC values was about 3:1,resulting in the difference in oral bioavailability.2.The concentration in each tissue at 0.5,1.5,3,and 6 h after oral administration was analyzed.The results showed that the concentration of S-progoitrin in all tissues was higher than that of R-progoitrin.The concentration of drugs in kidney was highest except in stomach and small intestine（kidney>liver>lung>spleen>heart）,and none of them could penetrate the blood-brain barrier.3.The chiral analysis method of R-goitrin and S-goitrin by UPC²-Q/TOF-MS was established,but no chiral transformation between them was found.4.A UHPLC-Q/TOF-MS method was used to identify the metabolites of R-goitrin and S-goitrin,and 8 metabolites were identified,among which,2 metabolites were unreported metabolites.Conclusions:After oral administration,R-progoitrin and S-progoitrin were quickly absorbed from the gastrointestinal tract and were widely distributed in the body.After intravenous administration,the obvious difference in AUC values lead to a large difference in oral bioavailability,indicating that R-progoitrin and S-progoitrin had stereoseleetivity in pharmaeokineties in body.The concentration of R-progoitrin and S-progoitrin was high in all tissues.The highest tissue concentration of R-progoitrin and S-progoitrin was observed in kidney（kidney>liver>lung>spleen>heart）,and they could not penetrate the blood-brain barrier.Otherwise,R-goitrin and S-goitrin could not undergo mutual chiral transformation in body,and the main metabolic pathway of hem is amino acid combination.