Study On The Mechanism Of Licorice Detoxification Inprescription Of Tiaowei-Chengqi Decoction Based On Gastrointestinal Metabolism And Transport Of Anthraquinones

Tiaowei-chengqi decoction is composed of Rhubarb,Licorice,Sodium Sulfate,which,a classical prescription,commonly used in clinical practice for treating constipation.However,the underlying principles for governing the formulation of Tiaowei-chengqi decoction remain unknown.This study aimed to investigate the metabolism of anthraquinones by human fecal bacteria to clarify the relationship between their chemical structural characteristics and intestinal metabolism.Besides,we used a Caco-2 cell monolayer model to explicate the possible compatibility mechanism of Tiaowei-chengqi decoction on the uptake and transport of rhein from the perspective of intestinal absorption.Besides,the study on comparing the toxicity between rhein and rhein accompanied by Licorice water extract on HK-2 cells was carried out in different dose,and the change of morphology,OD of LDH and NAG,cell cycle and apoptosis were detected.The results are as follows.A total of ten metabolites were identified,six of which were first detected on the basis of the exact mass by human fecal bacteria in this work.In particular,the metabolite（M4）of rhein was reported for the first time.The metabolism of anthraquinones occurred via hydroxylation,oxidation,methylation and deglycosylation.Efflux transporters were involved in the active transport of rhein that included P-gp,MRPs,and BCRP,of which BCRP played a major role in this process.The whole prescription,Rhubarb and Licorice water extract and Licorice water extract could decrease the absorption(P_{app AP-BL})but increase the secretion(P_{app BL-AP})of rhein.Meanwhile,the Licorice water extract could increase the secretion（transport）of rhein markedly（P<0.01）and reduce the ER as well,illustrating that the drug compatibility of Tiaowei-chengqi decoction could induce the absorption of rhein in Caco-2 cell model.Rhein had toxicity on HK-2 cells,including the inhibition of cell proliferation,cell shrinkage and vacuolation,increasing of LDH and NAG leakage,blocking the cell cycle and inducing apoptosis at different level.After accompanying rhein with the Licorice water extract,the toxic manifestation mentioned above were not altered at all,which implied the fact that the Licorice water extract were not be able to reduce toxicity by rhein on HK-2 cells,and the results provided evidence for the conclusion in the 4th chapter.This study aimed at the metabolism of anthraquinones of Rhubarb and used a Caco-2 cell monolayer model to explicate the possible compatibility mechanism of Tiaowei-chengqi decoction on the uptake and transport of rhein from the perspective of intestinal absorption.Besides,the study on comparing the toxicity between rhein and rhein accompanied by Licorice water extract on HK-2 cells was carried out,the results of which,of course,have laid a certain foundation for the pharmacodynamics study on Tiaowei-chengqi decoction as well as its clinical application.