The Study Of Lead Compounds Based On Celastrol Metabolism In The Gastric

Celastrol,a triterpenoid isolated from the roots of Tripterygium wilfordii Hook.f.,was reported to possess anticancer,anti-inflammatory,immunity suppression,and anti-neurodegenerative activities.Previous study revealed that oral administration of celastrol showed significantly lower acute toxicity than that of intraperitoneal injection,though their anticancer of the two ways in vivo were comparable.In this thesis,the metabolites of celastrol in gastric juice were studied to discover new lead compounds with potency and lower toxicity.The druggability of the metabolites was investigated as well.In the first part,previous researches on celastrol were reviewed.In the second part,metabolism of celastrol in gastric juice was studied by establishing animal model of gastric metabolism.An HPLC method was developed to determinate the variation of celastrol after oral administration,and to accurately quantify the metabolite of celastrol in vivo.The polarity of the metabolism of celastrol was higher than celastrol.The results of this work paved the way for further investigation on the metabolism of celastrol after oral administration.In the third part,a method aiming at collecting celastrol metabolite in large scale was developed by simulating the acid environment of stomach.The HPLC analysis revealed that the main metabolite of celastrol in vitro was the same as that obtained in vivo.The metabolite of celastrol in vitro was prepared by chromatography,and its structure was identified by spectropic methods inclufing 1H-NMR,13C-NMR,ESI-MS,and IR.In the fourth part,cytotoxic activity of the metabolite was evaluated against Bel-7402,HepG2,H460,HUVEC,RKO-E6,RKO,and SW620 cell lines.Cell viability was measured by the MTT method and IC50 values were calculated.The cytotoxic activities of the metabolite against these cancer cell lines were less potent than celastrol.In the fifth part,the acute toxicity of the metabolite was studied.Response and mortality were observed of on mouse by peritoneal injection of the metabolite.The safe dose of metabolite was higher than celastrol,and its LD50 was 50 fold of celastrol.The disadvantage of the high toxicity was overcome.