title: Identification and characterization of human UDP-glucuronosyltransferases responsible for the in vitro glucuronidation of salvianolic acid A.
abstract: Glucuronidation is an important pathway in the elimination of salvianolic acid A (Sal A); however the mechanism of UDP-glucuronosyltransferases (UGTs) in this process remains to be investigated. In this study, the kinetics of Sal A glucuronidation by pooled human liver microsomes (HLMs), pooled human intestinal microsomes (HIMs) and 12 recombinant UGT isozymes were investigated. The glucuronidation of Sal A can be shown both in HLMs and HIMs with K(m) values of 39.84 ± 3.76 and 54.04 ± 4.36 µM, respectively. Among the 12 human UGTs investigated, UGT1A1 and UGT1A9 were the major isoforms that catalyzed the glucuronidation of Sal A (K(m) values of 29.72 ± 2.20 and 24.40 ± 2.60 µM). UGT1A9 showed the highest affinity of Sal A glucuronidation. Furthermore, a significant correlation between Sal A glucuronidation and propofol glucuronidation (a typical UGT1A9 substrate) was observed. The chemical inhibition study showed that the IC(50) for phenylbutazone inhibition of Sal A glucuronidation was 50.3 ± 4.3 and 39.4 ± 2.9 µM by HLMs and UGT1A9, respectively. Mefenamic acid inhibited Sal A glucuronidation in UGT1A1 and HLMs with IC(50) values of >200 and 12.4 ± 2.2 µM, respectively.
authors.affiliation: State Key Laboratory of Natural Products and Functions, Ministry of Education, China Pharmaceutical University, Nanjing, P.R. China.
authors.forename: De-en
authors.initials: DE
authors.lastname: Han
authors.forename: Yi
authors.initials: Y
authors.lastname: Zheng
authors.forename: Xijing
authors.initials: X
authors.lastname: Chen
authors.forename: Jiake
authors.initials: J
authors.lastname: He
authors.forename: Di
authors.initials: D
authors.lastname: Zhao
authors.forename: Shuoye
authors.initials: S
authors.lastname: Yang
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Zhang
authors.forename: Zhonglin
authors.initials: Z
authors.lastname: Yang
mesh_terms: D002109:Caffeic Acids / Q000378:metabolism / Q000493:pharmacokinetics*; D005966:Glucuronidase / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis / Q000187:drug effects; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects / Q000201:enzymology; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D007773:Lactates / Q000378:metabolism / Q000493:pharmacokinetics*; D008528:Mefenamic Acid / Q000494:pharmacology; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D015742:Propofol / Q000378:metabolism / Q000493:pharmacokinetics; D013223:Statistics as Topic; D000090264:UDP-Glucuronosyltransferase 1A9; D000099148:UGT1A1 Enzyme
chemical_list: D002109:Caffeic Acids; D005966:Glucuronidase; D014453:Glucuronosyltransferase; D007527:Isoenzymes; D007773:Lactates; D008528:Mefenamic Acid; D015742:Propofol; D000090264:UDP-Glucuronosyltransferase 1A9; D000099148:UGT1A1 Enzyme; C000715591:UGT1A9 protein, human; C066201:salvianolic acid A