title: Glucuronidation of bavachinin by human tissues and expressed UGT enzymes: Identification of UGT1A1 and UGT1A8 as the major contributing enzymes.
abstract: Bavachinin (BCI), a major bioactive compound in Chinese herbal Psoralea corylifolia, possesses a wide range of biological activities. In this study, the glucuronidation pathway of BCI was characterized for the first time, by using pooled human liver microsomes (HLM), pooled human intestine microsomes (HIM) and recombinant human UDP-glucosyltransferases (UGTs). One mono-glucuronide was detected in HLM in the presence of uridine-diphosphate glucuronic acid (UDPGA), and it was biosynthesized and well-characterized as BCI-4'-O-glucuronide (BCIG). Reaction phenotyping assay showed that UGT1A1, UGT1A3 and UGT1A8 were involved in BCI-4'-O-glucuronidation, while UGT1A1 and UGT1A8 displayed the higher catalytic ability among all tested UGT isoforms. Kinetic analysis demonstrated that BCI-4'-O-glucuronidation in both HLM and UGT1A1 followed sigmoidal kinetic behaviors and displayed much close Km values (12.4 μM in HLM & 9.7 μM in UGT1A1). Both chemical inhibition assays and correlation analysis demonstrated that UGT1A1 displayed a predominant role in BCI-4'-O-glucuronidation in HLM. Both HIM and UGT1A8 exhibited substrate inhibition at high concentrations, and Km values of HIM and UGT1A8 were 3.6 and 2.3 μM, respectively. Similar catalytic efficiencies were observed for HIM (199.3 μL/min/mg) and UGT1A8 (216.2 μL/min/mg). These findings suggested that UGT1A1 and UGT1A8 were the primary isoforms involved in BCI-4'-O-glucuronidation in HLM, and HIM, respectively.
authors: Department of Bioscience and Biotechnology, Dalian University of Technology, Dalian, China; Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
authors: Xia
authors: X
authors: Lv
authors: Dalian Medical University, Dalian, China.
authors: Jie
authors: J
authors: Hou
authors: Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
authors: Yang-Liu
authors: YL
authors: Xia
authors: Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Dalian Medical University, Dalian, China.
authors: Jing
authors: J
authors: Ning
authors: Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
authors: Gui-Yuan
authors: GY
authors: He
authors: Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
authors: Ping
authors: P
authors: Wang
authors: Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China. Electronic address: geguangbo@dicp.ac.cn.
authors: Guang-Bo
authors: GB
authors: Ge
authors: Department of Bioscience and Biotechnology, Dalian University of Technology, Dalian, China.
authors: Zhi-Long
authors: ZL
authors: Xiu
authors: Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China. Electronic address: ylingdicp@gmail.com.
authors: Ling
authors: L
authors: Yang
mesh_terms: D000818:Animals; D004958:Estradiol / Q000378:metabolism; D005419:Flavonoids / Q000493:pharmacokinetics*; D020719:Glucuronides / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D008861:Microsomes / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism; D014535:Uridine Diphosphate Glucuronic Acid / Q000378:metabolism; D000099148:UGT1A1 Enzyme; D047309:Flavones
chemical_list: D004958:Estradiol; D005419:Flavonoids; D020719:Glucuronides; D014453:Glucuronosyltransferase; D007527:Isoenzymes; D014535:Uridine Diphosphate Glucuronic Acid; D000099148:UGT1A1 Enzyme; C122075:UDP-glucuronosyltransferase, UGT1A3; C454320:UDP-glucuronosyltransferase, UGT1A8; C468752:bavachinin; D047309:Flavones
keywords: Bavachinin; Glucuronidation; Human tissues; UDP-glucuronosyltransferases; UGT1A1; UGT1A8