In vitroglucuronidation of Armillarisin A: UDP-glucuronosyltransferase 1A9 acts as a major contributor and significant species differences

Armillariella Oral Solution Ameliorates Small Intestinal Damage in a Mouse Model of Chemotherapy-Induced Mucositis

Background: Armillariella oral solution (AOS) shows therapeutic effect on gastrointestinal disorders. We aimed to investigate the potential efficacy of AOS on chemotherapy-induced intestinal mucositis in mice. Methods: Intestinal mucositis was induced in C57BL/6 mice by daily intraperitoneal injection of 5-FU (50 mg/kg) for 7 days. Effects of AOS (at 1, 5, and 10 mL/kg), or combined Bifidobacterium and Lactobacillus (CBL, 450 mg/kg) on the accompanying morphometry and histology, expression of Ki-67, caspase-3, Lgr5 and apoptosis of intestinal crypt cells were assessed. Results: Continuous administration of 5-FU to mice caused severe intestinal mucositis, which was histologically characterized by the destruction of intestinal crypts and shortening of villi, accompanied by diarrhea and body weight loss. Daily AOS administration dose-dependently reduced the severity of intestinal mucositis, diarrhea and body weight loss. Similar beneficial effects were observed with CBL. The expression of Ki-67 and Lgr5 decreased and the expression of caspase-3, and the number of apoptotic cells increased 24 h after the first 5-FU administration (P < 0.05), and these responses were significantly reduced by AOS treatment (P < 0.05, at 5 or 10 mL/kg). Conclusions: AOS can alleviate 5-FU-induced mucositis in mice via increasing Lgr5 expression and suppressing apoptotic responses in the intestinal crypt cells.

Identification of human UDP-glucuronosyltransferase isoforms involved in the isofraxidin glucuronidation and assessment of the species differences of the reaction

Isofraxidin, 7-Hydroxy-6.8-dimethoxy-2H-1-benzopyran-2-one, is a major active component of Acanthopanax senticosus, which has been used as Acanthopanax (Ciwujia) injection to treat cardiovascular and cerebrovascular diseases in China for more than thirty years. The purpose of this study was to identify the roles of human UDP-glucuronosyltransferases (UGTs) in isofraxidin glucuronidation in the liver and intestinal microsomes and to reveal the potential species differences by comparing the liver microsomal glucuronidation from different experimental animals. One metabolite was biosynthesized and characterized as isofraxidin-7-O-glucuronide by liquid chromatography tandem mass spectrometry (LC-MS/MS) and nuclear magnetic resonance (NMR). The intrinsic clearances in human liver and intestinal microsomes were 63.8 and 16.4μL/min/mg, respectively. Human liver microsomes displays higher potential for isofraxidin elimination than human intestinal microsomes. The reaction phenotyping analysis was conducted using cDNA-expressed human UGTs and chemical inhibitors. The results indicated that UGT1A1 and UGT1A9 were the main isoforms involved in the formation of isofraxidin-7-O-glucuronide. The isofraxidin glucuronidation in liver microsomes from human (HLM), rat (RLM), mouse (MLM), dog (DLM), monkey (CyLM), minipig (PLM), and guinea pig (GpLM) followed the Michealis-Menten model. The isofraxidin glucuronidation displays species differences in terms of catalytic activities. GpLM had the highest clearance with the CL_int value of 152μL/min/mg. CyLM, RLM and MLM exhibit similar catalytic activities in isofraxidin glucuronidation with the intrinsic clearance values of 54.6, 58.0 and 50.2μL/min/mg, respectively, which are higher than those of PLM and DLM (23.9 and 37.7μL/min/mg, respectively). Rat exhibits the most similar intrinsic metabolic clearance (CL_int) to human.