%0 Journal Article %A Kayoko Shimoi %A Noriko Saka %A Ryushi Nozawa %A Motoyoshi Sato %A Izumi Amano %A Tsutomu Nakayama %A Naohide Kinae %T Deglucuronidation of a Flavonoid, Luteolin Monoglucuronide, during Inflammation %D 2001 %J Drug Metabolism and Disposition %P 1521-1524 %V 29 %N 12 %X In this study, we investigated whether luteolin monoglucuronide was converted to free aglycone during inflammation using human neutrophils stimulated with ionomycin/cytochalasin B and rats treated with lipopolysaccharide (LPS). β-Glucuronidase activity was assayed using 4-methylumbelliferyl-glucuronide and methanol extracts of rat plasma containing luteolin monoglucuronide. The released 4-methylumbelliferone, a fluorescent molecule, was quantified by fluorometry. Deglucuronidation of luteolin monoglucuronide was examined by high-performance liquid chromatography (HPLC) analysis. HPLC analyses showed that the supernatants obtained from neutrophils stimulated with ionomycin/cytochalasin B hydrolyzed luteolin monoglucuronide to free luteolin. β-Glucuronidase activity in human serum from patients on hemodialysis increased significantly compared with that from healthy volunteers. The β-glucuronidase activity in rat plasma increased after i.v. injection of LPS. The ratio of luteolin to luteolin monoglucuronide in plasma of LPS-treated rats also increased. These results suggest that during inflammation β-glucuronidase is released from stimulated neutrophils or certain injured cells and then deglucuronidation of flavonoids occurs. The American Society for Pharmacology and Experimental Therapeutics %U https://dmd.aspetjournals.org/content/dmd/29/12/1521.full.pdf