7219-89-8Relevant academic research and scientific papers
Regiospecificity and stereospecificity of human udpglucuronosyltransferases in the glucuronidation of estriol, 16-epiestriol, 17-epiestriol, and 13-epiestradiols
Sneitz, Nina,Vahermo, Mikko,Mosorin, Johanna,Laakkonen, Liisa,Poirier, Donald,Finel, Moshe
, p. 582 - 591 (2013/04/10)
The glucuronidation of estriol, 16-epiestriol, and 17-epiestriol by the human UDP-glucuronosyltransferases (UGTs) of subfamilies 1A, 2A, and 2B was examined. UGT1A10 is highly active in the conjugation of the 3-OH in all these estriols, whereas UGT2B7 is the most active UGT toward one of the ring D hydroxyls, the 16-OH in estriol and 16-epiestriol, but the 17-OH in 17-epiestriol. Kinetic analyses indicated that the 17-OH configuration plays a major role in the affinity of UGT2B7 for estrogens. The glucuronidation of the different estriols by the human liver and intestine microsomes reflects the activity of UGT1A10 and UGT2B7 in combination with the tissues' difference in UGT1A10 expression. The UGT1A10 mutant 1A10-F93G exhibited much higher Vmax values than UGT1A10 in estriol and 17-epiestriol glucuronidation, but a significantly lower value in 16-epiestriol glucuronidation. To this study on estriol glucuronidation we have added experiments with 13-epiestradiol, a synthetic estradiol in which the spatial arrangement of the methyl on C18 and the hydroxyl on C17 is significantly different than in other estrogens. In comparison with estradiol glucuronidation, the C13 configuration change decreases the turnover of UGTs that conjugate the 3-OH, but increases it in UGTs that primarily conjugate the 17-OH. Unexpectedly, UGT2B17 exhibited similar conjugation rates of both the 17-OH and 3-OH of 13-espiestradiol. The combined results reveal the strong preference of UGT1A10 for the 3-OH of physiologic estrogens and the equivalently strong preference of UGT2B7 and UGT2B17 for the hydroxyls on ring D of such steroid hormones. Copyright
Eudismic analysis of tricyclic sesquiterpenoid alcohols: Lead structures for the design of potent inhibitors of the human UDP-glucuronosyltransferase 2B7
Bichlmaier, Ingo,Kurkela, Mika,Siiskonen, Antti,Finel, Moshe,Yli-Kauhaluoma, Jari
, p. 386 - 400 (2008/03/27)
The epimeric tricyclic sesquiterpenoid alcohols globulol, epiglobulol, cedrol, epicedrol, longifolol, and isolongifolol were investigated in their ability to inhibit the recombinant human UDP-glucuronosyltransferase (UGT) 2B7. The stereoisomers displayed rapidly reversible competitive inhibition, which was substrate-independent. Longifolol and its stereoisomer isolongifolol displayed the lowest competitive inhibition constants (Kic) of 23 and 26 nM, respectively. The Kic values of cedrol and its epimer epicedrol were 0.15 and 0.21 μM, those of globulol and epiglobulol were 5.4 and 4.0 μM, respectively. The diastereomeric alcohols exhibited nearly identical affinities toward UGT2B7 indicating that the spatial arrangement of the hydroxy group had no influence on the dissociation of the enzyme-terpenoid complex. The high affinities stemmed presumably from mere hydrophobic interactions between the hydrocarbon scaffold of the terpenoid alcohol and the binding site of the enzyme. Glucuronidation assays revealed that there were large differences in the rates at which the epimeric alcohols were conjugated. Therefore, the spatial arrangement of the hydroxy group controlled the rate of the UGT2B7-catalyzed reaction. The introduction of a methyl group into the side chain of isolongifolol and longifolol increased the steric hindrance. As a result, the rate of the UGT2B7-catalyzed reaction was decreased by more than 88%. The findings indicated that the rate of the UGT2B7-catalyzed glucuronidation is significantly controlled by stereochemical and steric factors. Considering the high inhibition levels exerted by the tricyclic sesquiterpenoid alcohols, these compounds might serve as valuable lead structures for the design of potent inhibitors for UGT2B7.
The synthesis of estriol 16- and 17-monoglucuronide from estriol
Wu, Yinqiu,Blackwell, Leonard F.
, p. 452 - 456 (2007/10/02)
An efficient and convenient procedure for the synthesis of estriol 16- and 17-monoglucuronides from estriol is described. This is achieved by the selective protection and deprotection of the hydroxy groups in estriol, Koenigs-Knorr reactions with methyl 1-bromo-1-deoxy-2,3,4-tri-O-acetyl-α-D-glucopyranuronate and subsequent hydrolysis. The products have been characterized by proton nuclear magnetic resonance (1H NMR), two-dimensional 1H homonuclear shift-correlated spectra (2D-COSY) and mass spectra. The selective Koenigs-Knorr reaction of the alcoholic hydroxyl group in the presence of a phenolic hydroxyl group is also reported. Keywords: steroids; estriol; estriol 16- and 17-glucuronides; selective protection; Koenigs-Knorr reaction; synthesis.
