Photochemistry of 3- and 4-nitrophenyl azide: detection and characterization of reactive intermediates

1987 ◽  
Vol 109 (25) ◽  
pp. 7803-7810 ◽  
Author(s):  
Tsuei Yun Liang ◽  
Gary B. Schuster
Keyword(s):  
Reactive Intermediates

Photochemical Characterization of Paddy Water during Rice Cultivation: Formation of Reactive Intermediates for As(III) Oxidation

2021 ◽  
pp. 117721
Author(s):  
Yu Zeng ◽  
Guodong Fang ◽  
Qinglong Fu ◽  
Dionysios D. Dionysiou ◽  
Xiaolei Wang ◽  
...  
Keyword(s):  
Reactive Intermediates ◽  
Rice Cultivation ◽  
Paddy Water

Oxypeucedanin is a mechanism-based inactivator of CYP2B6 and CYP2D6

2021 ◽  
Vol 22 ◽  
Author(s):  
Kehan Zhang ◽  
Yilin Li ◽  
Yao Fu ◽  
Tiantian Cui ◽  
Qian Wang ◽  
...  
Keyword(s):  
Pain Relief ◽  
Liver Microsomes ◽  
Reactive Intermediates ◽  
Enzyme Inactivation ◽  
Time Dependent ◽  
Reactive Metabolites ◽  
Angelica Dahurica ◽  
Dependent Inhibition ◽  
Microsomal Incubation

Background: Herbal medicine Angelica dahurica is widely employed for the treatment of rheumatism and pain relief in China. Oxypeucedanin is a major component of the herb. Objectives : The objectives of this study are aimed at the investigation of mechanism-based inactivation of CYP2B6 and CYP2D6 by oxypeucedanin, characterization of the reactive metabolites associated with the enzyme inactivation, and identification of the P450s participating in the bioactivation of oxypeucedanin. Methods : Oxypeucedanin was incubated with liver microsomes or recombinant CYPs2B6 and 2D6 under designed conditions, and the enzyme activities were measured by monitoring the generation of the corresponding products. The resulting reactive intermediates were trapped with GSH and analyzed by LC-MS/MS. Results : Microsomal incubation with oxypeucedanin induced a time-, concentration-, and NADPH-dependent inhibition of CYPs2B6 and 2D6 with kinetic values of KI/kinact 1.82 µM/0.07 min-1 (CYP2B6) and 8.47 µM/0.044 min-1 (CYP2D6), respectively. Ticlopidine and quinidine attenuated the observed time-dependent enzyme inhibitions. An epoxide and/or γ-ketoenal intermediate(s) derived from oxypeucedanin was/were trapped in microsomal incubations. CYP3A4 was the primary enzyme involved in the bioactivation of oxypeucedanin. Conclusion : Oxypeucedanin was a mechanism-based inactivator of CYP2B6 and CYP2D6. An epoxide and/or γ-ketoenal intermediate(s) may be responsible for the inactivation of the two enzymes.

Sign in / Sign up

Export Citation Format

Share Document