![Sample our Bioscience journals, sign in here to start your access, Latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5925/TOC-Subject-Sample-2021-Bioscience.jpg"})
Abstract
The effect of flavonoids on coumarin 7-hydroxylation, an activity marker of an important human liver cytochrome P450 isoform, cytochrome P450 2A6 (CYP2A6), was investigated in this study.
Coumarin 7-hydroxylase activity was measured fluorometrically in reaction mixtures containing cDNA-expressed CYP2A6, nicotinamide adenine dinucleotide phosphate generating system and 10 uM coumarin, at various concentrations of flavonoids.
Among the 23 compounds tested, most of the active members were from flavonol group of hydroxylated flavonoids, with myricetin being the most potent inhibitor followed by quercetin, galangin, and kaempferol.
Further exploration of the inhibition mechanism of these compounds revealed that myricetin, galangin, and kaempferol exhibited mixed-type of inhibition pattern while quercetin was observed to exhibit competitive mode of inhibition.
Structure-function analyses revealed that degree of inhibition was closely related to the number and location of hydroxyl groups, glycosylation of the free hydroxyl groups, degree of saturation of the flavane nucleus as well as the presence of the alkoxylated function.
Acknowledgements
We would like to express our thanks and gratitude to Professor John Miners (Flinders University, Adelaide, Australia) and Professor Donald Birkett (Johnson & Johnson Research Pty Ltd., Sydney, Australia) for their kind gifts of vectors pCWori+ and pACYC-OxR. This work was supported by the Science and Technology Research Grant from the Malaysia Toray Science Foundation (269817-K) as well as the International Medical University Research Fund (IMU 112/2006).
Declaration of interest
The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper.