Liquid chromatography-tandem mass spectrometry analysis of oxidation of 2′-, 3′-, 4′- and 6-hydroxyflavanones by human cytochrome P450 enzymes
Creators: name: Shimada, Tsutomu
name: Nagayoshi, Haruna
name: Murayama, Norie
name: Takenaka, Shigeo
name: Katahira, Jun
name: Kim, Vitchan
name: Kim, Donghak
name: Komori, Masayuki
name: Yamazaki, Hiroshi
name: Guengerich, F. Peter
Publisher: name: Taylor & Francis
Year: 2020
Subjects: subject: Biochemistry
subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Ecology
subject: FOS: Biological sciences
subject: Sociology
subject: FOS: Sociology
subject: Marine Biology
subject: Inorganic Chemistry
subject: FOS: Chemical sciences
subject: Infectious Diseases
subject: FOS: Health sciences

description: 2′-Hydroxyflavanone (2′OHFva), 3′OHFva, 4′OHFva, and 6OHFva, the major oxidative products of flavanone by human cytochrome P450 (P450, CYP) enzymes, were studied in regard to further oxidation by human CYP1A1, 1A2, 1B1.1, 1B1.3, and 2A6. The products formed were analyzed with LC-MS/MS and characterized by their positive ion fragmentations on mass spectrometry.Several di-hydroxylated flavanone (diOHFva) and di-hydroxylated flavone (diOHFvo) products, detected by analyzing parent ions at <i>m/z</i> 257 and 255, respectively, were found following incubation of these four hydroxylated flavanones with P450s. The <i>m/z</i> 257 products were produced at higher levels than the latter with four substrates examined. The structures of the <i>m/z</i> 257 products were characterized by LC-MS/MS product ion spectra, and the results suggest that 3′OHFva and 4′OHFva are further oxidized mainly at B-ring by P450s while 6OHFva oxidation was at A-ring.Different diOHFvo products (<i>m/z</i> 255) were also characterized by LC-MS/MS, and the results suggested that most of these diOHFvo products were formed through oxidation or desaturation of the diOHFva products (<i>m/z</i> 257) by P450s. Only when 4′OHFva (<i>m/z</i> 241) was used as a substrate, formation of 4′OHFvo (<i>m/z</i> 239) was detected, indicating that diOHFvo might also be formed through oxidation of 4′OHFvo by P450s.Finally, our results indicated that CYP1 family enzymes were more active than CYP2A6 in catalyzing the oxidation of these four hydroxylated flavanones, and these findings were supported by molecular docking studies of these chemicals with active sites of P450 enzymes. 2′-Hydroxyflavanone (2′OHFva), 3′OHFva, 4′OHFva, and 6OHFva, the major oxidative products of flavanone by human cytochrome P450 (P450, CYP) enzymes, were studied in regard to further oxidation by human CYP1A1, 1A2, 1B1.1, 1B1.3, and 2A6. The products formed were analyzed with LC-MS/MS and characterized by their positive ion fragmentations on mass spectrometry. Several di-hydroxylated flavanone (diOHFva) and di-hydroxylated flavone (diOHFvo) products, detected by analyzing parent ions at <i>m/z</i> 257 and 255, respectively, were found following incubation of these four hydroxylated flavanones with P450s. The <i>m/z</i> 257 products were produced at higher levels than the latter with four substrates examined. The structures of the <i>m/z</i> 257 products were characterized by LC-MS/MS product ion spectra, and the results suggest that 3′OHFva and 4′OHFva are further oxidized mainly at B-ring by P450s while 6OHFva oxidation was at A-ring. Different diOHFvo products (<i>m/z</i> 255) were also characterized by LC-MS/MS, and the results suggested that most of these diOHFvo products were formed through oxidation or desaturation of the diOHFva products (<i>m/z</i> 257) by P450s. Only when 4′OHFva (<i>m/z</i> 241) was used as a substrate, formation of 4′OHFvo (<i>m/z</i> 239) was detected, indicating that diOHFvo might also be formed through oxidation of 4′OHFvo by P450s. Finally, our results indicated that CYP1 family enzymes were more active than CYP2A6 in catalyzing the oxidation of these four hydroxylated flavanones, and these findings were supported by molecular docking studies of these chemicals with active sites of P450 enzymes.