Premium
Reaction mechamism of oxidative rearrangement of flavanone in isoflavone biosynthesis
Author(s) -
Hashim Muhammed Faisal,
Hakamatsuka Takashi,
Ebizuka Yutaka,
Sankawa Ushio
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80410-k
Subject(s) - liquiritigenin , chemistry , flavanone , daidzein , hydroxylation , monooxygenase , microsome , stereochemistry , enzyme , biochemistry , cytochrome p450 , flavonoid , genistein , antioxidant , medicine , alternative medicine , pathology
Microsomes that were prepared from elicitor‐treated Pueraria lobata cell cultures catalyzed the conversion of liquiritigenin, a flavanone, into daidzein, an isoflavone. The reaction was resolved into two steps. 2, 7, 4'‐Trihydroxyisoflavanone was formed as a major product when liquiritigenin was incubated with carefully washed microsomes in the presence of NADPH. The structure of 2, 7, 4'‐trihydroxyisoflavanone was confirmed by mass and 1 H NMR spectroscopies. The enzyme responsible for this rearrangement reaction is a cytochrome P‐450‐dependent monooxygenase. Upon treatment with a soluble enzyme fraction 2, 7, 4'‐trihydroxyisoflavone yielded daidzein quantitatively. The incorporation of 18 O from 18 O 2 into the 2‐hydroxy group of 2, 7, 4'‐trihydroxyisoflavanone was demonstrated by the shift of molecular ion in its mass spectrum. Based on these observations a new reaction mechanism, hydroxylation associated with 1,2‐migration, is proposed for the oxidative rearrangement reaction catalyzed by the cytochrome P‐450 enzyme of Pueraria lobata .