title: Biocatalytic synthesis of butein and sulfuretin by Aspergillus alliaceus.
abstract: Aspergillus alliaceus UI315 was examined for its potential to catalyze biotransformation reactions of chalcones that mimic plant biosynthetic processes. 3-(4' '-Hydroxyphenyl)-1-(2',4'-dihydroxyphenyl)propenone (4,2',4'-trihydroxychalcone, isoliquiritigein) (1) was efficiently transformed to two major metabolites that were isolated chromatographically and identified by spectroscopic methods as 3-(3' ',4' '-dihydroxyphenyl)-1-(2',4'-dihydroxyphenyl)propenone (butein) (7) and 2-[(3,4-dihydroxyphenyl)methylene]-6-hydroxy-3(2H)benzofuranone (7,3',4'-trihydroxyaurone, sulfuretin) (10). Inhibition experiments suggested that initial C-3 hydroxylation of 1 to 7 was catalyzed by a cytochrome P450 enzyme system. A second A. alliaceus enzyme, partially purified and identified as a catechol oxidase, catalyzed the oxidation of the catechol butein (7) likely through an ortho-quinone (8) that cyclized to the aurone product 10. This work showed that A. alliaceus UI315 contains oxidative enzyme systems capable of converting phenolic chalcones such as 1 into aurones such as 10 in a process that mimics plant biosynthetic pathways.
authors.affiliation: Division of Medicinal and Natural Products Chemistry, Center for Biocatalysis and Bioprocessing, College of Pharmacy, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Monica
authors.initials: M
authors.lastname: Sanchez-Gonzalez
authors.forename: John P N
authors.initials: JP
authors.lastname: Rosazza
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D001572:Benzofurans; D002599:Chalcone / Q000031:analogs & derivatives* / Q000378:metabolism; D047188:Chalcones; D002851:Chromatography, High Pressure Liquid; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000096:biosynthesis; D006900:Hydroxylation; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction
chemical_list: D001572:Benzofurans; D047188:Chalcones; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D005419:Flavonoids; C040918:butein; D002599:Chalcone; D003577:Cytochrome P-450 Enzyme System; C054989:sulfuretin