title: Biological Synthesis of Baicalein Derivatives UsingEscherichia coli.
abstract: Two baicalein derivatives, baicalin and oroxylin A, were synthesized in this study. These derivatives exhibit diverse biological activities, such as anxiolytic and anticancer activities as well as memory enhancement. In order to synthesize baicalin from aglycon baicalein usingEscherichia coli, we utilized a glycosyltransferase that regioselectively transfers glucuronic acid from UDP-glucuronic acid to the 7-hydroxy group of baicalein. To increase baicalin productivity, anaraAdeletionE. colimutant, which accumulates UDP-glucuronic acid, was used, andugd, which converts UDP-glucose to UDP-glucuronic acid, was overexpressed. Using these strategies, approximately 720.3 µM baicalin was synthesized from 1,000 µM baicalein. Oroxylin A was then synthesized from baicalein. TwoO-methyltransferases (OMTs), ROMT-15 and POMT-9, were tested to examine the production of oroxylin A from baicalein.E. coliharboringROMT-15andE. coliharboringPOMT-9produced reaction products that had different retention times, indicating that they are methylated at different positions; the structure of the reaction product from POMT-9 was consistent with oroxylin A, whereas that from ROMT-15 was 7-O-methyl baicalein. UsingE. coliharboringPOMT-9, approximately 50.3 mg/l of oroxylin A (177 µM) was synthesized from 54 mg/l baicalein (200 µM).
authors.affiliation: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul 05029, Republic of Korea.
authors.forename: Da Hye
authors.initials: DH
authors.lastname: Han
authors.affiliation: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul 05029, Republic of Korea.
authors.forename: Youngshim
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul 05029, Republic of Korea.
authors.forename: Joong-Hoon
authors.initials: JH
authors.lastname: Ahn
mesh_terms: D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D044950:Flavanones / Q000096:biosynthesis* / Q000737:chemistry; D005419:Flavonoids / Q000378:metabolism; D020723:Glucuronic Acid / Q000378:metabolism; D016695:Glycosyltransferases / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D044950:Flavanones; D005419:Flavonoids; C038044:baicalin; C006680:baicalein; D020723:Glucuronic Acid; D016695:Glycosyltransferases
keywords: Baicalein; baicalin; biotransformation; oroxylin A