title: Enzymatic polymerization of dihydroquercetin using bilirubin oxidase.
abstract: Dihydroquercetin (or taxifolin) is one of the most famous flavonoids and is abundant in Siberian larch (Larix sibirica). The oxidative polymerization of dihydroquercetin (DHQ) using bilirubin oxidase as a biocatalyst was investigated and some physicochemical properties of the products were studied. DHQ oligomers (oligoDHQ) with molecular mass of 2800 and polydispersity of 8.6 were obtained by enzymatic reaction under optimal conditions. The oligomers appeared to be soluble in dimethylsulfoxide, dimethylformamide, and methanol. UV-visible spectra of oligoDHQ in dimethylsulfoxide indicated the presence of highly conjugated bonds. The synthesized oligoDHQ was also characterized by FTIR and (1)H and (13)C NMR spectroscopy. Comparison of NMR spectra of oligoDHQ with DHQ monomer and the parent flavonoids revealed irregular structure of a polymer formed via the enzymatic oxidation of DHQ followed by nonselective radical polymerization. As compared with the monomer, oligoDHQ demonstrated higher thermal stability and high antioxidant activity.
authors.affiliation: A. N. Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, 119071, Russia. yaropolov@inbi.ras.ru.
authors.forename: M E
authors.initials: ME
authors.lastname: Khlupova
authors.forename: I S
authors.initials: IS
authors.lastname: Vasil'eva
authors.forename: G P
authors.initials: GP
authors.lastname: Shumakovich
authors.forename: O V
authors.initials: OV
authors.lastname: Morozova
authors.forename: V A
authors.initials: VA
authors.lastname: Chertkov
authors.forename: A K
authors.initials: AK
authors.lastname: Shestakova
authors.forename: A V
authors.initials: AV
authors.lastname: Kisin
authors.forename: A I
authors.initials: AI
authors.lastname: Yaropolov
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000378:metabolism*; D058105:Polymerization; D011108:Polymers / Q000737:chemistry; D011794:Quercetin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
chemical_list: D000975:Antioxidants; D011108:Polymers; D011794:Quercetin; C003377:taxifolin; D044925:Oxidoreductases Acting on CH-CH Group Donors; C042401:bilirubin oxidase