title: Isoquercitrin Esters with Mono- or Dicarboxylic Acids: Enzymatic Preparation and Properties.
abstract: A series of isoquercitrin (quercetin-3-O-β-d-glucopyranoside) esters with mono- or dicarboxylic acids was designed to modulate hydro- and lipophilicity and biological properties. Esterification of isoquercitrin was accomplished by direct chemoenzymatic reaction using Novozym 435 (lipase from Candida antarctica), which accepted C₅- to C12-dicarboxylic acids; the shorter ones, such as oxalic (C₂), malonic (C₃), succinic (C₄) and maleic (C₄) acids were not substrates of the lipase. Lipophilicity of monocarboxylic acid derivatives, measured as log P, increased with the chain length. Esters with glutaric and adipic acids exhibited hydrophilicity, and the dodecanedioic acid hemiester was more lipophilic. All derivatives were less able to reduce Folin-Ciocalteau reagent (FCR) and scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) than isoquercitrin; ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) radical-scavenging activity was comparable. Dodecanoate and palmitate were the least active in FCR and ABTS scavenging; dodecanoate and hemiglutarate were the strongest DPPH scavengers. In contrast, most derivatives were much better inhibitors of microsomal lipoperoxidation than isoquercitrin; butyrate and hexanoate were the most efficient. Anti-lipoperoxidant activity of monocarboxylic derivatives, except acetates, decreased with increasing aliphatic chain. The opposite trend was noted for dicarboxylic acid hemiesters, isoquercitrin hemidodecanedioate being the most active. Overall, IQ butyrate, hexanoate and hemidodecanedioate are the most promising candidates for further studies.
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, V&#237;deňsk&#225; 1083, CZ-142 20 Prague, Czech Republic. vavrikova@biomed.cas.cz.
authors.forename: Eva
authors.initials: E
authors.lastname: Vavříková
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, V&#237;deňsk&#225; 1083, CZ-142 20 Prague, Czech Republic. fanny.langschwager@uni-rostock.de.|Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, GE-18059 Rostock, Germany. fanny.langschwager@uni-rostock.de.
authors.forename: Fanny
authors.initials: F
authors.lastname: Langschwager
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, V&#237;deňsk&#225; 1083, CZ-142 20 Prague, Czech Republic. kalachova@gmail.com.
authors.forename: Lubica
authors.initials: L
authors.lastname: Jezova-Kalachova
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, V&#237;deňsk&#225; 1083, CZ-142 20 Prague, Czech Republic. alenka.petrickova@gmail.com.
authors.forename: Alena
authors.initials: A
authors.lastname: Křenková
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, V&#237;deňsk&#225; 1083, CZ-142 20 Prague, Czech Republic. baramiki@seznam.cz.
authors.forename: Barbora
authors.initials: B
authors.lastname: Mikulová
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, V&#237;deňsk&#225; 1083, CZ-142 20 Prague, Czech Republic. kuzma@biomed.cas.cz.
authors.forename: Marek
authors.initials: M
authors.lastname: Kuzma
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, V&#237;deňsk&#225; 1083, CZ-142 20 Prague, Czech Republic. kren@biomed.cas.cz.
authors.forename: Vladimír
authors.initials: V
authors.lastname: Křen
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, V&#237;deňsk&#225; 1083, CZ-142 20 Prague, Czech Republic. kata.valentova@email.cz.
authors.forename: Kateřina
authors.initials: K
authors.lastname: Valentová
mesh_terms: D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D003998:Dicarboxylic Acids / Q000737:chemistry; D004952:Esters / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D015394:Molecular Structure; D066244:Proton Magnetic Resonance Spectroscopy; D011794:Quercetin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D002264:Carboxylic Acids; D003998:Dicarboxylic Acids; D004952:Esters; C016527:isoquercitrin; D011794:Quercetin
keywords: DPPH; Novozym 435; antioxidant activity; fatty acid; isoquercitrin; lipase; lipoperoxidation; log P; quercetin