Enzymatic acylation of flavonoids by Candida antarctica and Pseudomonas cepacia lipases : kinetic, structural and conformationnal studies

This work aims to study the performances and the regioselcetivity of two lipases throughout the acylation of flavonoids in organic medium. This study showed that the solubility in acetonitrile, acetone and tert-amyl alcohol depends on the nature of the flavonoid. The highest solubility, in actonitri...

Full description

Bibliographic Details
Main Author: Chebil, Latifa
Other Authors: Institut National Polytechnique de Lorraine (INPL), Institut National Polytechnique de Lorraine, Mohamed Ghoul, Christine Gerardin
Format: Doctoral or Postdoctoral Thesis
Language:French
Published: HAL CCSD 2006
Subjects:
flanonoids
acylation
CAL-B
PSL-C
solubility
structure
anti-radical activity
molecular modeling
Flavonoïdes
Solubilité
Activité anti-radicalaire
Modélisation moléculaire
Lipases
Cinétique chimique
Molécules -Modèles mathématiques
[SDV.AEN]Life Sciences [q-bio]/Food and Nutrition
[SDV.BIO]Life Sciences [q-bio]/Biotechnology
Antarc*
Antarctica
Online Access:https://hal.univ-lorraine.fr/tel-01752787
https://hal.univ-lorraine.fr/tel-01752787/document
https://hal.univ-lorraine.fr/tel-01752787/file/2006_CHEBIL_L.pdf
Description
Summary:This work aims to study the performances and the regioselcetivity of two lipases throughout the acylation of flavonoids in organic medium. This study showed that the solubility in acetonitrile, acetone and tert-amyl alcohol depends on the nature of the flavonoid. The highest solubility, in actonitrile, was obtained with the naringenin and hesperitin and the lowest with rutin and isoquercitrin. The thermophysical properties are also affected by the nature of flavonoids. Thus glycosylated flavonoids are characterized by a low melting point and a high enthalpy of fusion compared to the aglycon ones. From the kinetic acylation data, the highest conversion yields of 99% were obtained with quercetin. These conversion yields vary according to the nature of the flavonoid and the acyl donor, the molar ratio (vinyl acetate/flavonoid) and the nature of the solvent. The lowest conversion yield was obtained with hesperitin. Molecular modeling of flavonoids in vacuum and solvents allows to study the role of conformation structure on solubility and to release the structure-activity relationship with many electronic descriptors. Finally, OPLS all atoms were built to study, by molecular dynamics, quercetin in condensed phases of organic solvents. Ce travail a pour objectif d'étudier les perfomances et la régiosélectivité de deux lipases lors de l'acylation de flavonoïdes en milieu organique. Cette étude a permis de montrer que la solubilité dans l'acétonitrile, l'acétone et le tert-amyl alcool dépend de la nature du flavonoïde. La solubilité la plus élevée a été obtenue avec la naringénine et l'hepéritine et la plus faible pour la rutine et l'isoquercitrine. Les propriétés thermophysiques sont également affectées par la nature du flavonoïde. Ainsi, les flavonoïdes glycosylés possèdent un point de fusion moins élevé et une enthalpie de fusion plus élevée que ceux des aglycones. Du point de vue cinétique d'acylation, des rendements de conversion de 99% ont été obtenus avec la quercétine. Ces rendements varient en fonction de la ...

Similar Items