Chemical Synthesis of Hydroxycinnamic Acid Glucosides and Evaluation of Their Ability To Stabilize Natural Colors via Anthocyanin Copigmentation

Abstract

This work describes the chemical synthesis of O-aryl-beta-D-glucosides and 1-O-beta-D-glucosyl esters of hydroxycinnamic acids. In particular, O-aryl-beta-D-glucosides were efficiently prepared via a simple diastereoselective glycosylation procedure using phase transfer conditions. Despite the lability of its ester linkage, 1-O-beta-D-caffeoylglucose could also be obtained using a Lewis acid catalyzed glycosylation step and a set of protective groups that can be removed under neutral conditions. Hydroxycinnamic acid O-aryl-beta-D-glucosides were then quantitatively investigated for their affinity for the naturally occurring anthocyanin malvin (pigment). Formation of the pi-stacking molecular complexes (copigmentation) was characterized in terms of binding constants and enthalpy and entropy changes. The glucosyl moiety did not significantly alter these thermodynamic parameters, in line with a binding process solely involving the polyphenolic nuclei.

Fractionation and characterization of lignin-carbohydrate complexes (LCCs) of Eucalyptus globulus in residues left after MWL isolation. Part II: Analyses of xylan-lignin fraction (X-L)

“…Balakshin et al (2011) reported that phenyl glycosidestype LC linkages are present via carbohydrate signals C1-H1 around δ C / δ H 104 -99/4.8 -5.2 ppm according to model compound data of Terashima et al (1996) . The data of phenylpropanoid glucosides also support this expectation (Galland et al 2007 ;Mazur et al 2007 ). The correlations are observed at δ C / δ H 98.6/4.97 and 102.3/4.99 ppm in the spectrum of XL-F2, whereas the correlations are observed at δ C / δ H 99.5/5.11 and 102.3/4.77 ppm in the spectrum of LCC-AcOH.…”

Vinylcatechin Dimers Are Much Better Copigments for Anthocyanins than Catechin Dimer Procyanidin B3

“…Indeed, at pH 3.5, the flavylium ion of malvin (pK h =1.52 ( 0.02) (65) represents no more than ca. 1% of the total pigment concentration.…”

Vanillin formation from ferulic acid in Vanilla planifolia is catalysed by a single enzyme

“…4-β- D -glucopyranosylcoumaric acid: p- coumaric acid glucoside and ferulic acid glucoside were chemically synthesized according to Galland et al 59 and references therein.…”