The polyphenol constituents of grape pomace

Chemical investigation of Chardonnay grape pomace has resulted in the isolation of 17 polyphenols which were identified by NMR spectroscopy as gallic acid, its 3- and 4-β-glucopyranosides, trans-caftaric acid, cis- and trans-coutaric acid, 2-hydroxy-5-(2-hydroxyethyl)phenyl-β-glucopyranoside, catechin, epicatechin, procyanidin B1, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-galactoside, eucryphin, astilbin and engeletin. Gallic acid 3-β-glucopyranoside, gallic acid 4-β-glucopyranoside and 2-hydroxy-5-(2-hydroxyethyl)phenyl-β-glucopyranoside are reported here as natural grape constituents for the first time. ©