title: Efficient one pot extraction and depolymerization of grape (Vitis vinifera) pomace procyanidins for the preparation of antioxidant thio-conjugates.
abstract: Antioxidant thio-conjugates were obtained from white grape pomace by a clean and efficient one pot extraction and depolymerization method using water and cysteamine hydrochloride. To evaluate the potential of grape pomaces of different origins as sources of proanthocyanidins and conjugates, we conducted varietal comparative studies of polyphenol content, antioxidant power, and procyanidin composition. Xarel.lo proved to be the richest source of polyphenols. The total conversion into the conjugates was as high as 8 g/kg of Xarel.lo grape pomace, with a 50-fold excess of cysteamine, and 3 g/kg, with a 5-fold excess of cysteamine. After purification by preparative cation exchange and reversed phase high-performance liquid chromatography, 17 g of 63% pure 4beta-(2-aminoethylthio)epicatechin (acetate salt) was obtained from 35 kg of moist pomace. The procedure described here will make the antioxidant thio-derivatives efficiently available directly from raw plant byproducts such as grape pomace.
authors.affiliation: Institute for Chemical and Environmental Research (IIQAB-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain.
authors.forename: Ariadna
authors.initials: A
authors.lastname: Selga
authors.forename: Xavier
authors.initials: X
authors.lastname: Sort
authors.forename: Raül
authors.initials: R
authors.lastname: Bobet
authors.forename: Josep Lluís
authors.initials: JL
authors.lastname: Torres
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D044946:Biflavonoids; D002392:Catechin / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003543:Cysteamine; D005419:Flavonoids / Q000032:analysis / Q000302:isolation & purification; D005638:Fruit / Q000737:chemistry*; D010636:Phenols / Q000032:analysis / Q000302:isolation & purification; D010936:Plant Extracts / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D059808:Polyphenols; D044945:Proanthocyanidins; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D027843:Vitis / Q000737:chemistry*; D014867:Water
chemical_list: D000975:Antioxidants; D044946:Biflavonoids; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D011108:Polymers; D059808:Polyphenols; D044945:Proanthocyanidins; D013438:Sulfhydryl Compounds; D014867:Water; C017674:procyanidin; D003543:Cysteamine; D002392:Catechin