Published: August 03, 2011 r2011 American Chemical Society 9512 dx.doi.org/10.1021/jf2015039 | J. Agric. Food Chem. 2011, 59, 9512–9522 ARTICLE pubs.acs.org/JAFC Identification of (Poly)phenolic Compounds in Concord Grape Juice and Their Metabolites in Human Plasma and Urine after Juice Consumption Angelique Stalmach, † Christine A. Edwards, ‡ JoLynne D. Wightman, § and Alan Crozier* ,† † Joseph Black Building, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 888, United Kingdom ‡ School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Yorkhill Hospital, Glasgow G3 8SJ, United Kingdom § Welch Foods Inc., Concord, Massachusetts 01742, United States ABSTRACT: Analysis of Concord grape juice by HPLC with ESI-MS n , PDA, and fluorescence detection resulted in the identification and quantification of 60 flavonoids and related phenolic compounds, which were present at an overall concentration of 1508 ( 31 μmol/L. A total of 25 anthocyanins were detected, which were mono- and di-O-glucosides, O-acetylglucosides, O-p- coumaroyl-O-diglucosides, and O-p-coumaroylglucosides of delphinidin, cyanidin, petunidin, peonidin, and malvidin. The anthocyanins represented 46% of the total phenolic content of the juice (680 μmol/L). Tartaric esters of hydroxycinnamic acids, namely, trans-caftaric and trans-coutaric acids, and to a lesser extent trans-fertaric acid accounted for 29% of the phenolic content, with a total concentration of 444 μmol/L, of which 85% comprised trans-caftaric acid. Free hydroxycinnamic acids were also quantified but contributed to <1% of the total phenolic content (8.4 μmol/L). The other groups of polyphenolic compounds present in the juice, accounting for 24% of the total, comprised monomeric and oligomeric units of (epi)catechin and (epi)gallocatechin (248 μmol/L), flavonols (76 μmol/L), gallic acid (51 μmol/L), and trans-resveratrol (1.5 μmol/L). The bioavailability of the (poly)phenolic compounds in 350 mL of juice was investigated following acute intake by healthy volunteers. Plasma and urine were collected over 024 h and analyzed for parent compounds and metabolites. In total, 41 compounds, principally metabolites, were identified. KEYWORDS: Vitis labrusca, Concord purple grape juice, (poly)phenolic constituents, acute ingestion, human plasma and urinary metabolites ’ INTRODUCTION Concord grapes belong to the Vitis labrusca vines, which are cultivated principally in North America. Concord grapes were developed by Ephraim Wales Bull in 1849, near the Massachu- setts village of Concord. They are used to produce an unfer- mented grape juice, which was originally processed by Dr. Welch and used for communion in local churches. 1 The juice is produced through the hot press method, which involves adding a pectolytic enzyme and heating the crushed grapes, which enhances the extraction of color from the skins into the juice. 2 Successive pasteurizations also ensure the inactivation of yeasts, preventing fermentation of sugars in the grape. Concord grape juice contains high levels of antioxidants compared to many other commercial fruit juices and drinks, probably as a consequence of the juice containing high con- centrations of an unusual combination of anthocyanins, tarta- rate esters of hydroxycinnamates, and flavan-3-ols. 3 There is also evidence that consumption of Concord grape juice can have potential protective effects on health. Consumption of 510 mL/kg body weight of purple grape juice by healthy volunteers for 714 days resulted in an improvement in blood vessel endothelial function by increased platelet-derived nitric oxide (NO) production, 4 reduced platelet aggregation, 5 im- proved flow-mediated dilation, 6 decreased LDL oxidation, 7 and potentially reduced risk of cardiovascular events. When con- sumed for 68 weeks Concord grape juice has been shown to induce improved cognitive function in aged rats. 8 Improved memory function was demonstrated in a recent study in older adult humans with memory decline, but not dementia, who consumed Concord grape juice at a daily dose of 69 mL/kg body weight for 12 weeks. 9 The aim of the current study was to apply HPLC-MS n methodology to generate a more detailed profile of the poly- phenolic and phenolic constituents of Concord grape juice and to gain information on the bioavailability and metabolic fate of these compounds by measuring the parent compounds and their metabolites in plasma and urine after acute consumption of 350 mL of juice by healthy human volunteers. ’ MATERIALS AND METHODS Chemicals. Procyanidins B1 and B2, p-coumaric acid, ethyl gallate, 3-(3 0 -hydroxyphenyl)propionic acid (dihydrocoumaric acid), and Received: April 14, 2011 Revised: July 28, 2011 Accepted: August 3, 2011