title: Comparison of proanthocyanidins in commercial antioxidants: grape seed and pine bark extracts.
abstract: The major constituents in grape seed and pine bark extracts are proanthocyanidins. To evaluate material available to consumers, select lots were analyzed using high-performance liquid chromatography, gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), gel permeation chromatography (GPC), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Atmospheric pressure chemical ionization (APCI) LC/MS was used to identify monomers, dimers, and trimers present. GC/MS analyses led to the identification of ethyl esters of hexadecanoic acid, linoleic acid, and oleic acid, as well as smaller phenolic and terpene components. The GPC molecular weight (MW) distribution indicated components ranging from approximately 162 to approximately 5500 MW (pine bark less than 1180 MW and grape seed approximately 1180 to approximately 5000 MW). MALDI-TOF MS analyses showed that pine bark did not contain oligomers with odd numbers of gallate units and grape seed contained oligomers with both odd and even numbers of gallate. Reflectron MALDI-TOF MS identified oligomers up to a pentamer and heptamer, and linear MALDI-TOF MS showed a mass range nearly double that of reflectron analyses.
authors.affiliation: Midwest Research Institute, 425 Volker Boulevard, Kansas City, Missouri 64110, USA.
authors.forename: Holly A
authors.initials: HA
authors.lastname: Weber
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Hodges
authors.forename: Jill R
authors.initials: JR
authors.lastname: Guthrie
authors.forename: Brandon M
authors.initials: BM
authors.lastname: O'Brien
authors.forename: David
authors.initials: D
authors.lastname: Robaugh
authors.forename: Alice P
authors.initials: AP
authors.lastname: Clark
authors.forename: Roger K
authors.initials: RK
authors.lastname: Harris
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Algaier
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Smith
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D056604:Grape Seed Extract; D013058:Mass Spectrometry; D028223:Pinus / Q000737:chemistry*; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000032:analysis* / Q000737:chemistry; D044945:Proanthocyanidins / Q000032:analysis*
chemical_list: D000975:Antioxidants; D056604:Grape Seed Extract; C511402:Grape Seed Proanthocyanidins; D010936:Plant Extracts; D044945:Proanthocyanidins