title: In vitro activity-guided identification of antioxidants in aged garlic extract.
abstract: Activity-guided fractionation was applied on an aged garlic extract (AGE), reported to show strong antioxidant activity, in order to locate the key in vitro antioxidant ingredients by means of the hydrogen peroxide scavenging (HPS) assay as well as the ORAC assay. Besides the previously reported four tetrahydro-β-carbolines, (1R,3S)- and (1S,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid and (1R,3S)- and (1S,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-1,3-dicarboxylic acid, LC-MS/MS, LC-TOF-MS, and 1D/2D-NMR experiments led to the identification of coniferyl alcohol and its dilignols (-)-(2R,3S)-dihydrodehydrodiconiferyl alcohol, (+)-(2S,3R)-dehydrodiconiferyl alcohol, erythro-guaiacylglycerol-β-O-4'-coniferyl ether, and threo-guaiacylglycerol-β-O-4'-coniferyl ether as the major antioxidants in AGE. The purified individual compounds showed high antioxidant activity, with EC50 values of 9.7-11.8 μM (HPS assay) and 2.60-3.65 μmol TE/μmol (ORAC assay), respectively.
authors: Technische Universität München , Lise-Meitner Strasse 34, D-85354 Freising, Germany.
authors: Toshiaki
authors: T
authors: Matsutomo
authors: Timo D
authors: TD
authors: Stark
authors: Thomas
authors: T
authors: Hofmann
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry*; D005591:Chemical Fractionation; D002851:Chromatography, High Pressure Liquid; D005609:Free Radicals / Q000737:chemistry; D005737:Garlic / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010636:Phenols / Q000032:analysis / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D013997:Time Factors
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D010636:Phenols; D010936:Plant Extracts; D006861:Hydrogen Peroxide; C010559:coniferyl alcohol