Identification of Antioxidants in Aged Garlic Extract by Gas Chromatography-Mass Spectrometry and Liquid Chromatography-Mass Spectrometry

Abstract

A novel aged garlic extract, with high antioxidant activities, was prepared by soaking sliced garlic in 10% ethanol solution for 90 days. In order to locate the antioxidant ingredients of aged garlic extract, 2,2-azinobis-6-s (3-ethylbenzothiazoline sulfonic acid) assay, hydroxyl free radical assay, 2,2-diphenyl-1-picrylhydrazyl assay, and ferric reducing/antioxidant power assay were conducted to guide the fractionation of aged garlic extract by means of extraction. As a result, the ethyl acetate fraction was identified as the highest antioxidant activity in aged garlic extract. Therefore, the ingredient information of the ethyl acetate fraction were obtained through gas chromatography-mass spectrometry and ultra performance liquid chromatography mass spectrometry / mass spectrometry analysis. Some phenols and diallyl disulphide, 5-(hydroxymethyl)-2-furancarboxaldehyde, S-allyl-cysteine, S-allyl-mercaptocysteine, and 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid were identified as potent antioxidants in aged garlic extract by gas chromatography-mass spectrometry and ultra performance liquid chromatography mass spectrometry / mass spectrometry, respectively. The biological activities and formation mechanisms of these identified compounds were discussed.