Wang Xiaomin, Liu Rui, Yang Yukun, Zhang Min
Key Laboratory of Food Nutrition and Safety (Tianjin University of Science & Technology), Ministry of Education, Tianjin 300457, China.
Key Laboratory of Food Nutrition and Safety (Tianjin University of Science & Technology), Ministry of Education, Tianjin 300457, China.
Food Chem. 2015 Nov 15;187:37-43. doi: 10.1016/j.foodchem.2015.03.109. Epub 2015 Apr 2.
An aqueous aged garlic extract (AGE) was prepared by soaking sliced garlic in water for 20days at room temperature (23-25 °C). In order to locate the antioxidant ingredients of the aqueous AGE, an activity-guided fractionation approach using ABTS assay, DPPH assay and FRAP assay were conducted to guide the fractionation by means of extraction, column chromatography and semi-preparative HPLC. Some phenols and organosulfur compounds were identified as antioxidants in AGE by GC-MS. Furthermore, UV, IR, ESI-MS, NMR and specific rotation experiments led to the identification of l-phenylalanine, l-tryptophan, (3S)-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid, (1S,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid, and (1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid as the major antioxidants in the AGE. The EC50 values of these purified tetrahydro-β-carboline derivatives were 0.625-1.334 μmol/mL and 1.063-2.072 μmol/mL in ABTS assay and DPPH assay, respectively. It is the first time for us to identify (3S)-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid as an in vitro antioxidant in AGE.
通过在室温（23 - 25°C）下将切片大蒜在水中浸泡20天制备了水基陈化大蒜提取物（AGE）。为了确定水基AGE中的抗氧化成分，采用ABTS法、DPPH法和FRAP法进行活性导向分级分离，通过萃取、柱色谱和半制备HPLC来指导分级分离。通过GC - MS鉴定出一些酚类和有机硫化合物为AGE中的抗氧化剂。此外，紫外、红外、电喷雾质谱、核磁共振和旋光实验导致鉴定出L - 苯丙氨酸、L - 色氨酸、(3S)-1,2,3,4 - 四氢 - β - 咔啉 - 3 - 羧酸、(1S,3S)-1 - 甲基 - 1,2,3,4 - 四氢 - β - 咔啉 - 3 - 羧酸和(1R,3S)-1 - 甲基 - 1,2,3,4 - 四氢 - β - 咔啉 - 3 - 羧酸为AGE中的主要抗氧化剂。这些纯化的四氢 - β - 咔啉衍生物在ABTS法和DPPH法中的EC50值分别为0.625 - 1.334 μmol/mL和1.063 - 2.072 μmol/mL。这是我们首次鉴定出(3S)-1,2,3,4 - 四氢 - β - 咔啉 - 3 - 羧酸为AGE中的体外抗氧化剂。
