豆奶甲醇提取物中抗氧化活性物质的鉴定

Identification of Antioxidants in Methanol Extracts from Soymilk

摘要:

本文主要在研究了豆奶甲醇提取物有无抗氧化活性的基础上，分析鉴定了其可能存在的抗氧化物质，为相关研究提供理论依据。测定抗氧化能力的方法包括1,1-二苯基-2-三硝基苯肼(1,1-Diphenyl-2-picrylhydrazyl radical, DPPH)法和铁离子还原能力(Ferric reducing antioxidant power ,FRAP)法。比色法测定总酚含量和总黄酮含量。通过超高效液相-四极杆飞行时间串联质谱(Ultra-high performance liquid chromatography-quadruple time-of-flight-mass spectrometry, UHPLC- QTOF-MS)测定豆奶甲醇提取液中活性成分的种类和含量。实验表明，豆奶甲醇提取液具有一定的抗氧化性，且DPPH法和FRAP 法测定豆奶抗氧化值不存在显著性差异。豆奶甲醇提取物的总酚含量(285.77±2.93 μg/mL)远高于总黄酮含量(11.27±0.51 μg/mL)。鉴定出5种化合物，其中只有6,7,4'-三羟基黄酮和Rha-Ara-GlcA-SoyB与抗氧化值存在正相关性。异黄素和大豆甙元两种异黄酮与抗氧化值存在着负相关，6,7,4'-三羟基黄酮可能是主要的抗氧化物质。

Abstract:

The paper mainly investigated the antioxidaative capacity of the soymilk methanol extracts and analyzed the possible existing antioxidants. DPPH (1,1-Diphenyl-2-picrylhydrazyl radical) method and FRAP (Ferric reducing antioxidant power ) method were used to analyze the antioxidative capacity of soymilk methanol extracts. The total contents of phenolics and total flavonoids were identified by colorimetric method.The kinds and contents of bioactivities of flavonoids were identified by ultra-high performance liquid chromatography-quadruple time-of-flight-mass spectrometry( UHPLC- QTOF-MS).The results showed that the methanol extracts of soymilk owned antioxidative activity. The antioxidative values showed no difference between DPPH and FRAP methods. Total phenolics content (285.77±2.93 μg/mL) was higher than total flavonoids content (11.27±0.51 μg/mL) in soymilk methanol extract. The compounds were identified and quantified by UHPLC- QTOF-MS.Among five bioactivities identified, 6,7,4'-Trihydroxyflavone and Rha-Ara-GlcA-SoyB showed positive correlation with their antioxidant values. However, genistein and daidzein perform negative correlation with antioxidant values. 6,7,4'-Trihydroxyflavone may be the main compound attributing to antioxidation of the commercial soymilk .