青钱柳叶活性成分的抗氧化活性及UPLC-QTOF-MS/MS分析

摘要

利用96孔板法测定青钱柳叶不同溶剂(水、70％乙醇、乙酸乙酯和正己烷)提取物中总酚、总黄酮含量及抗氧化活性(DPPH自由基清除能力、还原能力、总抗氧化能力),考察酚类物质含量与抗氧化活性的相关性,并采用超高效液相色谱-四极杆飞行时间串联质谱(ultra performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spetrometry,UPLC-QTOF-MS/MS)分析提取物中主要活性成分.结果表明:不同提取物中总酚、总黄酮含量及抗氧化活性存在显著性差异且70％乙醇溶液提取物表现出最高的总酚(219.01 mg GAE/g)、总黄酮含量(7.23 mg CE/g)及最强的DPPH自由基清除能力(35.46 mg TE/g)和还原能力(1.89 mmol FeSO4/g);总酚、总黄酮含量与DPPH自由基清除能力、还原能力之间呈正相关,与总抗氧化能力呈显著负相关,表明多酚类物质是青钱柳中主要的抗氧化剂.UPLC-QTOF-MS/MS分析70％乙醇溶液提取物并初步鉴定出22种化合物,包括2种有机酸、4种酚酸、5种黄酮、8种三萜皂苷类和3种酯类,其中酚酸和黄酮类化合物是主要的抗氧化活性成分,有机酸、三萜皂苷及酯类化合物可能是潜在的抗氧化活性成分.%The contents of total phenolics (TPC) and total flavonoids (TFC) and antioxidant activities (1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity,reducing power and total antioxidant capacity) in different solvent extracts from Cyclocarya paliurus leaves (CPL) obtained with water,70％ ethanol,ethyl acetate and n-hexane were determined by the 96-well plate method.The correlation between phenolics contents and antioxidant activities was investigated and the main bioactive constituents were identified by using ultra performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS).There were significant differences in the contents of total phenolics and total flavonoids and antioxidant activities among different extracts.The 70％ ethanol extract showed the highest contents of total phenolics (219.01 mg GAE/g) and total flavonoids (7.23 mg CE/g),and the strongest DPPH radical scavenging activity (35.46 mg TE/g) and reducing power (1.89 mmol FeSO4/g).Each bioactive component demonstrated positive correlations with DPPH radical scavenging ability and reducing power and negative correlations with total antioxidant capacity,indicating that polyphenols mainly account for the antioxidant activities of CPL extracts.The 70％ ethanol extract was analyzed by UPLC-QTOF-MS/MS,and a total of 22 compounds,including 2 organic acids,4 phenolic acids,5 flavonoids,8 triterpenoid saponins and 3 esters,were identified,among which,phenolic acids and flavonoids were the major antioxidant constituents,while organic acids,triterpenoid saponins and esters might be potential antioxidant components.