不同采摘期连翘叶中总黄酮、总酚酸含量与 DPPH自由基清除能力的相关性

目的:研究不同采摘时期连翘叶的总黄酮、总酚酸含量的变化及其与清除2,2-二苯基-1-苦肼基自由基(2,2-diphenyl-1-picrylhydrazyl,DPPH)能力的关系。方法:连翘叶样品粉末脱脂后用60%甲醇超声波提取。采用DPPH自由基清除法评价不同采摘时期连翘叶的抗氧化能力。样品粗提取物总黄酮含量的测定采用亚硝酸钠法,总酚酸含量的测定采用Folin试剂法。采用SPSS 13.0分析软件对数据进行统计学处理。结果:不同采摘时期连翘叶的总黄酮、总酚酸含量以及清除DPPH自由基的能力存在着显著的差异;3月采摘的刚萌发幼叶表现出最高的总黄酮、总酚酸含量以及清除DPPH自由基的能力。相关性研究表明,连翘叶的总黄酮、总酚酸含量与清除DPPH自由基能力均存在显著正相关关系,其相关系数分别为0.886,0.841。结论:3月连翘叶的抗氧化能力和抗氧化物质含量都显著高于其他生长时期连翘叶,这显示从抗氧化方面而言连翘嫩叶刚萌发的时期是最佳的采摘时期,为较好的开发和利用连翘叶提供了理论依据。

Relationship Between Total Flavonoids, Total Phenolics and 2,2-diphenyl-1-picrylhydrazyl Radical Scavenging Activities during Growth of Forsythia suspensa Leaves

Objective: The changes of total flavonoid content, total phenolic content and antioxidant activity in Forsythia suspensa leaves during growth were measured, and the relationship between them was also investigated. Method: The sample powder of F. suspensa leaves was defatted and extracted with 60% methanol by ultrasound-assisted method. The antioxidant abilities were estimated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The total flavonoid content in each extract was investigated by the AlCl₃ coloring method, the total phenolic content was investigated by the Folin-ciocalteu method. Statistical comparisons and the correlation between antioxidant component and antioxidant activities were made with the version 13.0 of SPSS soft ware. Result: The results showed that the total flavonoid content, total phenolic content and DPPH radical scavenging activity in leaves were significantly different during growth, the leaves picked in march had the highest the total flavonoid content, total phenolic content, and DPPH radical scavenging capacity. There is a significant positive relationship between flavonoid content, phenolic content and DPPH scavenging capacity, and their correlation coefficients are 0.886 and 0.841, respectively. Conclusion: The F. suspensa leaf on March had the highest DPPH redical scavenging activity, the total flavonoid content and the total phenolic content, this suggest that fresh young leaf can be considered as a valuable sourse of antioxidant products.