To understand the influence of lignin characteristics on their antioxidant activities, lignins were isolated from Broussonetia papyrifera by organosolv pretreatment at different temperatures. The physicochemical features of the lignins were investigated by GPC, ³¹P NMR and 2D HSQC NMR analyses. An increase of organosolv pretreatment temperature resulted in a decrease of M_w and an increase of the phenolic hydroxyl group content in the isolated lignin. The lignins extracted at higher organosolv pretreatment temperature showed higher antioxidant activity according to the IC₅₀ determined using DPPH and ABTS. The correlations between the physicochemical properties of organosolv lignins and their antioxidant activities were studied. The contents of phenolic hydroxyl groups, especially syringyl and guaiacyl, and double bonds in the C_α position had positive effects on the antioxidant activity of the lignins. On the other hand, M_w and aliphatic hydroxyl groups of the lignins exhibited negative correlations with the antioxidant activity.

中文翻译：

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布鲁氏假单胞菌有机溶剂木质素的理化性质与其抗氧化活性的关系

为了了解木质素特性对其抗氧化活性的影响，在不同温度下通过有机溶剂预处理从纸莎草中分离了木质素。通过GPC，³¹ P NMR和2D HSQC NMR分析研究了木质素的理化特性。有机溶剂预处理温度的升高导致分离的木质素中M _w的降低和酚羟基含量的增加。根据IC _50，在较高的有机溶剂预处理温度下提取的木质素显示出较高的抗氧化活性使用DPPH和ABTS确定。研究了有机溶剂木质素的理化性质与其抗氧化活性之间的关系。酚羟基基团在C的含量，特别是紫丁香和愈创木基和双键的_α位置对木质素的抗氧化活性的积极影响。另一方面，木质素的M _w和脂肪族羟基与抗氧化活性呈负相关。