Unraveling the Structure–Antioxidant Property Relationship of Lignin: Insights from Botanical Sources and pH-Controlled Fractionation

作者：Kongyan Li, YiRun Liu, Haipeng Xu, Wei Zhong, Yongcan Jin, Min Liu, Wenjuan Wu · 发表于：Biomacromolecules · 年份：2025 · DOI：10.1021/acs.biomac.5c00866 · 被引用次数：9 · 研究领域：Lignin and Wood Chemistry、Fermentation and Sensory Analysis、Phytochemicals and Antioxidant Activities

This study employs biomass source selection (hardwood, gramineae, softwood) and pH-controlled fractionation (pH 1, 7, 9) to analyze lignin structure and optimize antioxidant capacity. Acid-precipitated hardwood lignin exhibits higher antioxidant capacity (IC 50 = 0.74 mg/mL, TEAC = 1.88 μmol/mg), attributed to higher Ph–OH (3.35 mmol/g, TPC = 0.31 GAE/g) and the possible synergistic effect of the S/G ratio (1.63). In the stepwise pH fractionation of aspen black liquor, the fraction at pH 1 (A1) exhibited the best antioxidant activity (IC 50 = 0.64 mg/mL, TEAC = 2.01 μmol/mg) and the highest Ph–OH (3.68 mmol/g, TPC = 0.37 GAE/g), while fraction A9 exhibited the weakest antioxidant activity (Ph–OH = 2.49 mmol/g, TPC = 0.3 GAE/g). Ph–OH showed the strongest correlation with IC 50 (| r | = 0.94), followed by M w (| r | = 0.89) (Ph–OH > M w > −COOH > Alk–OH). Adjusting M w can complement the enhancement of Ph–OH, thereby optimizing the antioxidant function.