Institute of Biological and Medical Engineering, Guangdong Academy of Sciences, Guangzhou, Guangdong 510316, China; Guangdong Province Engineering Research Center for Green Technology of Sugar Industry, Guangzhou, Guangdong 510316, China.
Department of Chemistry, The University of Hong Kong, Hong Kong.
Int J Biol Macromol. 2024 May;267(Pt 1):131472. doi: 10.1016/j.ijbiomac.2024.131472. Epub 2024 Apr 8.
Lignin nanoparticles (LNPs) have gained significant attention for their potential as natural antioxidants. This study investigated the effect of various pretreatment methods on the lignin structure and subsequent antioxidant activity of LNPs. Among four pretreated LNPs, hydrothermal LNPs exhibited the highest antioxidant activity, surpassing unpretreated, acid-pretreated and kraft LNPs, with an impressive efficacy of 91.6%. The relationship between LNPs' structure and antioxidant activity was revealed by 2D heteronuclear singular quantum correlation (HC HSQC) and P nuclear magnetic resonance (NMR). HC HSQC suggested the cleavage of β-O-4 ether bonds, as well as a decrease in ferulic acid and p-coumaric acid, which directly influenced the antioxidant activity of LNPs. P NMR demonstrated a positive correlation between the total hydroxyl group content and the antioxidant activity. Besides, an isothermal kinetic model for scavenging free radicals was established based on Langmuir kinetic model instead of Freundlich model. Moreover, multilayer LNPs, based on layer-by-layer self-assembly, were prepared and exhibited remarkable antioxidant activity of 95.8%. More importantly, when blended with pure cosmetic cream, the multilayer LNPs maintained antioxidant activity of 86.7%. These finding may promote the practical applications of biomolecules, e.g. lignin additives in cosmetics and pharmaceuticals.
木质素纳米颗粒 (LNP) 因其作为天然抗氧化剂的潜力而受到广泛关注。本研究探讨了不同预处理方法对 LNP 结构和随后抗氧化活性的影响。在四种预处理的 LNP 中，水热处理的 LNP 表现出最高的抗氧化活性，超过了未经预处理、酸预处理和 kraft LNP，其功效高达 91.6%。2D 异核单量子相关 (HC HSQC) 和 P 核磁共振 (NMR) 揭示了 LNP 结构与抗氧化活性之间的关系。HC HSQC 表明β-O-4 醚键的断裂以及阿魏酸和对香豆酸的减少，这直接影响了 LNP 的抗氧化活性。P NMR 表明总羟基含量与抗氧化活性之间存在正相关关系。此外，基于 Langmuir 动力学模型而不是 Freundlich 模型，建立了自由基清除的等温动力学模型。此外，基于层层自组装制备了多层 LNP，其抗氧化活性高达 95.8%。更重要的是，当与纯化妆品霜混合时，多层 LNP 仍保持 86.7%的抗氧化活性。这些发现可能促进生物分子（如木质素添加剂）在化妆品和制药中的实际应用。
