Song Kaiqin, Yu Liping, Yang Shoulu, Cao Yan, Li Lifen, Wu Zhigang, Shi Hongtao, Ma Qiaorun
College of Forestry, Guizhou University, Guiyang 550025, China.
Guizhou Academy of Forestry, Guiyang 550025, China.
ACS Omega. 2024 Sep 19;9(39):40956-40969. doi: 10.1021/acsomega.4c06259. eCollection 2024 Oct 1.
Deep eutectic solvents (DESs) composed of choline chloride as hydrogen bond acceptors (HBAs) and six organic acids as hydrogen bond donors (HBDs) were used to extract lignin from bamboo ( (Carrière) J. Houz.). The structures of the DES-extracted lignin samples were analyzed by Fourier-transform infrared spectroscopy (FT-IR), UV-visible spectroscopy (UV-vis), thermogravimetric analysis (TG), and gel permeation chromatography (GPC) to investigate the relationship between the chemical structure of lignin and its antioxidant activity. The results showed that DES treatment removed a large portion of the lignin (73.37-86.38%) from bamboo, and the chemical structure of lignin was changed due to the use of different types of HBDs. The extracted lignin exhibited good UV-vis light shielding properties, thermal stability, and antioxidant activity. Moreover, the total phenolic hydroxyl content of lignins was positively correlated with their antioxidant activity, while the molecular weight of lignins was negatively correlated with their antioxidant activity. Notably, lignin extracted with choline chloride--toluenesulfonic acid had the highest phenolic hydroxyl content and lower molecular weight, showing the strongest antioxidant activity (IC = 417.69 μg/mL, IC = 58.62 μg/mL). This study confirms the high thermal stability, excellent antioxidant activity, and UV shielding properties of lignin extracted with choline chloride-organic acid DESs, suggesting its potential application in the fields of antioxidants and material modifiers.
以氯化胆碱作为氢键受体（HBAs）和六种有机酸作为氢键供体（HBDs）组成的低共熔溶剂（DESs）用于从竹子（（卡里埃尔）J. 胡兹）中提取木质素。通过傅里叶变换红外光谱（FT-IR）、紫外可见光谱（UV-vis）、热重分析（TG）和凝胶渗透色谱（GPC）对经DES提取的木质素样品的结构进行分析，以研究木质素的化学结构与其抗氧化活性之间的关系。结果表明，DES处理从竹子中去除了大部分木质素（73.37 - 86.38%），并且由于使用了不同类型的HBDs，木质素的化学结构发生了变化。提取的木质素表现出良好的紫外可见光屏蔽性能、热稳定性和抗氧化活性。此外，木质素的总酚羟基含量与其抗氧化活性呈正相关，而木质素的分子量与其抗氧化活性呈负相关。值得注意的是，用氯化胆碱 - 对甲苯磺酸提取的木质素具有最高的酚羟基含量和较低的分子量，表现出最强的抗氧化活性（IC₅₀ = 417.69 μg/mL，IC₁₀₀ = 58.62 μg/mL）。本研究证实了用氯化胆碱 - 有机酸DESs提取的木质素具有高热稳定性、优异的抗氧化活性和紫外屏蔽性能，表明其在抗氧化剂和材料改性剂领域的潜在应用。
