Tian Dayu, Huang Lan, Zhang Zhao, Tian Zhenfeng, Ge Shaolin, Wang Chenghui, Hu Yonghua, Wang Ying, Yang Jun
Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, 230026, People's Republic of China.
Technology Center, China Tobacco Auhui Industrial Co., Ltd., No.9 Tianda Road, Hefei, 230088, People's Republic of China; Key Laboratory of Tobacco Chemistry in Anhui Province, China Tobacco Auhui Industrial Co., Ltd., No.9 Tianda Road, Hefei, 230088, People's Republic of China.
Carbohydr Res. 2023 Apr;526:108790. doi: 10.1016/j.carres.2023.108790. Epub 2023 Mar 13.
Cellulose is an important component of tobacco (Nicotiana tabacum L.) cell walls, which can be precursors for many harmful compounds in smoke. Traditional cellulose content analysis methods involve sequential extraction and separation steps, which are time-consuming and environmentally unfriendly. In this study, a novel method was first introduced to analyze cellulose content in tobacco via two-dimensional heteronuclear single quantum coherence (2D HSQC) NMR spectroscopy. The method was based on derivatization approach to allow the dissolution of insoluble polysaccharide fractions of tobacco cell walls in DMSO‑d/pyridine-d (4:1 v/v) for NMR analysis. The NMR results suggested that besides the main NMR signals of cellulose, partial signals of hemicellulose including mannopyranose, arabinofuranose, and galactopyranose units could also be identified. In addition, the utilization of relaxation reagents has proved to be an effective way to improve the sensitivity of 2D NMR spectroscopy, which was beneficial for quantification of biological samples with limited quantities. To overcome the limitations of quantification using 2D NMR, the calibration curve of cellulose with 1,3,5-trimethoxybenzene as internal reference was constructed and thus the accurate measurement of cellulose in tobacco was achieved. Compared with the chemical method, the interesting method was simple, reliable, and environmentally friendly, which provided a new insight for quantitative determination and structure analysis of plant macromolecules in complex samples.
纤维素是烟草（Nicotiana tabacum L.）细胞壁的重要组成部分，它可能是烟雾中许多有害化合物的前体。传统的纤维素含量分析方法涉及一系列提取和分离步骤，既耗时又不环保。在本研究中，首次引入了一种通过二维异核单量子相干（2D HSQC）核磁共振光谱分析烟草中纤维素含量的新方法。该方法基于衍生化方法，使烟草细胞壁中不溶性多糖部分能够溶解在氘代二甲基亚砜/氘代吡啶（4:1 v/v）中用于核磁共振分析。核磁共振结果表明，除了纤维素的主要核磁共振信号外，还可以识别出包括甘露吡喃糖、阿拉伯呋喃糖和半乳糖吡喃糖单元在内的部分半纤维素信号。此外，使用弛豫试剂已被证明是提高二维核磁共振光谱灵敏度的有效方法，这有利于对少量生物样品进行定量分析。为了克服二维核磁共振定量分析的局限性，构建了以1,3,5 -三甲氧基苯为内标的纤维素校准曲线，从而实现了烟草中纤维素的准确测定。与化学方法相比，该方法简单、可靠且环保，为复杂样品中植物大分子的定量测定和结构分析提供了新的思路。
