School of Chemistry and Chemical Engineering, North Minzu University, Yinchuan 750021, China.
School of Chemistry and Chemical Engineering, North Minzu University, Yinchuan 750021, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2025 Feb 5;326:125204. doi: 10.1016/j.saa.2024.125204. Epub 2024 Sep 23.
Lycium barbarum polysaccharides (LBPs) is one of the most important active substances in Lycium barbarum (LB). It is a challenge to quantitatively determine the content due to their complex structures and lack of suitable reference standard in practice. In this study, a quantitative analysis method of LBPs in LB was established based on Fourier-transform infrared spectroscopy (FTIR). The stretching vibration of CO on the pyranose ring of saccharide at 921 cm was selected as the characteristic absorption band by theoretical calculation, which can't be impacted by the preparation methods and interfered by the component monosaccharides. The molecular weight CRM of dextran (Mw 63.3 kDa) served as the reference standard. The introducing internal standard (KSCN) can obtain a good precision (RSD = 1.10 %) and effectively compensate for the analysis errors caused by the environment, quality loss and uneven distribution during the tablet pressing processes. The methodological verification suggested that the method had good accuracy according to the recovery rate (96.61 %-105.45 %) and the blank recovery (92.39 %-99.37 %), respectively. The LOD and LOQ of CRMD were 0.10 mg and 0.32 mg, respectively. The polysaccharide content of LB from 24 different regions (0.50-2.54 %) and 10 batches of LB extracts (7.09-10.56 %) determined by the developed method less than the ones using phenol-sulfuric acid assay (1.95 %-4.83 % for LB and 9.83-15.53 % for extracts, respectively). The established method based on FTIR could be served as a supplement to phenol-sulfuric acid assay and a rapid quantitative assay for polysaccharides products. In additional, this study provided a new idea for the quantitative analysis of plant polysaccharides.
枸杞多糖（LBPs）是枸杞（LB）中最重要的活性物质之一。由于其复杂的结构和缺乏合适的参考标准，实际上很难定量测定其含量。在本研究中，建立了一种基于傅里叶变换红外光谱（FTIR）的枸杞中 LBPs 的定量分析方法。通过理论计算，选择糖环上 CO 的伸缩振动作为特征吸收带，位于 921 cm处，该吸收带不会受到制备方法的影响，也不会受到单糖成分的干扰。葡聚糖（Mw 63.3 kDa）的分子质量 CRM 用作参考标准。引入内标（KSCN）可以获得良好的精密度（RSD = 1.10%），并有效补偿压片过程中环境、质量损失和分布不均匀引起的分析误差。方法学验证表明，该方法的回收率（96.61%-105.45%）和空白回收率（92.39%-99.37%）分别具有良好的准确性。CRMD 的 LOD 和 LOQ 分别为 0.10 mg 和 0.32 mg。通过开发的方法测定的来自 24 个不同地区的 LB（0.50-2.54%）和 10 批 LB 提取物（7.09-10.56%）的多糖含量，均小于苯酚-硫酸比色法（LB 为 1.95%-4.83%，提取物为 9.83-15.53%）的含量。基于 FTIR 的建立方法可以作为苯酚-硫酸比色法的补充，也是多糖产品的快速定量分析方法。此外，本研究为植物多糖的定量分析提供了新的思路。
