College of Pharmacy, Hubei University of Chinese Medicine, Wuhan 430065, China; School of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China; Hubei Traditional Chinese Medicine and Health Food Engineering Research Center, Wuhan 430065, China.
School of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China.
Int J Biol Macromol. 2019 Jul 15;133:1201-1209. doi: 10.1016/j.ijbiomac.2019.04.087. Epub 2019 Apr 12.
A previously unknown, water-soluble polysaccharide, named DOTP-B, was isolated from the roots of the plant Dioscorea opposita Thunb, a well-known edible and medicinal plant in China. DOTP-B was found to be neutral in charge, with an average molecular weight of 5623 Da. Monosaccharide composition analysis by GC-MS revealed that DOTP-B was a hetero-polysaccharide consisting of glucose and galactose at a molar ratio of 14.6:1.0. Structural features of DOTP-B were investigated with a combination of chemical and instrumental methods, including complete acid hydrolysis, periodate oxidation, methylation, GC-MS, FTIR and several NMR spectra. Highly correlated results demonstrated that the main chain of DOTP-B consisted of →4)-α-d-glc(1 → residues, with about 6% internal →6)-β-d-gal(1 → residues. The antioxidant activity of DOTP-B was also evaluated as the EC values against DPPH and PTIO radicals were 2.1 ± 0.1 mg/mL and 1.6 ± 0.1 mg/mL, respectively. Therefore, the polysaccharide DOTP-B could be possibly developed as a promising natural antioxidant for application in medical and food industries.
从中国著名的食用和药用植物薯蓣（Dioscorea opposita Thunb）的根部分离得到一种以前未知的、水溶性多糖，命名为 DOTP-B。DOTP-B 带中性电荷，平均分子量为 5623 Da。通过 GC-MS 的单糖组成分析表明，DOTP-B 是一种由葡萄糖和半乳糖以摩尔比 14.6:1.0 组成的杂多糖。通过化学和仪器方法的组合，包括完全酸水解、高碘酸盐氧化、甲基化、GC-MS、FTIR 和几种 NMR 谱，研究了 DOTP-B 的结构特征。高度相关的结果表明，DOTP-B 的主链由→4)-α-d-glc（1→ 残基组成，约有 6%的内部→6)-β-d-gal（1→ 残基。还评估了 DOTP-B 的抗氧化活性，其对 DPPH 和 PTIO 自由基的 EC 值分别为 2.1±0.1 mg/mL 和 1.6±0.1 mg/mL。因此，多糖 DOTP-B 可能作为一种有前途的天然抗氧化剂开发，应用于医学和食品工业。
