1种水溶性霸王花多糖的分离纯化及结构鉴定

摘要

Objective: To extract and purify polysaccharide fractions from the flower of Hylocereus undatus (Haw.) (H. undatus) Britton & Rose and investigate their physicochemical, spectroscopic, and structural properties. Methods:The crude water-soluble polysaccharide (HUP) was extracted, precipitated, deproteinized and lyophilized from flower of H. undatus. A homogeneous polysaccharide fraction, designated HUP0, was obtained by consecutive DEAE-cellulose and Sephadex G-100 column chromatography. Structural characterization of the polysaccharide fraction was conducted using high performance size exclusion chromatography coupled with multi-angle laser light scattering and refractive index detection (HPSEC-MALLS-RID), Fourier transform infrared (FT-IR) spectroscopy, high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy. Results: The weight-average molecular mass, intrinsic viscosity, specific rotation and mean diameter of HUP0 were measured to be 33.24 kD, 47.16 mL/g, +69°, and 196.96 nm, respectively. The FT-IR spectra showed that HUP0 was a neutral polysaccharide, which mainly contained β-configuration. Methylation, HPLC and NMR analyses indicated that HUP0 was a (1→4)-β-D-galactan.%目的:从霸王花中提取分离和纯化多糖,并对其理化性质、光谱学特征和结构特征进行研究.方法:霸王花经水提醇沉、脱蛋白、冷冻干燥得到水溶性粗多糖(hylocereus undatus polysaccharide,HUP),再通过DEAE-Cellulose 52纤维素柱和Sephadex G-100凝胶柱层析分离纯化,得到1种水溶性均一多糖HUP0.对获得的纯化组分采用傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FT-IR)、高效分子排阻色谱、气相色谱-质谱联用和核磁共振波谱(nuclear magnetic resonance,NMR)等方法进行化学结构分析.结果:经纯化后得到均一的霸王花多糖样品HUP0,分子质量为33.24 kD,特性黏度(η)为47.16 mL/g,比旋度为+69°,平均粒径为196.96 nm;FT-IR图谱结果表明HUP0是中性糖且以β-构型为主;结合高效液相色谱、单糖组成、甲基化分析、NMR对HUP0的结构进行鉴定分析后,表明HUP0为(1→4)-β-D-半乳聚糖.