§Department of Nutrition and Food Science, University of Maryland, College Park, Maryland 20742, United States.
J Agric Food Chem. 2015 Apr 1;63(12):3219-28. doi: 10.1021/acs.jafc.5b00494. Epub 2015 Mar 19.
A pectic polysaccharide (APPS) was purified from the cold alkali extract of alfalfa stem and characterized to be a rhamnogalacturonan I (RG-I) type pectin with the molecular weight of 2.38 × 10(3) kDa and a radius of 123 nm. The primary structural analysis indicated that APPS composed of a →2)-α-l-Rhap-(1→4)-α-d-GalpA-(1→ backbone with 12% branching point at C-4 of Rhap forming side chains by l-arabinosyl and d-galactosyl oligosaccharide units. Transmission electron microscopy (TEM) analysis revealed a primary linear-shaped structure with a few branches in its assembly microstructures. The thermal decomposition evaluation revealed the stability of APPS with an apparent activation energy (Ea) of 226.5 kJ/mol and a pre-exponential factor (A) of 2.10 × 10(25)/s, whereas its primary degradation occurred in the temperature range from 215.6 to 328.0 °C. In addition, APPS showed significant anti-inflammatory effect against mRNA expressions of the pro-inflammatory cytokine genes, especially for IL-1β, suggesting its potential utilization in functional foods and dietary supplement products.
从紫花苜蓿茎的冷碱提取物中纯化出一种果胶多糖（APPS），其特征是属于鼠李半乳糖醛酸 I 型（RG-I）果胶，分子量为 2.38×103 kDa，半径为 123nm。初步结构分析表明，APPS 由→2）-α-l-Rhap-（1→4）-α-d-GalpA-（1→主链组成，在 Rhap 的 C-4 位有 12%的分支点，通过 l-阿拉伯糖基和 d-半乳糖基低聚糖单元形成侧链。透射电子显微镜（TEM）分析显示，其组装微观结构中存在初级线性形状结构和少量分支。热分解评估表明 APPS 具有稳定性，表观活化能（Ea）为 226.5 kJ/mol，指数前因子（A）为 2.10×1025/s，而其主要降解发生在 215.6 至 328.0°C 的温度范围内。此外，APPS 对促炎细胞因子基因的 mRNA 表达表现出显著的抗炎作用，特别是对 IL-1β，表明其在功能性食品和膳食补充产品中的潜在应用。
