Zou Xian-Guo, Cao Yu-Qin, Li Jing-Jing, Guan Xiao-Qian, Cai Ming, Sun Pei-Long, Yang Kai
College of Food Science and Technology, Zhejiang University of Technology, Hangzhou, China.
Key Laboratory of Food Macromolecular Resources Processing Technology Research, China National Light Industry, Zhejiang University of Technology, Hangzhou, China.
Front Nutr. 2022 Aug 11;9:981099. doi: 10.3389/fnut.2022.981099. eCollection 2022.
In this study, cascade membrane technology was applied to classify polysaccharides from the peels of stem lettuce (PPSLs), and three graded polysaccharides (PPSL100, PPSL10, and PPSL1) were obtained using ultrafiltration membranes of 100, 10, and 1 kDa in sequence. The physicochemical properties and immune-modulatory activity of three PPSLs fractions were analyzed and compared. Results showed that all three fractions have characteristic absorption peak of polysaccharides determined by FT-IR, and their monosaccharide composition only consisted of glucose determined by HPLC. PPSL10 had the highest contents of total sugar (88.09 ± 3.52%), uronic acid (2.55 ± 0.10%), and sulfate group (4.15 ± 0.20%). Besides, all three fractions exhibited immune-enhancing activities using RAW264.7 macrophages model, and PPSL10 was the best able to promote phagocytosis of neutral red and nitric oxide generation, which might relate to the high contents of above compositions and medium molecular weight (32 kDa). The findings indicated that PPSL10 could be developed as immune-modulator in the field of functional foods.
在本研究中，采用级联膜技术对莴笋皮多糖（PPSLs）进行分级，依次使用截留分子量为100、10和1 kDa的超滤膜获得了三种分级多糖（PPSL100、PPSL10和PPSL1）。对三种PPSLs级分的理化性质和免疫调节活性进行了分析和比较。结果表明，通过傅里叶变换红外光谱（FT-IR）测定，所有三个级分均具有多糖的特征吸收峰，通过高效液相色谱（HPLC）测定，它们的单糖组成仅由葡萄糖组成。PPSL10的总糖（88.09±3.52%）、糖醛酸（2.55±0.10%）和硫酸基团（4.15±0.20%）含量最高。此外，在RAW264.7巨噬细胞模型中，所有三个级分均表现出免疫增强活性，且PPSL10最能促进中性红吞噬和一氧化氮生成，这可能与上述成分的高含量和中等分子量（32 kDa）有关。研究结果表明，PPSL10可开发成为功能性食品领域的免疫调节剂。
