College of Food Science, South China Agricultural University, Guangzhou 510642, China.
College of Food Science, South China Agricultural University, Guangzhou 510642, China.
Int J Biol Macromol. 2021 Jan 15;167:845-853. doi: 10.1016/j.ijbiomac.2020.11.040. Epub 2020 Nov 9.
A water-soluble glucose-rich polysaccharide from dried 'Shixia' longan pulp (LPsx) has been isolated for the first time, and its structure and immuno-regulatory mechanism were studied. LPsx is a hetero-polysaccharide with the average molecular weight 4102 g/mol. It was mainly consisted of glucose (95.9%), and small proportions of arabinose (2.1%), galactose (1.0%), mannose (0.6%), and xylose (0.4%). As analyzed by NMR, LPsx was mainly composed of (1 → 6)-α-d-glucose and (1 → 6)-β-d-glucose, branched with α-d-glucose-(1→. The immunomodulatory activity study showed that LPsx significantly increased the phagocytosis of macrophages, and strongly promoted the production of NO, IL-1β, IL-6 and TNF-α. Moreover, LPsx could inhibit the inflammatory response induced by lipopolysaccharide. The immuno-regulatory mechanism of LPsx was studied using RNA- sequencing and receptors activity analyses. It was found that LPsx induced macrophage activation via Ca and CR3-mediated MAPKs and PI3K-AKT signaling pathways. The results would be helpful for revealing the health promoting mechanism of dried 'Shixia' longan in traditional Chinese medicine.
首次从干龙眼果肉（LPsx）中分离出一种水溶性富含葡萄糖的多糖，并研究了其结构和免疫调节机制。LPsx 是一种杂多糖，平均分子量为 4102g/mol。它主要由葡萄糖（95.9%）组成，还有少量的阿拉伯糖（2.1%）、半乳糖（1.0%）、甘露糖（0.6%）和木糖（0.4%）。通过 NMR 分析，LPsx 主要由（1→6）-α-d-葡萄糖和（1→6）-β-d-葡萄糖组成，支链由α-d-葡萄糖-（1→组成。免疫调节活性研究表明，LPsx 显著增加了巨噬细胞的吞噬作用，并强烈促进了 NO、IL-1β、IL-6 和 TNF-α的产生。此外，LPsx 可以抑制脂多糖诱导的炎症反应。通过 RNA 测序和受体活性分析研究了 LPsx 的免疫调节机制。结果表明，LPsx 通过 Ca 和 CR3 介导的 MAPKs 和 PI3K-AKT 信号通路诱导巨噬细胞活化。研究结果有助于揭示传统中药干龙眼促进健康的机制。
