Lin Ya-Ru, Guan Qing-Yun, Li Ling-Yu, Tang Zhi-Mei, Zhang Qiang, Zhao Xin-Huai
School of Biology and Food Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China.
Research Centre of Food Nutrition and Human Healthcare, Guangdong University of Petrochemical Technology, Maoming 525000, China.
Foods. 2021 Dec 21;11(1):14. doi: 10.3390/foods11010014.
The soluble polysaccharides from a non-conventional and edible plant purslane ( L.), namely PSPO, were prepared by the water extraction and ethanol precipitation methods in this study. The obtained PSPO were selenylated using the NaSeO-HNO method to successfully prepare two selenylated products, namely SePSPO-1 and SePSPO-2, with different selenylation extents. The assay results confirmed that SePSPO-1 and SePSPO-2 had respective Se contents of 753.8 and 1325.1 mg/kg, while PSPO only contained Se element about 80.6 mg/kg. The results demonstrated that SePSPO-1 and SePSPO-2 had higher immune modulation than PSPO ( < 0.05), when using the two immune cells (murine splenocytes and RAW 264.7 macrophages) as two cell models. Specifically, SePSPO-1 and SePSPO-2 were more active than PSPO in the macrophages, resulting in higher cell proliferation, greater macrophage phagocytosis, and higher secretion of the immune-related three cytokines, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β. Meanwhile, SePSPO-1 and SePSPO-2 were more potent than PSPO in the concanavalin A- or lipopolysaccharide-stimulated splenocytes in cell proliferation, or more able than PSPO in the splenocytes to promote interferon-γ secretion but suppress IL-4 secretion, or more capable of enhancing the ratio of T-helper (CD4) cells to T-cytotoxic (CD8) cells for the T lymphocytes than PSPO. Overall, the higher selenylation extent of the selenylated PSPO mostly caused higher immune modulation in the model cells, while a higher polysaccharide dose consistently led to the greater regulation effect. Thus, it is concluded that the employed chemical selenylation could be used in the chemical modification of purslane or other plant polysaccharides, when aiming to endow the polysaccharides with higher immuno-modulatory effect on the two immune cells.
本研究采用水提取和乙醇沉淀法，从一种非常规可食用植物马齿苋（Portulaca oleracea L.）中制备了可溶性多糖，即PSPO。采用Na₂SeO₃-HNO₃法对所得的PSPO进行硒化，成功制备了两种硒化程度不同的硒化产物，即SePSPO-1和SePSPO-2。测定结果证实，SePSPO-1和SePSPO-2的硒含量分别为753.8和1325.1 mg/kg，而PSPO仅含约80.6 mg/kg的硒元素。结果表明，以两种免疫细胞（小鼠脾细胞和RAW 264.7巨噬细胞）为细胞模型时，SePSPO-1和SePSPO-2的免疫调节作用高于PSPO（P<0.05）。具体而言，SePSPO-1和SePSPO-2在巨噬细胞中的活性高于PSPO，导致细胞增殖更高、巨噬细胞吞噬作用更强，以及包括肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）和IL-1β在内的三种免疫相关细胞因子的分泌更高。同时，在刀豆蛋白A或脂多糖刺激的脾细胞中，SePSPO-1和SePSPO-2在细胞增殖方面比PSPO更有效，或者在脾细胞中比PSPO更能促进干扰素-γ分泌但抑制IL-4分泌，或者比PSPO更能提高T淋巴细胞中辅助性T（CD4）细胞与细胞毒性T（CD8）细胞的比例。总体而言，硒化PSPO的硒化程度越高，在模型细胞中的免疫调节作用大多越强，而多糖剂量越高，调节效果始终越显著。因此得出结论，当旨在赋予多糖对这两种免疫细胞更高的免疫调节作用时，所采用的化学硒化方法可用于马齿苋或其他植物多糖的化学修饰。
