该研究采用水提醇沉法从盐制巴戟天中提取粗多糖（SMP），经DEAE-52纤维素柱和葡聚糖凝胶Sephadex G 100柱分离纯化得到多糖（SMP-4），采用红外光谱、高效凝胶渗透凝胶色谱、气相色谱和核磁共振波对SMP-4进行结构表征，并以RAW264.7巨噬细胞为模型，通过测定其细胞增殖活性和细胞因子分泌水平来评价其免疫活性。多糖结构分析表明，SMP-4是由阿拉伯糖、半乳糖、鼠李糖、核糖、木糖、葡萄糖和甘露糖组成的，摩尔比例为：0.55:0.23:0.16:0.03:0.02:0.01:0.01，分子量为1.32×105 u的多糖。SMP-4具有六种糖苷键，其中→3)-D-Araf-(1→占比最高，为58.35%。在免疫活性评价分析中表明，与对照组相比，在15.625~500.000 μg/mL质量浓度范围内不影响RAW264.7细胞的增殖，同时能显著地促进肿瘤坏死因子-α（TNF-α）和白细胞介素-1β（IL-1β）的分泌。SMP-4质量浓度为500 μg/mL时，RAW264.7细胞分泌的TNF-α质量浓度最高，为2 100.00 pg/mL（P<0.001）；在31.25 μg/mL质量浓度下，RAW264.7细胞分泌的IL-1β质量浓度最高，为14.50 pg/mL（P<0.05）。综上，SMP-4表现出良好免疫活性，具有成为一种天然的免疫调节剂的潜力。

In this study the polysaccharides from salt-processed Morinda officinalis SMP was extracted by water extraction and ethanol precipitation, and then purified sequentially by DEAE-52 cellulose and Sephadex-G100 columns, to yield a purified polysaccharide (named SMP-4). Fourier transform infrared spectroscopy, high performance gel permeation chromatography, gas chromatography and nuclear magnetic resonance were employed to characterize the structural properties of SMP-4, and its immunomodulatory activities were examined in Macrophage RAW264.7 through determining its cell proliferation activity and levels of secreted cytokines. The polysaccharide structure analysis showed that SMP-4 consisted of arabinose, galactose, rhamnose, ribose, xylose, glucose and mannose in the molar ratio of 0.55:0.23:0.16:0.03:0.02:0.01:0.01, and had a molecular weight of 1.32×105 u. SMP-4 had six kinds of glycosidic bonds, with →3)-D-linked-Araf-(1→ accounting for the highest proportion (58.35%). The immunological activity analyses showed that the proliferation of RAW264.7 cells was not affected in the concentration range of 15.625~500.000 μg/mL as compared with the control group, whilst the secretions of tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were significantly promoted. At a SMP-4 concentration of 500 μg/mL, the amount of TNF-α secreted by RAW264.7 cells reached the highest level (2 100.00 pg/mL) (P<0.001); At a SMP-4 concentration of 31.25 μg/mL, RAW264.7 cells secreted the highest amount of IL-1β (14.50 pg/mL) (P<0.05). In conclusion, SMP-4 exhibited a good immune activity and has the potential to be a natural immunomodulator.

财政部和农业农村部国家现代农业产业技术体系资助（CARS-21）；广东省自然科学基金面上项目（2020A151501268）；广东省重点领域研发计划项目（2020B020226008）