College of Ecological and Environmental Engineering, Qinghai University, Xining 810016, China.
State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810016, China.
Molecules. 2022 Mar 3;27(5):1674. doi: 10.3390/molecules27051674.
The discovery of safe and effective plant polysaccharides with immunomodulatory effects has become a research hotspot. Raspberry is an essential commercial fruit and is widely distributed, cultivated, and consumed worldwide. In the present study, a homogeneous acidic polysaccharide (RPP-2a), with a weight-average molecular weight (Mw) of 55582 Da, was isolated from the pulp of raspberries through DEAE-Sepharose Fast Flow and Sephadex G-200 chromatography. RPP-2a consisted of rhamnose, arabinose, galactose, glucose, xylose, galacturonic acid and glucuronic acid, with a molar ratio of 15.4:9.6:7.6:3.2:9.1:54.3:0.8. The results of Fourier transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometer (GC-MS), 1D-, and 2D-nuclear magnetic resonance (NMR) analyses suggested that the backbone of RPP-2a was primarily composed of →2)--L-Rha-(1→, →2,4)--L-Rha-(1→, →4)--D-GalA-(1→, and →3,4)--D-Glc-(1→ sugar moieties, with side chains of -L-Ara-(1→, -L-Ara-(1→, and -D-Gal-(1→3)--D-Gal-(1→ residues linked to the O-4 band of rhamnose and O-3 band of glucose residues. Furthermore, RPP-2a exhibited significant macrophage activation activity by increasing the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and the expression of inducible nitric oxide synthase (iNOS) and cytokines at the transcriptional level in RAW264.7 cells. Overall, the results indicate that RPP-2a can be utilized as a potential natural immune-enhancing agent.
具有免疫调节作用的安全有效的植物多糖的发现已成为研究热点。树莓是一种重要的商业水果，在世界范围内广泛种植和食用。本研究从树莓果肉中通过 DEAE-Sepharose Fast Flow 和 Sephadex G-200 层析分离得到一种均一的酸性多糖（RPP-2a），其重均分子量（Mw）为 55582 Da。RPP-2a 由鼠李糖、阿拉伯糖、半乳糖、葡萄糖、木糖、半乳糖醛酸和葡萄糖醛酸组成，摩尔比为 15.4:9.6:7.6:3.2:9.1:54.3:0.8。傅里叶变换红外光谱（FT-IR）、气相色谱-质谱联用（GC-MS）、一维和二维核磁共振（NMR）分析结果表明，RPP-2a 的骨架主要由 →2)--L-Rha-(1→, →2,4)--L-Rha-(1→, →4)--D-GalA-(1→和 →3,4)--D-Glc-(1→糖单元组成，侧链为 -L-Ara-(1→, -L-Ara-(1→和 -D-Gal-(1→3)--D-Gal-(1→残基连接到鼠李糖的 O-4 位和葡萄糖的 O-3 位。此外，RPP-2a 在 RAW264.7 细胞中通过增加一氧化氮（NO）、肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）、白细胞介素-1β（IL-1β）的产生以及诱导型一氧化氮合酶（iNOS）和细胞因子的转录水平表达，显示出显著的巨噬细胞激活活性。总体而言，结果表明 RPP-2a 可用作潜在的天然免疫增强剂。
