树莓多糖组分RPP-6的分离、结构表征及其体外免疫和抗氧化活性研究

旨在对从树莓粗多糖中分离纯化出的树莓多糖组分RPP-6进行结构表征及体外免疫活性和抗氧化活性研究。采用DEAE-Sepharose Fast Flow和Sephadex G-200对树莓粗多糖进行分离纯化。结合高效凝胶渗透色谱法（High-Performance Gel Permeation Chromatography，HPGPC）、傅里叶红外光谱法（Fourier Transform Infrared Spectroscopy，FT-IR）、气相色谱-质谱联用（Gas Chromatography and Mass Spectrometry，GC-MS）和甲基化等方法对RPP-6的结构进行表征。利用小鼠巨噬细胞RAW264.7和自由基清除试验研究RPP-6的体外免疫与抗氧化活性。结果表明，RPP-6是一种酸性杂多糖，由阿拉伯糖、葡萄糖、半乳糖、鼠李糖和甘露糖组成，摩尔比为37.8∶30.8∶21.4∶6.0∶3.9 。RPP-6的峰位分子质量为7.645 ku、重均分子质量为7.769 ku、数均分子质量为6.310 ku。RPP-6中存在15种单糖连接方式，其中Araf-(1→、→4,6)-Glcp- (1→、→4)-Galp-(1→和→4)-Xylp-(1→为主要连接方式，含量分别为20.64%、8.59%、24.04%和 16.92%。RPP-6能明显提高小鼠巨噬细胞RAW264.7的活力和吞噬能力，并促进细胞中TNF-α（Tumor Necrosis Factor，TNF）、IL-6（Interleukin-6，IL-6）、IL-1β（Interleukin-1β，IL-1β）和NO（Nitric Oxide，NO）释放。RPP-6对ABTS·⁺具有较高的清除作用，对DPPH·的清除作用不明显。表明RPP-6是一种多支链的均一酸性杂多糖，具有显著的免疫增强活性和一定的抗氧化活性。

Isolation, Structural Characterization, Immunoregulatory and Antioxidant Activity of Raspberry Polysaccharide RPP-6 in Vitro

In the present study, the raspberry polysaccharide RPP-6 was isolated from raspberry pulp,and its structural characteristics,immunomodulatory and antioxidant activities were studied in vitro. RPP-6 was isolated and purified by DEAE-Sepharose Fast Flow and Sephadex G-200 chromatography and thestructural characteristics of RPP-6 were studied by high-performance gel permeation chromatography (HPGPC), Fourier-transform infrared spectroscopy (FT-IR), gas chromatography-mass spectroscopy (GC-MS) and methylation. RAW264.7 macrophages and free radical scavenging tests were conducted to evaluate the immunomodulatory and antioxidant activities of RPP-6.The results showed that RPP-6 was composed of arabinose, glucose, galactose, rhamnose and mannose at a molar ratios of 37.8∶30.8∶21.4∶6.0∶3.9,respectively. The peak molecular mass, average molecular mass and number average molecular mass were 7.645 ku,7.769 ku, and 6.310 ku, respectively. RPP-6 was composed of 15 glycosyl linkages patterns, among which Araf-(1→, →4,6)-Glcp-(1→, →4)-Galp-(1→ and →4)-Xylp-(1→ were the main connection modes of sugar residues, accounting for about 20.64%, 8.59%, 24.04%, and 16.92%, respectively. RPP-6 significantly promoted the proliferation and phagocytosis of RAW264.7 cells and increased the release of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, and nitric oxide (NO) in RAW264.7 cells. RPP-6 exhibited strong ABTS·⁺ radical scavenging ability,but exhibited no DPPH· free radical scavenging ability. In conclusion, RPP-6 is a homogeneous acidic heteropolysaccharide with a complex multi-branched structure, and has significant immune-enhancing activity and certain antioxidant activity.