以正红菇子实体分离纯化后得到的单一多糖HAP-Ⅰ为研究对象，用高效凝胶渗透色谱（GPC）结合葡聚糖凝胶Sephadex G-100的分离结果鉴定其分子量分布及纯度，利用FT-IR、GC、高碘酸氧化和Smith降解、NMR研究HAP-I分子内部结构；通过体外抗氧化法清除自由基DPPH、O2-、OH以及还原力测定，评价HAP-I抗氧化能力。结果表明，HAP-Ⅰ重均相对分子量MW 16860 u；FT-IR显示HAP-Ⅰ具有多糖的特征吸收峰且为含氨基的β型D-葡萄糖环构型；GC结果显示HAP-Ⅰ含鼠李糖、甘露糖、葡萄糖、半乳糖4种单糖，摩尔比为1:8.29:7.45:18.13；高碘酸氧化和Smith降解结果表明，HAP-I是含有甘露糖苷的D-吡喃葡萄糖环，包括α构型和β构型，不含有1→4糖苷键，由66.7% 1→3糖苷键，22.24%的1→6、1→糖残基和11.06% 1→2糖残基组成；NMR表明HAP-I是含有半乳糖基的吡喃糖，既有α构型，也有β构型；体外抗氧化结果表明，HAP-I有较强的清除自由基DPPH、O2-、OH作用和还原能力。

A purified single polysaccharide (HAP-I) that was isolated from the fruit bodies of Russula vinosa was used as the study object, and its molecular weight distribution and purity were determined based on the separation results from gel permeation chromatography (GPC) with dextran-based Sephadex G-100. The chemical structure of the HAP-I molecule was studied by Fourier transform infrared spectroscopy (FT-IR), gas chromatography (GC), periodate oxidation, Smith degradation, and nuclear magnetic resonance (NMR). The antioxidant activity of HAP-I was evaluated by measuring its reducing power and in vitro scavenging activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion (O2-), and hydroxyl (OH) free radicals. The results revealed that the weight-average relative molecular mass (MW) of HAP-I was 16,861; FT-IR spectra indicated the presence of characteristic absorption peaks of polysaccharides and an amino-group-containing β-D-glucose ring structure in HAP-I. GC results showed that HAP-I contained four monosaccharides, rhamnose (Rha), mannose (Man), glucose (Glu), and galactose (Gal), with a molar ratio of 1:8.29:7.45:18.13. The results from periodate oxidation and Smith degradation revealed that HAP-I had a D-glucopyranose ring containing mannosidase, including α- and β-configurations; the branches of HAP-I were composed of 66.7% (1→3) glycosidic linkages, 22.24% (1→6) and (1→) sugar residues, and 11.06% (1→2) sugar residues (without (1→4) glycosidic linkage). NMR results showed that HAP-I contained galactosyl pyranose with both α- and β-configurations. The in vitro antioxidant activity test suggested that HAP-I had strong scavenging activities on DPPH, O2-, and OH radicals, as well as strong reducing power.