该研究以藏柳茶为原料，用聚乙二醇-超声酶法辅助提取其粗多糖，采用响应面法优化其提取工艺参数。进一步用高效凝胶渗透色谱（HPGPC）、高效液相色谱（HPLC）、红外光谱（FT-IR）和扫描电镜（SEM）对藏柳茶多糖（SAPs）的结构进行初步解析，并考察其抗氧化活性。聚乙二醇-超声酶法辅助提取SAPs的最佳工艺参数为：PEG-400浓度为30%、酶添加量2%（m/m）、pH值4.0、超声功率80%、超声时间2.0 h、超声温度80 ℃。此条件下，藏柳茶多糖提取率为10.95%。经HPLC分析，SAPs主要由半乳糖（13.34%）、葡萄糖（46.76%）、鼠李糖（8.78%）、果糖（2.89%）和阿拉伯糖（11.79%）组成；FT-IR及SEM分析表明，SAPs是一种β-糖苷键的吡喃型非晶态多糖结构。此外，SAPs体外抗氧化活性结果表明其DPPH·清除能力、·OH清除能力和·O2-清除能力的IC50值分别为0.42、2.08、0.28 mg/mL，且随着多糖含量的提高，其自由基清除能力提高，呈现剂量效应关系。所得提取工艺设计空间稳定可行，为藏柳茶多糖提取和产品的综合开发利用提供理论技术支持依据。

Crude polysaccharides from Sibiraea angustata as the raw material were extracted using the polyethylene glycol–ultrasonic enzymatic method, and the extraction process parameters were optimized using response surface methodology. Furthermore, high-performance gel-permeation chromatography (HPGPC), high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) were used to characterize the structure of S. angustata polysaccharides (SAPs) and investigate their antioxidant activity. The optimal process parameters for SAP extraction assisted by the polyethylene glycol–ultrasonic enzymatic method were as follows: 30% PEG-400 concentration, 2% enzyme addition, pH 4.0, 80% ultrasonic power, 2 h ultrasonic treatment duration, and 80 °C ultrasonic treatment temperature. Under these conditions, the extraction rate of polysaccharides was 10.95%. HPLC showed that the SAPs were mainly composed of galactose (13.34%), glucose (46.76%), rhamnose (8.78%), fructose (2.89%), and arabinose (11.79%). FT-IR and SEM revealed that SAPs are pyrenoid amorphous polysaccharide structures with β-glycosidic bonds. In addition, analysis of the in vitro antioxidant activity of SAPs showed that the free radical scavenging ability increased with polysaccharide content in a dose-dependent manner. The IC50 values for DPPH, OH, and O2- free radicals were 0.42, 2.08, and 0.28 mg/mL, respectively. The optimized extraction process is stable and feasible, providing a theoretical and technical basis for the extraction of SAPs from S. angustata and the comprehensive development and utilization of these products.

中央高校基本科研业务费资助项目（31920220024；31920210001）；西北民族大学本科生创新项目（XBMU21139）；中央高校基本科研业务费专项资金资助研究生项目（Yxm-2021073）