目的：从油柑中提取油柑多糖，并分析其清除氧自由基作用。方法：建立热水提取乙醇沉淀鞣酸除蛋白H₂O₂脱色工艺制备油柑多糖(PePS)，并作了糖及蛋白质含量测定、多糖的特征分析及清除氧自由基活性测定。结果：油柑多糖得率为1.94%。多糖经SephadexG-100柱层析，洗脱峰为一糖峰及一蛋白峰。总糖含量为64.5%％。蛋白质含量为35.0%。红外吸收光谱分析(IR)，具有多糖及蛋白质的特征吸收峰。差示扫描量热分析(DSC)，结果见该多糖除出现117.20℃的特大吸热峰外，尚有三个小吸热峰和一个小放热峰。测定清除·OH自由基活性，其IC₅₀为638μg；清除超氧阴离子自由基(O₂)活性，其IC₅₀为500μg；抑制脂质过氧化(LPO)作用，其IC₅₀为1.25mg。结论：油柑多糖具有清除氧自由基的作用，其活性大小与多糖的用量呈正相关。

OBJECTIVE: To extract the polysaccharide from Phyllanthus emblica L. and analyse its effect of cleaning oxygen radical. METHOD: A technic was found to extract Phyllanthus emblica L. polysaccharide (PePS). Hot water extraction, ethanol sedimentation, tonnic acid deproteinization and H₂O₂decolourization were performed. Tests were also done with the extraction material, including the determination of sugar and protien content, the analysis of polysaccharide behaviour, and the determination of the activities of cleaning oxygen radical. RESULTS: The extraction ratio was 1.94%. With Sephadex G-100 chromatography, the elution peak of the PePS was single sugar peak and also single protein peak. Its total sugar content was 64.5%. Its protein content was 35.0%. IR showed that the absorption peak of sugar and protein. DSC revealed that a super peak of absorption heat at 117.20 ℃ and three low peaks of absorption heat and one low peak of release heat. In the determination of the avtivities of cleaning hydroxid radical, its IC₅₀ was 638μg. In the determination of the activities of cleaning superoxide anion radical, its IC₅₀ was 500μg. In the determination of inhibiting lipid peroxidation, its IC₅₀ was 1.25mg. CONCLUSION: PePS is a kind of proteoglycans. It has the effect of cleaning oxygen radical. Its activities and amounts are relative.