海洋多糖的生物活性虽不断被揭示，但海洋多糖类药物种类非常少，我国目前仅有褐藻多糖作为海洋多糖药物在医药领域应用，所以海洋多糖药物的研究具有重要意义。本课题组对坛紫菜纯多糖的前期研究发现其能够抑制肿瘤细胞生长，且抗肿瘤活性与某些特定的寡糖片段有关，但目前对于坛紫菜多糖的研究多集中在制备、整体结构表征和生物效应评价上，对于确切发挥抗肿瘤活性作用的核心结构、构效关系与作用机制尚不明确。针对上述问题，本项目拟通过糖谱法（基于结构特征的多糖定性、定量分析方法）结合抗肿瘤活性评价指标，对酶解后的坛紫菜纯多糖进行筛选得到具有抗肿瘤活性的片段，再对其分离纯化和仪器分析技术解析结构特征，并进行体内外抗肿瘤活性和作用机制研究，探讨坛紫菜多糖抗肿瘤活性核心结构及其构效关系，阐明其作用机制，这将为坛紫菜多糖活性结构分析的深入研究和应用提供实验及理论依据，也将对坛紫菜资源有效开发成多糖类药物产生积极影响。

Although many studies have demonstrated the biological activities and functions of marine polysaccharides in succession, few types of drugs are made of these polysaccharides. In China, only the polysaccharides from brown algae have been used as drugs in the field of medicine. Therefore, it is significant and meaningful to study marine polysaccharide drugs. A preliminary study on the polysaccharide in Porphyra haitanensis proves that this polysaccharide can inhibit the proliferation of tumor cells. Meanwhile, there may be some connections between some specific oligosaccharides and antitumor activities. Currently, studies about the polysaccharide from P. haitanensis, are mainly focused on the sample preparation, integrated structure characterization and biological evaluation. As for the active moiety of polysaccharide that is responsible for the antitumor activities, as well as the structure-function relationship and mechanism of action, no clear conclusion has been made. Aiming at these problems, this project will screen enzymatic fragments which have showed antitumor activities from purified polysaccharide of P. haitanensis by using saccharide mapping (a method based on structure-related qualitative and quantitative analysis of polysaccharide) according to the antitumor activities assay. Subsequently, these fragments will be purified and the instrumental analysis technique will be applied to elucidate their structure. In order to clarify the active moiety of antitumor activities and the mechanism of the structure-function relationship, in-vitro and in-vivo as well as the possible mechanism of antitumor properties will also be examined. This study is expected to set up an experimental and theoretical basis for the research of active moiety of P. haitanensis polysaccharide, and promote the development of the polysaccharide drug from P. haitanensis.