中文摘要：

粗老绿茶经弱碱性的大孔阴离子交换树脂D315柱层析分级，得到以酸性糖为主的多糖样品ATPS。将ATPS与金属离子Ca^2＋、Fe^3＋络合，制备得到ATPS-Ca（Ⅱ），ATPS—Fe（Ⅲ）络合物。研究发现茶多糖对不同的金属离子配位能力大小不同，ATPS-Ca（Ⅱ）的络合程度远高于ATPS-Fe（Ⅲ）。红外光谱扫描发现茶多糖可能以仲羟基和羧基的C—O配位为主。采用化学发光体系产生自由基模型，以比较经金属离子络合后的不同结构的茶多糖清除自由基的能力。研究发现：ATPS及其络合物清除·OH活性远高于O2^-＋，且ATPS—Ca（Ⅱ）清除羟自由基活性比ATPS减弱很多，ATPS—Fe（Ⅲ）清除羟自由基活性与ATPS接近，一方面，这可能与茶多糖ATPS与二价钙的络合程度远远强于与三价铁的络合程度，其清除·OH活性很大程度与络合金属离子位点的数目及络合强度有关，另一方面，可能与·OH相比，茶多糖与O2^-＋的反应活性很弱有关。

英文摘要：

A kind of tea polysaccharides, coded as ATPS,which was mainly acid polysaccharides were obtained from the coarse green tea which was purified by anion exchange resin D315. ATlaS formed metal complexes when chelated with Fe^3 ＋ and Ca^2 ＋. It showed that the coordination degrees was different in which the amount of ATPS-Ca（Ⅱ） complex was much more than that of ATPS-Fe（ Ⅲ ）. FT-IR scan showed that ATPS was mainly composed of secondary hydroxyl and carboxyl by the way of C-O coordination. The chemiluminescence（CL） method was used to investigate the free radical scavenging activity of the polysaceharides with different structures. It showed that the HO ·scavenging activities of ATPS and its complexes were much more than the O2^-＋ scavenging activities. HO · scavenging activity of ATPS-Ca（ Ⅱ ） was much weaker than ATPS,but that of ATPS-Fe（ Ⅲ ） had almost the same with ATPS. On the one hand ,this might be that the chelating degrees of ATPS with Ca^2 ＋ was much more that that with Fe^3 ＋ and HO · scavenging activities was probably related with the number and occupation of the positions for chelating metal ions ; on the other hand, this might be concerned with the less activities of tea polysaccharides reacted with O2^-＋ .