沙棘籽原花色素组成和结构的研究

采用高效液相色谱-电喷雾串联质谱技术分析鉴定沙棘籽原花色素单体和寡聚体组分,采用Sephadex LH-20柱色谱按聚合度大小对沙棘籽多聚体组分进行分级,并通过苄硫醇酸降解反应(简称硫解)对各分级组分的组成结构特征进行分析.共检测到4种单体和8种二聚体:4种单体分别为儿茶素、表儿茶素、棓儿茶素和表棓儿茶素;二聚体包括3种原花青素二聚体、1种原飞燕草素二聚体和4种混合二聚体.并根据ESI提供的质谱信息,分析确定了混合二聚体组成单元的连接顺序.棓儿茶素是构成多聚体各分级组分末端单元的主要组成成分,棓儿茶素和表棓儿茶素(合并计算)是构成各分级组分延伸单元的主要组成成分;平均聚合度为9.1、13.2和17.0,原飞燕草素比例为69.2%、84.6%、87.4%的三个分级组分是多聚体的主要成分,占多聚体总量的74.7%.

Study on Composition and Structure of Proanthocyanidins from Sea Buckthorn (Hippophae rhamnoides) Seeds

The monomeric and oligomeric proanthocyanidin fractions were analyzed by HPLC-ESI-MASS assay. The polymeric proanthocyanidins were fractionated by Sephadex LH-20 column chromatograph and their chemical constitution were also studied by acid-catalysed degradation in the presence of benzyl mercaptan. Four monomers were identified as catechin, epicatechin, gallocatechin and epigallocatechin. Eight dimers including three dimeric procyanidins, one dimeric prodelphinidin and four mixed dimers were detected and their structures were partly elucidated by the detection of the pseudomolecular ions and main ion fragmentations. The results also showed that the polymers are highly heterogenous, with catechin, epicatechin, gallocatechin and epigallocatechin all being constituent components of both the extension as well as the terminal units. The extension units are mainly gallocatechin, whereas terminal units are mainly gallocatechin and epigallocatechin for all fractions. The polymeric fractions with mDP 9.1, 13.2 and 17.0 represent the three maj or polymeric fractions accountingfor 74.7% of total polymers.