目的 对沙棘Hippophae rhamnoides籽中原花色素寡聚体和多聚体组分进行检测分析。方法 采用高效液相色谱-电喷雾串联质谱技术分析沙棘籽原花色素单体和寡聚体组分,根据ESI提供的质谱信息,确定其主要的结构特征;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。结果 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。平均聚合度为9.1、13.2和17.0。棓儿茶素是构成各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)是构成各组分延伸单元的主要组成成分。结论 沙棘籽原花色素结构和组成显著不同于葡萄籽原花青素,主要为原飞燕草素。

Objective The oligomeric and polymeric proanthocyanidins in different fractions from Hippophae rhamnoides seeds were investigated. Methods The monomeric and oligomeric fractions were analyzed by HPLC/ESI-MASS detection. The polymeric proanthocyanidins were fractionated by Sephadex LH-20 column chromatography and their chemical constructures were studied by acid-catalysed degradation in the presence of benzyl mercaptan. Results Four monomers were identified as catechin, epicatechin, gallocatechin, and epigallocatechin. Eight dimers including three dimeric procyanidins and one dimeric prodelphinidin, and four mixed dimers were detected and their structures were partly elucidated by the detection of the pseudomolecular ion and main ion fragmentations. The results also showed that polymers to be highly heterogenous with catechin, epicatechin, gallocatechin, and epigallocatechin all being components of both the extension and the terminal units. The extension units were mainly gallocatechin, whereas the terminal units were mainly gallocatechin and epigallocatechin for all fractions. The proanthocyanidins with a mean degree of polymerization (mDP) of 9.1, 13.2 and 17.0 represented the three major polymeric fractions. Conclusion Proanthocyanidins of H. rhamnoides seeds, predominantly being of prodelphinidin-type, are remarkably different from that of grape seeds.