Ge Yue-Wei, Zhu Shu, Kazuma Kohei, Wei Sheng-Li, Yoshimatsu Kayo, Komatsu Katsuko
Division of Pharmacognosy, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
Division of Kampo-Pharmaceutics, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
Anal Bioanal Chem. 2016 May;408(13):3555-70. doi: 10.1007/s00216-016-9433-z. Epub 2016 Mar 1.
Proanthocyanidins (PAs) are major anti-diarrhea constituents in rhubarb, one of the frequently used traditional medicines. However, the phytochemical investigation of PAs in rhubarb was hampered by their strenuous purification and identification. In the present study, aiming to clarify the distribution of PAs in different rhubarb species, a molecular ion index was priorly established according to the structural features of B-type PAs, which led to a series of targeted discovery of oligomeric PAs in rhubarb by the HPLC-ESI-MS/MS method. Totally, 66 oligomeric PAs including 27 dimers, 29 trimers, and 10 tetramers were tentatively identified on the basis of their MS/MS spectra from 28 rhubarb samples derived from 5 Rheum species as R. palmatum, R. tanguticum, R. officinale, R. coreanum, and R. laciniatum. It is noteworthy that 6 propelargonidins, 14 prodelphinidins, and 10 procyanidin-tetramers were identified from rhubarb for the first time. The profiling comparison of these oligomeric PAs in different rhubarb samples was achieved by visualizing their abundance in a heat map, which indicated the dominant PAs in rhubarb were procyanidin-dimer and its galloylated derivatives.
原花青素（PAs）是大黄（常用传统药物之一）中的主要止泻成分。然而，大黄中PAs的植物化学研究因其纯化和鉴定困难而受到阻碍。在本研究中，为了阐明PAs在不同大黄品种中的分布，根据B型PAs的结构特征预先建立了分子离子指数，这使得通过HPLC-ESI-MS/MS方法在大黄中一系列靶向发现了低聚PAs。基于来自5种大黄属植物（掌叶大黄、唐古特大黄、药用大黄、朝鲜大黄和鸡爪大黄）的28个大黄样品的MS/MS光谱，初步鉴定出总共66种低聚PAs，包括27种二聚体、29种三聚体和10种四聚体。值得注意的是，首次从大黄中鉴定出6种原天竺葵色素、14种原飞燕草色素和10种原花青素四聚体。通过在热图中可视化它们的丰度，实现了不同大黄样品中这些低聚PAs的谱图比较，这表明大黄中占主导地位的PAs是原花青素二聚体及其没食子酰化衍生物。
