Structural characterization and identification of oleanane-type triterpene saponins in Glycyrrhiza uralensis Fischer by rapid-resolution liquid chromatography coupled with time-of-flight mass spectrometry
Structural characterization and identification of oleanane-type triterpene saponins in Glycyrrhiza uralensis Fischer by rapid-resolution liquid chromatography coupled with time-of-flight mass spectrometry
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DOI：
10.1002/rcm.4768
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发表时间：
2010-11-01
影响因子：
2
通讯作者：
Li, Ping
中科院分区：
文献类型：
--
作者：
Zheng, Yun-Feng;Qi, Lian-Wen;Li, Ping
齐墩果烷型三萜皂苷（OTS）是甘草的主要活性成分。本工作建立了快速分离液相色谱-飞行时间质谱（RRLC/TOF-MS）联用技术，对G.乌拉尔种。首次对13个OTS的主要诊断离子和裂解途径进行了表征。在正离子模式下，在120 V的低碎裂电压下，获得了[M + H]（+）或/和[M + Na]（+）的前体离子，用于分子式的准确测定。当碎裂电压增加到425 V时，观察到丰富的特征碎片离子用于结构表征。糖部分的中性损失，如葡萄糖醛酸（G1 cA，176 Da），葡萄糖（G1 c，162 Da）和鼠李糖（Rha，146 Da），通常在MS光谱中观察到的糖数和序列的预测。其他典型的损失包括来自[糖苷配基+ H H2O]（+）（命名为[B]（+））的AcOH（60 Da）、CH 2 O（30 Da）、2 x H2O（2 x 18 Da）和HCOOH（46 Da），分别对应于糖苷配基部分上存在C-22-乙酰基、C-24-羟基、C-22-羟基或C-30-羧基。特别地，观察到A-和B-环上的糖苷配基部分的特征性环裂解。根据参比化合物的裂解模式，从G. uralensis，其中13个已明确确定，其他6个暂时指定。版权所有（C）2010约翰威利父子有限公司
Oleanane-type triterpene saponins (OTS) are major active ingredients in Glycyrrhiza uralensis. In this work, a rapid-resolution liquid chromatography with time-of-flight mass spectrometry (RRLC/TOF-MS) method has been developed to characterize and identify OTS from G. uralensis. The major diagnostic ions and fragmentation pathways from thirteen OTS have been characterized for the first time. At a low fragmentor voltage of 120 V in positive ion mode, the precursor ion [M + H](+) or/and [M + Na](+) was obtained for accurate determination of molecular formula. When the fragmentor voltage was increased to 425 V, abundant characteristic fragment ions were observed for structural characterization. Neutral losses of sugar moieties, such as glucuronic acid (G1cA, 176 Da), glucose (G1c, 162 Da) and rhamnose (Rha, 146 Da), were commonly observed in the MS spectra for prediction of the sugar number and sequences. Other typical losses included AcOH (60 Da), CH2O (30 Da), 2 x H2O (2 x 18 Da) and HCOOH (46 Da) from [Aglycone + H H2O](+) (named [B](+)), corresponding to the presence of a C-22-acetyl group, C-24-hydroxyl group, C-22-hydroxyl group or C-30-carboxyl group on the aglycone moiety, respectively. In particular, characteristic ring cleavages of the aglycone moieties on A- and B-rings were observed. Based on the fragmentation patterns of reference compounds, nineteen OTS have been identified in an extract of G. uralensis, thirteen of which were unambiguously identified and the other six were tentatively assigned. Copyright (C) 2010 John Wiley & Sons, Ltd.