Rapid identification of new minor chemical constituents from Smilacis Glabrae Rhizoma by combined use of UHPLC-Q-TOF-MS, preparative HPLC and UHPLC-SPE-NMR-MS techniques

IntroductionHerbs are an important resource for new drug development. However, the conventional approach for the discovery of new compounds from herbs was time-consuming, tedious, and inefficient. ObjectivesEstablish a quick approach to identify new minor constituents in herbs. MethodsThe constituents in herbs were firstly analysed using ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). Based on the accurate masses, isotopic ions, and the characteristic fragmentation ions in the mass spectra, the molecular compositions and possible structures of compounds were first deduced. After being enriched by a preparative HPLC method, the potential new minor structures were definitely identified by an on-line UHPLC-solid phase extraction-nuclear magnetic resonance-mass spectrometry (UHPLC-SPE-NMR-MS) approach. ResultsBy combined the use of UHPLC-Q-TOF-MS, preparative HPLC and UHPLC-SPE-NMR, three new minor compounds were definitely identified as bis-3,4-dihydroxyphenylpropanoid-substituted catechins (A2 and A3) and 4-formyl-astilbin (B5). In addition, five isomers of bis-dihydroxyphenylpropanoid-substituted catechin (A1, A4-A7), four isomers of 4-formyl-astilbin (B1-B4), engeletin formates and isomers (C1-C5), formyl-cinchonains (D1-D4), formyl-caffeoylshikimic acid (E1-E4) were also tentatively determined by MS and MS/MS characterisation. ConclusionThe combination of UHPLC-Q-TOF-MS, preparative HPLC and UHPLC-SPE-NMR-MS techniques is a quick and effective approach for finding new minor constitutes from herbs. Copyright (c) 2015 John Wiley & Sons, Ltd. A combined use of UHPLC-Q-TOF-MS, preparative HPLC and UHPLC-SPE-NMR approach was applied to quickly determine new minor constituents in plant. Twenty-five new minor compounds were detected from Smilacis Glabrae Rhizoma. Bis-phenylpropanoid-substituted catechins, astilbin formates, engeletin formates, formyl-cinchonains, formyl-caffeoylshikimic acids were identified for the first time.