title: An enhanced targeted identification strategy for the selective identification of flavonoid O-glycosides from Carthamus tinctorius by integrating offline two-dimensional liquid chromatography/linear ion-trap-Orbitrap mass spectrometry, high-resolution diagnostic product ions/neutral loss filtering and liquid chromatography-solid phase extraction-nuclear magnetic resonance.
abstract: Targeted identification of potentially bioactive molecules from herbal medicines is often stymied by the insufficient chromatographic separation, ubiquitous matrix interference, and pervasive isomerism. An enhanced targeted identification strategy is presented and validated by the selective identification of flavonoid O-glycosides (FOGs) from Carthamus tinctorius. It consists of four steps: (i) enhanced separation and detection by offline two-dimensional liquid chromatography/LTQ-Orbitrap MS (offline 2D-LC/LTQ-Orbitrap MS) using collision-induced dissociation (CID) and high-energy C-trap dissociation (HCD); (ii) improved identification of the major aglycones by acid hydrolysis and LC-SPE-NMR; (iii) simplified spectral elucidation by high-resolution diagnostic product ions/neutral loss filtering; and (iv) more convincing structural identification by matching an in-house library. An offline 2D-LC system configuring an Acchrom XAmide column and a BEH Shield RP-18 UPLC®column enabled much better separation of the easily co-eluting components. Combined use of CID and HCD could produce complementary fragmentation information. The intensity ratios of the aglycone ion species ([Y0-H]-/Y0-and [Y0-2H]-/Y0-) in the HCD-MS2spectra were found diagnostic for discriminating the aglycone subtypes and characterizing the glycosylation patterns. Five aglycone structures (kaempferol, 6-hydroxykaempferol, 6-methoxykaempferol, carthamidin, and isocarthamidin) were identified based on the1H-NMR data recorded by LC-SPE-NMR. Of the 107 characterized flavonoids, 80 FOGs were first reported from C. tinctorius. Unknown aglycones, pentose, and novel acyl substituents were discovered. A new compound thereof was isolated and fully identified, which could partially validate the MS-oriented identification. This integral strategy can improve the potency, efficiency, and accuracy in the detection of new compounds from medicinal herbs and other natural sources.
authors.affiliation: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China; University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China.
authors.forename: Chang-Liang
authors.initials: CL
authors.lastname: Yao
authors.affiliation: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.
authors.forename: Wen-Zhi
authors.initials: WZ
authors.lastname: Yang
authors.affiliation: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Si
authors.affiliation: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Analytical Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
authors.forename: Nai-Xia
authors.initials: NX
authors.lastname: Zhang
authors.affiliation: Department of Analytical Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
authors.forename: Hua-Li
authors.initials: HL
authors.lastname: Chen
authors.affiliation: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China; University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China.
authors.forename: Hui-Qin
authors.initials: HQ
authors.lastname: Pan
authors.affiliation: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.affiliation: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China. Electronic address: wanyingwu@simm.ac.cn.
authors.forename: Wan-Ying
authors.initials: WY
authors.lastname: Wu
authors.affiliation: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China. Electronic address: daguo@simm.ac.cn.
authors.forename: De-An
authors.initials: DA
authors.lastname: Guo
mesh_terms: D031187:Carthamus tinctorius / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods*; D005419:Flavonoids / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D006027:Glycosides / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry / Q000379:methods*; D052616:Solid Phase Extraction
chemical_list: D005419:Flavonoids; D006027:Glycosides
keywords: Carthamus tinctorius; Diagnostic product ions filtering; Enhanced targeted identification strategy; Flavonoid O-glycoside; Liquid chromatography-solid phase extraction-nuclear magnetic resonance; Offline two-dimensional liquid chromatography