title: Systematic identification and quantification of tetracyclic monoterpenoid oxindole alkaloids in Uncaria rhynchophylla and their fragmentations in Q-TOF-MS spectra.
abstract: Uncaria rhynchophylla (UR) is a species of Uncaria that is distributed mainly in China and Japan. In this study, the chemical constituents, including alkaloids, flavonoids, and quinic acids, in UR have been systematically identified and quantified by a developed method of high-performance liquid chromatography coupled with diode-array detection and quadrupole time-of-flight mass spectrometry (Q-TOF-MS). Tetracyclic monoterpenoid oxindole alkaloids (TMOAs) are characteristic compounds in this herb, and their fragmentations in Q-TOF-MS have been investigated. Diagnostic fragmentation ions (DFIs) were first delineated for isorhynchophylline-type (7S, C20-ethyl) and corynoxeine-type (7R, C20-vinyl) TMOAs, and these were used for identification of these alkaloids in UR. In this study, a total of 29 compounds, comprising 18 alkaloids, six flavonoids, and five quinic acids, were identified. Among them, there are four novel TMOAs, named as 22-O-β-glucopyranosyl isorhynchophyllic acid (10), 22-O-β-glucopyranosyl rhynchophyllic acid (11), 9-hydroxy isocorynoxeine (16), and 9-hydroxy corynoxeine (20), which have not been reported previously. Furthermore, eight marker compounds, namely chlorogenic acid (3), catechin (8), epicatechin (9), isocorynoxeine (24), rhynchophylline (25), isorhynchophylline (27), vincoside lactam (28), and corynoxeine (29), have been simultaneously quantified. The developed method has been validated and successfully applied to analyze three samples of UR from Jiangxi Province. The contents of the marker compounds have been detected and compared.
authors.affiliation: Department of Pharmaceutical Analysis, China Pharmaceutical University, Nanjing, China.
authors.forename: Shuanglu
authors.initials: S
authors.lastname: Xie
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Shi
authors.forename: Yixiang
authors.initials: Y
authors.lastname: Wang
authors.forename: Chunyong
authors.initials: C
authors.lastname: Wu
authors.forename: Wenyuan
authors.initials: W
authors.lastname: Liu
authors.forename: Feng
authors.initials: F
authors.lastname: Feng
authors.forename: Ning
authors.initials: N
authors.lastname: Xie
mesh_terms: D002681:China; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005419:Flavonoids / Q000032:analysis / Q000302:isolation & purification; D026121:Indole Alkaloids / Q000032:analysis* / Q000302:isolation & purification; D013058:Mass Spectrometry / Q000379:methods*; D011801:Quinic Acid / Q000032:analysis / Q000302:isolation & purification; D032070:Uncaria / Q000737:chemistry*
chemical_list: D005419:Flavonoids; D026121:Indole Alkaloids; D011801:Quinic Acid