title: Structural characterization of chromone C-glucosides in a toxic herbal remedy.
abstract: Two novel compounds, 8-C-D-glucopyranosyl-7-hydroxy-5-methylchromone-2-carboxylic acid and a 2-O'-p-coumaroyl derivative thereof, were identified in a herbal tea that caused severe vomiting in a South African patient who had taken the traditional remedy to clean his stomach. For structural characterization, electrospray (ES) ionization in combination with collision-induced dissociation (CID) and tandem mass spectrometry (MS/MS) were used, as well as UV and nuclear magnetic resonance (NMR) spectroscopy. Specific ions or neutral losses generated under conditions of ES-MS/CID/MS permitted the establishment of structural features such as the free carboxyl group, the C-hexosidic part and the p-coumaroyl group. NMR spectroscopy was necessary to support the structure of the chromone-type aglycone and the glucosidic parts. Since the compounds are structurally related to aloesin and aloeresin A, which are chemotaxonomic markers of Aloe species, and have not been previously reported, we propose that they were formed by oxidative degradation during preparation of the herbal tea from an Aloe species or during its storage.
authors.affiliation: University of Antwerp, Department of Pharmaceutical Sciences, Universiteitsplein 1, B-2610 Antwerp, Belgium.
authors.forename: Wu
authors.initials: W
authors.lastname: Wang
authors.forename: Filip
authors.initials: F
authors.lastname: Cuyckens
authors.forename: Hilde
authors.initials: H
authors.lastname: Van den Heuvel
authors.forename: Sandra
authors.initials: S
authors.lastname: Apers
authors.forename: Luc
authors.initials: L
authors.lastname: Pieters
authors.forename: Vanessa
authors.initials: V
authors.lastname: Steenkamp
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stewart
authors.forename: Valerie A
authors.initials: VA
authors.lastname: Luyckx
authors.forename: Magda
authors.initials: M
authors.lastname: Claeys
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002867:Chromones / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D005960:Glucosides / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013058:Mass Spectrometry; D015394:Molecular Structure; D008517:Phytotherapy / Q000009:adverse effects*; D010946:Plants, Medicinal / Q000009:adverse effects* / Q000737:chemistry / Q000378:metabolism; D013019:South Africa; D013662:Tea / Q000737:chemistry* / Q000378:metabolism; D014839:Vomiting / Q000139:chemically induced
chemical_list: D002867:Chromones; D005960:Glucosides; D013662:Tea; C069868:aloesin