title: Structural characterization of flavonoid C- and O-glycosides in an extract of Adhatoda vasica leaves by liquid chromatography with quadrupole time-of-flight mass spectrometry.
abstract: BACKGROUND
  Adhatoda vasica Nees is a well-known Ayurvedic medicinal plant, belonging to the family Acanthaceae. This study aims to seek identification and characterization of flavonoid C- and O-glycosides in the aqueous fraction of the plant leaves.
  
  
  METHODS
  A method was developed for simultaneous characterization of flavonoids and their glycosides using high-pressure liquid chromatography with quadrupole time-of-flight mass spectrometry (HPLC/ESI-QTOF-MS/MS). The chromatographic separation was carried on an Agilent Poroshell 120 EC-C18 column (4.6 × 150 mm, 2.7 µm) operated with 0.1% formic acid aqueous solution and methanol as the mobile phase.
  
  
  RESULTS
  The fragmentations of the studied [M-H](-) ions of C-glycosides were shown to be cross-ring cleavages of the glycoside moiety [M-H-(60/90/120)](-) whereas O-glycosides were shown to eliminate the sugar moiety (Y0 (-) or [Y0 -H](-) ) from the aglycone unit; 6-C-glycosides exhibited [M-H-18](-) , a characteristic ion, and also a higher abundance of (0,3) X6 or 8 ions in comparison to 8-C glycosides; flavonoid 6,8-di-C-glycosides exhibited cross-ring cleavages of the sugar attached to the C-6 position preferentially.
  
  
  CONCLUSIONS
  This method was successfully applied for analysis of flavonoids and their glycosides in Adhatoda vasica leaves. A total of 29 compounds were tentatively identified including 17 C-, nine O-glycosides and three flavonoids.
authors.affiliation: Sophisticated Analytical Instrument Facility Division, CSIR - Central Drug Research Institute, Lucknow, 226031, India.|Academy of Scientific and Innovative Research, New Delhi, 110001, India.
authors.forename: Awantika
authors.initials: A
authors.lastname: Singh
authors.affiliation: Sophisticated Analytical Instrument Facility Division, CSIR - Central Drug Research Institute, Lucknow, 226031, India.
authors.forename: Sunil
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Sophisticated Analytical Instrument Facility Division, CSIR - Central Drug Research Institute, Lucknow, 226031, India.|Academy of Scientific and Innovative Research, New Delhi, 110001, India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Bajpai
authors.affiliation: Sophisticated Analytical Instrument Facility Division, CSIR - Central Drug Research Institute, Lucknow, 226031, India.|Academy of Scientific and Innovative Research, New Delhi, 110001, India.
authors.forename: T Jagadeshwar
authors.initials: TJ
authors.lastname: Reddy
authors.affiliation: Phytochemistry and Phytopharmacology Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Palode, Thiruvananthapuram, 695562, Kerala, India.
authors.forename: K B
authors.initials: KB
authors.lastname: Rameshkumar
authors.affiliation: Sophisticated Analytical Instrument Facility Division, CSIR - Central Drug Research Institute, Lucknow, 226031, India.|Academy of Scientific and Innovative Research, New Delhi, 110001, India.
authors.forename: Brijesh
authors.initials: B
authors.lastname: Kumar
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005419:Flavonoids / Q000032:analysis* / Q000737:chemistry; D006027:Glycosides / Q000032:analysis* / Q000737:chemistry; D027902:Justicia / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D005419:Flavonoids; D006027:Glycosides