Awantika Singh1,2, Sunil Kumar1, Vikas Bajpai1,2, T Jagadeshwar Reddy1,2, K B Rameshkumar3, Brijesh Kumar1,2. 1. Sophisticated Analytical Instrument Facility Division, CSIR - Central Drug Research Institute, Lucknow, 226031, India. 2. Academy of Scientific and Innovative Research, New Delhi, 110001, India. 3. Phytochemistry and Phytopharmacology Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Palode, Thiruvananthapuram, 695562, Kerala, India.
Abstract
RATIONALE: 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.
RATIONALE: 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-Cglycosides; 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.