RESUMO
Millettia nitida var.hirsutissima is a Chinese herbal medicine used for the treatment of gynecological diseases.An HPLC/DAD/ESI-MSn method was established for the rapid separation and characterization of bioactive flavonoids in M.nitida var.hirsutissima.A total of 32 flavonoids were detected,of which 14 compounds were unambiguously characterized by comparing their retention time,UV,and MS spectra with those of the reference standards,and the others were tentatively identified based on their tandem mass spectrometry fragmentation data obtained in the negative ionization mode on line.Nineteen of these compounds characterized were reported from this plant for the first time.
RESUMO
OBJECTIVE: To identify flavone C-glycosides in Dendrobium officinale leaves by high performance liquid chromatography with DAD and electrospray ionization mass spectrometry (HPLC-DAD-ESI-MSn). METHODS: The chromatographic separation was carried out at 30°C on a XB C18 column (4.6 mm × 250 mm, 5 μm) eluted with gradient program. The mobile phase consisted of methanol and water containing 0.4% formic acid. The detection wavelength was 335 nm and the on-line UV spectra was recorded in the range of 190-400 nm. The mass spectra was obtained by Agilent ion trap mass spectrometer in the negative ion mode with capillary voltage 4 500 V, dry gas temperature 350°C, dry gas flow 12.0 L · min-1, nebulizer pressure 241 kPa; mass range recorded m/z 50-600. RESULTS: Eight flavone di-C-glycosides from D. officinale leaves, whose aglycone was apigenin and monosaccharide was connected with C-6 and C-8, were identified by HPLC-DAD-ESI-MSn for the first time. The study further proved the characteristics of fragmentation pattern of flavone C-glycosides in ESI-MSn. CONCLUSION: The method is simple and rapid for the identification of D. officinale leaves. The characteristics of fragmentation pattern of ESI-MSn in flavone di-C-glycosides provide a reference for rapid detection and identification of flavone C-glycosides.