ABSTRACT
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.
ABSTRACT
OBJECTIVE: To establish the HPLC fingerprints of flavone C-glycosides in Dendrobium officinale leaves and determine the content of apigenin-6-C-α-L-arabinoside-8-C-β-D-xyloside for the quality control. METHODS: The compounds were separated by using XB C18(4.6 mm × 250 mm, 5 μm) analytical column. The mobile phase consisted of methanol and water containing 0.4% formic acid. Gradient elution program was used. The detection wavelength was 335 nm. In total 14 batches of Dendrobium officinale leaves and 3 batches of different species from Dendrobium were analyzed. Similarity evaluation system for chromatographic fingerprint of traditional Chinese medicine (2004AB) and principal component analysis(PCA) were used in data analysis. RESULTS: The HPLC fingerprint of flavone C-glycosides of Dendrobium officinale leaves was established. In total 9 peaks were selected as the characteristic common peaks and 8 of them were identified. There were significant differences in the fingerprint chromatograms between Dendrobium officinale leaves and different species from Dendrobium. Principal component analysis showed that apigenin-6-C-α-L-arabinoside-8-C-β-D-xyloside among the flavone di-C-glycosides was the most important component. CONCLUSION The HPLC fingerprint and content of major component can be applied for identification and quality control of Dendrobium officinale leaves.