Phyllostachys edulis (PES), the most important bamboo species in China, is widely distributed in East Asia. Flavonoids, which are important bioactive natural compounds, often have similar structures, making their structural elucidation difficult. The aim of this study was to represent valuable, reliable mass spectral data for the identification of flavonoids in plant leaves. Ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC–Q-TOF-MS/MS) method was established for characterization and identification of the major flavonoids in PES leaf extract. A total of 13 flavonoids were simultaneously characterized, and their proposed characteristic product ions and fragmentation pathways were investigated. Thirteen compounds were separated on an Agilent Zorbax RRHD SB-C18 column (150 mm × 2.1 mm, 1.8 μm). On the basis of comparing with the 4 reference standards and the literature data, the other 9 flavonoids were identified by tandem mass spectrometry (MS/MS). Eight compounds (compounds 1, 4, 5, 8, 9, 10, 11, and 12) were found in PES leaves for the first time. An efficient UPLC–QTOF-MS/MS method was successfully applied for the structural identification of flavonoids in PES leaves. These results have practical applications for the rapid identification and structural characterization of these compounds in crude bioactive extracts or mixtures.

Bamboo leaves extract (BLE) has a variety of physiological functions such as antitumour, anti-inflammatory, antioxidant and blood fat reduction activities and the flavonoids of bamboo leaves are the major active constituents. To profile the flavonoids in the complex BLE, a rapid and sensitive analytical method based on ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) was developed for the structural identification of the flavonoids in Bambusa chungii leaves extract using accurate mass measurements and characteristic fragmentation patterns. After separation on an Agilent SB-C18 Rapid Resolution High Definition (RRHD) column (2.1 mm × 150 mm, 1.8 μm) by gradient elution with 0.1% formic acid aqueous solution and acetonitrile as the mobile phase, the sample was analysed by ESI-QTOF-MS/MS in the negative mode. A total of 22 flavonoids were detected, and eight of these were identified by comparison with reference standards, while the other fourteen were tentatively identified according to their MS/MS data. The main fragmentation pathways of flavonoid C-glycosides (compounds 1, 5 and 10), flavonoid di-C,O-glycosides (compound 4), flavonoid di-C-glycosides (compound 7) and flavonoid C,O-di-glycosides (compounds 2 and 14) are shown in this article. This is the first report on the analysis of the flavonoids in the extract of B. chungii leaves. The present work demonstrates that UPLC-ESI-Q-TOF-MS/MS is an efficient technique for identifying multiple flavonoids of BLE.

Bamboo juice is a traditional Chinese drink and herbal medicine, and bamboo juice oral liquids are widely sold for the treatment of cough and phlegm in China. In this study, 26 main compounds of bamboo juice (Phyllostachys edulis) were separated, precisely identified, and qualitative analysis using NMR (nuclear magnetic resonance) and quantitative analysis using UPLC-Q-TOF-MS (ultra-performance liquid chromatography with high-resolution quadrupole time-of-flight mass spectrometer), respectively. Potentially harmful levels of added excessive preservatives, including benzoic acid, ethylparaben, and sorbic acid, were found in bamboo juice oral liquid. Carbohydrates were determined to be the major components of bamboo juice, with contents as high as 191.13 g L−1, far higher than those of other compounds. The result indicated that the cough relief activity of bamboo juice oral liquid may be related to their high levels of added preservatives.