Comparison of the constituents of Apocynum venetum and acidified Apocynum venetum by liquid chromatography–UV diode array detection–electrospray ionisation mass spectrometry

Abstract

A liquid chromatography–electrospray ionization mass spectrometry (LC–ESI-MS) method was developed for the analysis and identification of constituents in plant extracts from the leaves of Apocynum venetum (AV) and acidified A. venetum (AAV). The content of the compounds in AV or its acidified product was found to be variable qualitatively and highly quantitatively. Seventeen major compounds were separated and identified from AV and AAV (Table 1). The identification of the constituents (compounds 1, 3, 5–7, 9–17) in the AV and AAV extracts was based on matching their LC retention time, UV spectrum and the detection of the molecular ions and the fragment ions of the compounds obtained from MS/MS experiments with those of authentic standards and data reported in the literature. The main difference between AV and AAV is that the extract of AV contains high level of quercetin-3-O-β-d-glucosyl-β-d-glucopyranosides, quercetin-3-O-glucuronide, quercetin-3-O-rutinoside, quercetin-3-O-glucoside, acetylated quercetin-3-O-galactoside, biapigenin and adhyperforin, while that of AAV had high contents of quercetin-3-O-galactoside, kaempferol-3-O-galactoside, amentoflavone and adhyperforin, which are the main constituents to differentiate AV and AAV. Table 1 Major compound in extracts of AV and AAV Compound Structure R1 R2 MF MW Quercetin-3-O-β-d-glucosyl-β-d-glucopyranosides Open image in new window O-Maltose OH C27H30O17 626 Quercetin-3-O-glucuronide O-Glucuronide OH C21H18O13 478 Quercetin-3-O-rutinoside O-Rutinose OH C27H30O16 610 Quercetin-3-O-glucoside O-Glucose OH C21H20O12 464 Quercetin-3-O-galactoside O-Galactose OH C21H20O12 464 Quercetin-3-O-arabinofuranoside O-Arabinofuranose OH C20H18O11 434 Ac-quercetin-3-O-glucoside O-Open image in new window OH C23H22O13 506 Ac-quercetin-3-O-galactoside O-Open image in new window OH C23H22O13 506 Kaempferol-3-O-glucoside O-Glucose H C21H20O11 448 Kaempferol-3-O-galactoside O-Galactose H C21H20O11 448 Quercetin OH OH C15H10O7 302 Kaempferol OH H C15H10O6 286 Compound Structure MF MW Biapigenin Open image in new window C30H18O10 538 Amentoflavone Open image in new window C30H18O10 538 Compound Structure R MF MW Hyperforin Open image in new window CH3 C34H64O4 536 Adhyperforin CH2CH3 C35H66O4 550