Characterization and quantification of flavonoids and saponins in adzuki bean (Vigna angularis L.) by HPLC–DAD–ESI–MSn analysis

BACKGROUND Bioactive activities of adzuki bean have been widely reported, however, the phytochemical information of adzuki bean is incomplete. The aim of this study was to characterize and quantify flavonoids and saponins in adzuki bean. High performance liquid chromatography with diode array detection and electro spray ionization-tandem multi-stage mass spectrometry (HPLC-DAD-ESI-MSn) were applied to do qualitative and quantitative analyses. RESULTS A total of 15 compounds from adzuki bean were identified by HPLC-DAD-ESI-MSn. Among 15 compounds identified, four flavonoids (catechin, vitexin-4″-O-glucoside, quercetin-3-O-glucoside, and quercetin-3-O-rutinoside) and six saponins (azukisaponin I, II, III, IV, V, and VI) in adzuki bean were further quantified by external calibration method using HPLC-MS with the program of time segment and extract ion chromatogram (EIC) analysis. CONCLUSIONS Current qualitative and quantitative method based on HPLC and MS technique provides a scientific basis for in vitro and in vivo pharmacological study in the future. Graphical abstract Isolation and characterization of flavonoids and saponins from adzuki bean.