Identification of flavonoids in Plumula nelumbinis and evaluation of their antioxidant properties from different habitats

Abstract Plumula nelumbinis is a well-known functional food and traditional medicine. In this study, a sensitive and efficient ultra-performance liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS) method was used for systematic identification of the total flavonoids in Plumula nelumbinis . Based on comparisons of retention times, mass spectrometry data and molecular weights with standards and references, thirty-eight flavonoid compounds were unambiguously or tentatively identified. Ten flavonoids were detected for the first time in Nelumbo and fifteen flavonoids were detected for the first time in Plumula nelumbinis . The study revealed a positive correlation between total flavonoids and the results of the antioxidant activity determinations which were accomplished with 1,1-diphenyl-2-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC) and ferric reducing ability of plasma (FRAP) assays. In 13 Chinese habitats that were examined for the first time, the content of flavonoids varied from 44.51 ± 0.58 to 117.82 ± 0.35 μg RE/mg DW. Among of them, Hunanxiangtan and Shandongheze provinces produce plants with the highest content of flavonoids, and also exhibiting the strongest antioxidant activity measured in the three assays. These two habitats could therefore have advantages over other habitats. This study applies rational and effective utilities to the analysis of Plumula nelumbinis samples from different habitats and allows their evaluation as natural medicines or functional food materials in commercial processing.