Activity guided isolation of isoflavones and hyphenated HPLC-PDA-ESI-ToF-MS metabolome profiling of Azorella madreporica Clos. from northern Chile

Abstract

Four isoflavones were isolated from the MeOH extract of a sample of Azorella madreporica from the high Andes of northern Chile by selective fractionation using the bleaching of the DPPH radical. The compounds were identified by NMR spectroscopy and mass spectrometry together with 18 additional complex isoflavones present in the plant extract which were detected for the first time using HPLC hyphenated with UV–visible and high resolution mass detectors (HR-PDA-ToF-ESI-MS). The results obtained showed that the methodology developed is appropriate for rapid analysis and identification of isoflavones in extracts from native A. madreporica which can have potential use as an additive for food, or as a nutritional supplement due to the high content on isoflavones (yield of 162.98, 290.18, 44.25 and 31.03mg/kg dry plant for the isolated compounds genistein-8-C-β-d-glucopyranoside (1), alpinum isoflavone (19), angustone C (21) and 4´-acetyl-alpinum isoflavone, 22, respectively). The latter compound 22 is a new isoflavone derivative isolated for the first time from a plant source. The moderate antioxidant properties and content of isoflavonoids found in the aerial parts can explain, at least in part, the traditional use of the native plant and health benefits of the infusions.