Isolation and identification of flavonoids from the roots of Brassica rapa ssp

Abstract

The roots of Brassica rapa ssp. were extracted with 95% aqueous ethanol and the concentrated extracts were partitioned using ethyl acetate (EtOAc), n-butyl alcohol and H2O, successively. From the EtOAc fraction, five flavonoids were isolated through repeated silica gel and octadecyl silica gel (ODS) column chromatography (c.c.). Based on NMR, mass spectrometry (MS) and IR spectroscopic data, the chemical structures of the compounds were determined to be licochalcone A (1), 4,4'-dihydroxy-3'-methoxychalcone (2), liquirtigenin (3), liquiritin (4), and isoliquiritin (5). This is the first report of these compounds isolated from the root of this plant.