Screening and Identification of Antioxidants in Glycyrrhiza Extract Rich in Glycyrrhizine by High Performance Liquid Chromatography Coupled with Post Column DPPH Assay

A new method based on HPLC online scavenging DPPH radical activity and HPLC-MS/MS method for the identification of antioxidants from glycyrrhiza extract rich in glycyrrhizine was developed.The glycyrrhiza extract was separated by HPLC and the outlet of HPLC photo diode array detector flow cell was connected to a DPPH flow.Antioxidants were reacted with DPPH in post-column reaction coil and monitored by UV detector at 517 nm.The results showed that eight compounds with scavenging radical activity were found in the glycyrrhiza extract,which were identified as formononetin,choerospondin,apioliquiritin,liquiritigenin,liquiritin,echinatin,glyyunnansapogenin F,glabrone and licochalcone C by MS/MS and UV spectrometry.