Isolation and Identification of Phenolic Glycosides from Panzeria Alashanica Kupr. and Evaluation of Their Antioxidant Activities in Vitro

OBJECTIVE To isolate and identify the antioxidant components from Panzeria alashanica Kupr.. METHODS Panzeria alashanica Kupr. was degrease by dichloromethane with reflux, then the residue was extracted with ethyl acetate to obtain its extract. The ethyl acetate extract was separated by silica gel, Sephadex gel column chromatography and HPLC. The structures of the compounds were determined by spectral data analysis. At the same time, the antioxidant activity of the compounds was determined by DPPH method. RESULTS Four phenolic glycosides were isolated from the ethyl acetate extract of Panzeria alashanica Kupr., namely verbascoside(1), 5,7,4'-trihydroxyflavone-7-O-(6″-O-E-coumaroyl)-β-glucopyranoside(2), 5,7,4'-trihydroxyflavone-7-O-(6″-O-E-caffeyl)-β-glucopyranoside(3) and 5,7,4'-trihydroxyflavone-7-O-(2″,6″-O-E- dicoumaroyl)-β-glucopyranoside(4). Compounds 1-4 demonstrated good antioxidant activity. The average values of EC₅₀ were (19.5±1.8), (26.2±3.4), (22.9±2.7), (24.4±3.1)μg·mL^-1 for compounds 1-4 respectively. CONCLUSION Compounds 1-4 are isolated for the first time from the medicinal materials and can be used as natural antioxidants.