Isolation and purification of flavonoids from <i>Euonymus alatus</i> by high‐speed countercurrent chromatography and neuroprotective effect of rhamnazin‐3‐O‐rutinoside in vitro
Wenjuan Wang, Yuanyuan Liu, Fenfang Che, Hao Li, Jiangang Liu, Nan Wu, Yanxiang Gu, Yun Wei
Abstract
Abstract The flavonoids from Euonymus alatus exhibit many biological activities including significant antioxidant, anti‐inflammatory, anti‐cancer. In this work, a high‐speed countercurrent chromatography method for the isolation and purification of flavonoids from crude extracts of Euonymus alatus was established. The effects of several solvent systems on the separation efficiency of target compounds in the extract of Euonymus alatus were studied. The solvent system composed of n ‐hexane‐ethyl acetate‐methanol‐water at a volume ratio of (3:5:3:5, v/v) was chosen, in which the lower phase was used as the mobile phase at the rotation speed of 800 rpm and flow rate of 2.0 mL/min. The three flavonoids were obtained and identified as patuletin‐3‐O‐rutinoside, rhamnazin‐3‐O‐rutinoside, and dehydrodicatechin A by mass spectroscopy and nuclear magnetic resonance, and the quantities of patuletin‐3‐O‐rutinoside, rhamnazin‐3‐O‐rutinoside, and dehydrodicatechin A were 2.2, 9.7, and 1.8 mg, respectively. The results indicated that high‐speed countercurrent chromatography was a simple and efficient method for the isolation and purification of flavonoids from the crude extracts of Euonymus alatus . The cellular antioxidant activity experimental result indicated that rhamnazin‐3‐O‐rutinoside could alleviate H 2 O 2 ‐induced oxidative stress.