Purification of chicoric acid from dandelion herbal pieces using macroporous resin combined with HSCCC and its antioxidant capacity in human keratinocytes

Dandelion (Taraxacum mongolicum Hand. - Mazz.) is a traditional Chinese medicinal herb rich in active ingredients such as flavonoids and polyphenols, which are used to treat swelling and inflammation-related diseases. In the present study, total flavonoids and polyphenols in dandelion herbal pieces (Taraxaci Herba) extracts were purified by HPD-500 resin column chromatography, and the total flavonoid purity in purified extracts E80% was 5.3 times that of before purification, reaching 43.98 %. The purified extracts E80% were analyzed by UHPLC–QTOF–MS and 8 phenolic acid compounds were identified, including caffeic acid, chlorogenic acid, and chicoric acid. Moreover, high-speed countercurrent chromatography method was established to separate chicoric acid from E80%. n-hexane-ethyl acetate-methanol-0.5 % acetic acid in water (2:7:2:7, v/v/v/v) was selected as the solvent system. Chicoric acid with a purity of 95.44 % was obtained with the flow rate of 2.0 mL/min, the speed of 850 r/min, the system temperature of 35 °C and sample loading of 100 mg. In vitro bioassay showed that chicoric acid presented impressive antioxidant activities in SDS-induced human keratinocytes by promoting cell proliferation, increasing superoxide dismutase (SOD) activity, reducing the reactive oxygen species (ROS) level, stabilizing the mitochondrial membrane potential, and inhibiting cell apoptosis. Collectively, these results lay a theoretical basis for the industrial separation of natural antioxidant compounds.