An Optimized Method for Extraction and Characterization of Phenolic Compounds in Dendranthema indicum var. aromaticum Flower.

Dendranthema indicum var. aromaticum plant has been widely used as herbal medicine in China, however, the material basis responsible for the therapeutic benefits remains largely unclear. This study aimed to provide an optimized method for extracting and characterizing phenolic compounds in D. indicum var. aromaticum flower. Firstly, an ultrasound-assisted method combined with central composite circumscribed (CCC) design was applied to optimize phenolic compound extraction. Ethanol-acetic acid (70%:2%, v/v) was selected as solvent, and the optimal extraction condition was: extraction temperature, 57 °C; solid/liquid ratio, 1:30 g/mL; extraction time, 20 min. Secondly, an effective and economic HPLC-PDA-ESI-MSⁿ method was established and validated for phenolic compound characterization and quantification. As a result, 14 phenolic compounds were identified, including 8 phenolic acids and 6 flavonoids, and for the first time, oleuropein derivatives, chrysoeriol, and tricin are reported in D. indicum var. aromaticum flower. The content of phenolics identified by HPLC-MSⁿ was 6.42 ± 0.32 mg/g DW. The optimized method for extraction and characterization of phenolic compounds has significant meaning to future pharmaceutical and medicinal research on D. indicum var. aromaticum, and the results in this study can provide references for herbal research.