Extraction, Purification, and Hydrolysis Behavior of Apigenin-7-O-Glucoside from Chrysanthemum Morifolium Tea

Apigenin-7-O-glucoside is an active phenolic compound in Asteraceae flowers and possesses remarkable therapeutic applications. However, its high price and low abundance in plants limit its use, meanwhile it would hydrolyze in the purification process. In this study, apigenin-7-O-glucoside extracted with ultrasound and purified with preparative HPLC from Chrysanthemum morifolium 'Huangju' was investigated, as well as its hydrolysis behavior and bioactivities. The optimized extraction conditions were: solid/liquid ratio: 1:20, extraction time: 35 min, temperature: 50 °C, and ultrasound power: 350 W. The content of apigenin-7-O-glucoside was up to 16.04 mg/g. Apigenin-7-O-glucoside was then purified with preparative HPLC from the extract, and confirmed by Q-TOF/MS. Apigenin-7-O-glucoside was partially hydrolyzed in acidic condition, and the hydrolysis rate depended on the pH value and temperature. The antioxidant activity increased as a result of the hydrolysis process. This study provided a green and effective way to obtain apigenin-7-O-glucoside and would be beneficial for further investigations into nutritional and functional aspects apigenin-7-O-glucoside and other glycosides.