Ultrasonic extraction of cardiac glycosides from <i>Adonis amurensis</i> Regel et Radde roots: process optimization and content determination

This study optimised the ultrasonic-assisted extraction of cardiac glycosides from <i>Adonis amurensis</i> Regel et Radde roots, increasing the extraction yield by 51.30% to 87.42 mg/g. The optimal conditions were ethanol 30%, liquid-to-solid ratio 25:1 (mL/g), ultrasonic time 58 min, temperature 67 °C, and power 250 W. For the first time, high-performance liquid conditions were established to separate four cardiac glycosides. After optimisation, the contents of apocynin and convallatoxin increased 3-4 times compared with the hot water bath method. Scanning Electron Microscope imaging confirmed that ultrasound caused more severe cell wall damage, enhancing extraction efficiency. In summary, this study provides a basis for the extraction methods of cardiac glycosides and the efficient utilisation of cardiac glycosides, the core medicinal components in the roots of <i>Adonis amurensis</i> Regel et Radde.