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

This study optimised the ultrasonic-assisted extraction of cardiac glycosides from Adonis amurensis 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 Adonis amurensis Regel et Radde. After optimisation, the total cardiac glycoside extraction content increased by 51.30%. After optimisation, the contents of apocymarin and convallatoxin in the extract increased by 3–4 times. Ultrasound increases extraction efficiency by breaking cell walls.