Extraction and activity study of astragalus saponins by ultrasound combined with cold isostatic pressure technique

In this study, the cold isostatic pressure method was combined with ultrasonic extraction, and the method of ultrasonic extraction followed by cold isostatic pressure (ULT-CIP) extraction was established to extract astragalus saponins. The different extraction conditions were optimised using single factor experiments, Box-benhken design (BBD). The maximum extraction rate of 56.2486 ± 0.0055 mg/g was achieved by the ULT-CIP treatment method at 400 MPa, 4 min with ultrasonic power of 370 W and ultrasonic time of 60 min. Structural analysis of the characterisation indicated that ULT-CIP treatment resulted in structural fragmentation of plant cells, provided a basis for increasing the extraction content. Then, LC-MS was used to detect and analyze several different extracts of astragalus saponins, the maximum extraction yield was 56.2486 ± 0.0055 mg/g. Finally, in vitro antioxidant activity, anti-inflammatory activity and antibacterial activity were carried out, which proved that the astragalus saponins extraction after ULT-CIP treatment still had better activity. This is specifically reflected in the fact that after ULT-CIP treatment, the antioxidant activity of ASE reached a maximum of 84.31%, and the inhibition rate against inflammatory factors increased by a maximum of 46.15%. Therefore, ULT-CIP is an effective method for extracting active ingredients from plants that can increase the extraction rate of active ingredients.