Optimisation, Component Analysis, and Bioactivity Evaluation of Sunflower Calathide Flavonoids Obtained Using Ultra-High-Pressure Extraction

This study aims to achieve the efficient preparation of sunflower calathide flavonoids (SCF) through optimized processes and to elucidate their composition and bioactivity. Total flavonoids were prepared by optimizing the ultra-high-pressure extraction (UHPE) process using a combination of single-factor experiments and response surface methodology, followed by purification and enrichment via macroporous resin. The components were identified with UPLC-QTOF-MS/MS technology, and their antioxidant activity and inhibitory capacity against xanthine oxidase (XOD) were systematically evaluated. The optimal extraction conditions were determined as follows: an extraction pressure of 290 MPa, a holding time of 8 min, an ethanol concentration of 67%, and a solid-to-liquid ratio of 1:14 g/mL. Under these conditions, the total flavonoid extraction yield reached 13.52 mg/g, which was further enriched to 16.74 mg/g after purification by macroporous resin. A total of 32 flavonoid compounds were identified, and the purified extract exhibited stronger free radical scavenging ability, total reducing power, ferric ion reducing activity, and XOD inhibitory effect compared to the unpurified extract. The combination of UHPE with macroporous resin separation technology effectively enriches SCF, and the resulting extract possesses both antioxidant and xanthine oxidase inhibitory activities, providing a theoretical basis and technical support for its industrial production and application.