Enzyme-assisted ultrasonic extraction, optimization, purification, and biological activity analysis of flavonoids from Rosa sterilis fruits

Rosa sterilis is an underexplored source of bioactive compounds, particularly known for its rich flavonoid content and biological activities. This study systematically investigated the extraction, purification, and biological activity of flavonoids from R. sterilis fruits. Through optimized enzyme-assisted ultrasonic extraction (50 % ethanol, 50 mL/g liquid-solid ratio, 70 min, 3 % enzyme dosage), total flavonoids were extracted at 129 mg rutin equivalents/g dry R. sterilis fruit powder. This yield was further enhanced to 147 mg/g via response surface optimization. AB-8 macroporous resin was identified as the most effective for total flavonoids purification, with adsorption following pseudo-second-order kinetics and Langmuir isotherm models. Thermodynamic analysis indicated spontaneous, exothermic, and primarily physical adsorption. After purification, flavonoid purity increased from 35.2 % to 82.3 %. The enriched extract demonstrated strong antioxidant activities, scavenging DPPH^•, ABTS^•+, and hydroxyl radicals, and showed significant inhibition of α-glucosidase, α-amylase, and pancreatic lipase in a dose-dependent manner. UHPLC-MS/MS identified 32 flavonoids, including ugonin B, epicatechin and apigenin derivatives. These results suggest R. sterilis total flavonoids have high antioxidant and enzyme inhibitory potential, supporting their development as functional food ingredients or nutraceuticals.