Ultrasonic-assisted extraction of flavonoids from Abelmoschus manihot flowers: RSM-ANN optimization, characteristics analysis, antioxidant activities, and molecular simulation

Ultrasonic-assisted extraction (UAE) was employed to extract flavonoids from Abelmoschus manihot ( A. manihot ) flowers. The extraction process was optimized using Response Surface Methodology (RSM) and Artificial Neural Network (ANN) model. Both models yielded good outcomes, and ANN model excelled in prediction accuracy over RSM. The optimal extraction conditions were an ultrasound time of 36.8 min, an ultrasound power of 228 W, a liquid/solid ratio of 54.9 mL g⁻¹ , and an ethanol content of 59.8 %, resulting in a total flavonoid content of 51.53 ± 0.66 mg g⁻¹ . UPLC-MS analysis confirmed hyperoside, quercetin 3-glucoside, rutin, quercetin, and myricetin as the major compounds in the optimized extracts. Scanning electron microscopy (SEM) demonstrated that UAE can significantly enhance extraction efficiency. FTIR revealed minor structural differences between UAE and conventional extraction (CE) extracts. DPPH and ABTS assays showed that antioxidant activity of the UAE-optimized extract was significantly higher than that of CE. Molecular dynamics simulation revealed that the extraction mechanism of flavonoids is related to ethanol concentration, providing molecular insights for optimizing the extraction scheme. Collectively, this research demonstrated the efficiency of UAE in extracting flavonoids from A. manihot flowers, providing a foundation for its application in the pharmaceutical and functional food industries. • RSM and ANN model were used to optimize the ultrasonic-assisted extraction conditions of flavonoids from A . manihot flowers. • UPLC-MS quantified 19 flavonoid components with representativeness and antioxidant activity in Abelmoschus manihot flowers. • The flavonoid extract from A . manihot flowers obtained by ultrasonic-assisted extraction had higher antioxidant activity. • Experiments coupled with MD simulations elucidated flavonoid extraction mechanisms with varying ethanol concentrations. • It provides theoretical and experimental support for developing the functional food and medical value of A. manihot flowers.