Ultrasonic-assisted extraction of flavonoids from Amomum villosum Lour. Using natural deep eutectic solvent: Process optimization, comparison, identification, and bioactivity

Amomum villosum Lour. (A. villosum) is widely utilized in culinary and medicinal contexts due to its rich diversity of bioactive compounds. In this study, an ultrasonic-assisted extraction (UAE) method using a natural deep eutectic solvent (NaDES) was employed to extract flavonoids from A. villosum. The NaDES composed of betaine and glycerol (Bet-Gly) exhibited effective performance as an extraction solvent, as evidenced by its high efficiency. Optimal extraction conditions (water content: 30 %, solid-liquid ratio: 1:20 g/mL, temperature: 70 °C, ultrasonic power: 85 % P, time: 30 mins) were established via single-factor experiments. The maximum total flavonoid content (TFC) of 82.22 ± 0.39 mg rutin equivalent per gram dry weight (mg Rut/g DW) was achieved under optimized conditions. Comparative studies revealed that the UAE-NaDES method afforded higher TFC and DPPH radical scavenging activity values, broader flavonoid diversity, and demonstrated a better capacity to stabilize them compared to conventional solutions. Furthermore, NaDES exhibited favorable biocompatibility properties, and the resulting extract displayed remarkable anti-inflammatory and anti-cancer effects. These findings demonstrate that NaDES is an efficient solvent for flavonoids extraction from A. villosum, with potential applications in food and pharmaceutical industries, thereby minimizing solvent removal steps.