Optimization of natural deep eutectic solvent extraction process and activity study of total flavonoids from Dalbergia benthami prain

This study employed natural deep eutectic solvents (NADES) combined with ultrasound-assisted extraction to optimize the extraction process of total flavonoids from Dalbergia benthami Prain. Through single-factor experiments and response surface optimization, the optimal extraction conditions were determined as: Optimal NADES-11, composed of betaine and urea (molar ratio 1:2, 42 % moisture content), solid-liquid ratio 1:30 g/mL, extraction temperature 64°C, and an ultrasound duration of 41 min. Under these conditions, the total flavonoid yield reached 202.04 mg/g. Infrared spectroscopy analysis confirmed the successful preparation of NADES, and scanning electron microscopy observation revealed that NADES exhibited enhanced penetration and erosion capabilities, which facilitated the extraction of total flavonoids. Further studies found that the total flavonoids from Dalbergia benthami Prain had significant in vitro antioxidant activity, with the highest DPPH radical and ABTS radical scavenging rates reaching 92.02 % and 94.79 %, respectively. In addition, the total flavonoids in NADES-11 showed a highly significant synergistic antibacterial effect on Escherichia coli and Staphylococcus aureus. This study demonstrates that NADES-11 exhibits a higher extraction efficiency for the total flavonoids from Dalbergia benthami Prain than traditional organic solvents. It also boasts advantages like environmental friendliness. This research provides novel ideas and methods for the exploitation and utilization of Dalbergia benthami Prain, a precious and rare traditional Chinese medicine resource, and paves the way for its further comprehensive development and application.