Green and Efficient Extraction of Soybean (Glycine max (L.) Merr.) Isoflavones Using Natural Deep Eutectic Solvents-Based Ultrasound-Assisted Extraction

Abstract Soybean ( Glycine max (L.) Merr.) is considered a key global food source, valued for their bioactive isoflavones, which exhibit antioxidant, anti-inflammatory, and phytoestrogenic properties. However, conventional solvent-based extractions face challenges such as low selectivity, inefficient recovery of glycosylated isoflavones, and environmental concerns. This study developed a green, efficient extraction method using Natural Deep Eutectic Solvent (NADES)-based ultrasound-assisted extraction (UAE). A choline chloride-ascorbic acid (1:1) NADES system yielded 795.8 µg/g DW isoflavones, outperforming conventional 50% ethanol extraction (723.5 µg/g DW). Optimization using Box-Behnken Design identified 39% water content, 55 °C, and 64 min as ideal conditions, with water content and temperature being key factors. These optimized NADES conditions resulted in isoflavone extraction yield of (1076.78 µg/g DW). COSMO-RS computational modeling revealed NADES-isoflavone interactions, emphasizing hydrogen bonding and polarity. This eco-friendly method enhances efficiency, reduces environmental impact, and supports NADES as a sustainable alternative for bioactive phytochemical extraction.