Development of a hydrophobic deep eutectic solvent-based nanoemulsion for enhanced extraction coupled with delivery of lignans from Schisandra chinensis

The growing demand for sustainable technologies has inspired interest in green extraction and delivery systems for plant-derived natural products. This study developed a hydrophobic deep eutectic solvent (HDES)-based nanoemulsion for efficient extraction and delivery of lignans from Schisandra chinensis . Through systematic screening, a HDES composed of menthol and octanoic acid (Men:C 8 ) was selected for extraction and subsequent preparation. After optimizing extraction parameters (solid-liquid ratio 40 mg/mL, extraction temperature 60°C, extraction time 40 min), the HDES demonstrated superior extraction efficiency (6.497 ± 0.008 mg/mL), representing a 1.12–2.08 fold improvement compared to water or conventional organic solvents. The extract-containing HDES was formulated into a nanoemulsion (HDES-NE) that exhibited excellent stability under various environmental conditions (pH, temperature, centrifugal force, storage time). The preparation conditions were optimized to establish optimal process parameters (oil-water ratio 2:17, homogenization time 3 min, ultrasonic power 360 W). The resulting nanoemulsion exhibited nanoscale characteristics (average particle size 115.78 nm, PDI < 0.3, and a zeta potential of −18.11 mV), with spherical morphology directly visualized by TEM, and no phase separation or precipitation. HDES-NE showed significant tyrosinase inhibition (IC 50 0.26 ± 0.04 mg/mL; 97.73% inhibition at 4 mg/mL), substantial UVB protection (SPF = 17.58 ± 0.27), and antimicrobial activity against skin pathogens, including Staphylococcus aureus and Cutibacterium acnes . This integrated approach, combining green extraction with nano-delivery, offers an environmentally friendly alternative for developing natural bioactive products.