Sustainable Extraction of Hedera helix Bioactive Compounds via Synergy of Natural Deep Eutectic Solvent and...

Hedera helix (HE) contains diverse bioactive constituents, including triterpenoid saponins, flavonoids, and phenolic acids, which exhibit various pharmacological activities. In this study, ultrasound-assisted extraction (UAE) combined with natural deep eutectic solvent (NADES) was employed to enhance the extraction efficiency and elucidate the underlying mechanisms. Among the tested formulations, a ternary system composed of malonic acid (Mal), N,N'-dimethylurea (DMU), and 1,4-butanediol (1,4-BDO) achieved the highest efficiency for extracting eight target compounds from the HE leaves. In addition, the key interactions among NADES components were confirmed by Fourier-transform infrared (FT-IR) spectroscopy, providing valuable insights into the extraction mechanism. The UAE process was systematically optimized through single-factor experiments. Subsequently, response surface methodology (RSM) identified the optimal conditions as ultrasonic time of 45 min, solid/liquid ratio of 1:54 g/mL, and ultrasonic temperature of 42 °C. Scanning electron microscopy (SEM) elucidated the microstructural alterations in plant cell walls induced by NADES-UAE, alongside the enhanced penetration and disruption mechanisms. In vitro bioactivity revealed that the NADES-extracted HE exerted strong inhibitory effect on HT-29 colon cancer cells. Overall, these findings demonstrate the high effectiveness and sustainability of NADES-UAE for extracting HE bioactive compounds and provide valuable implications for the industrial-scale production of plant-based functional products.