A customizable CO2-Responsive supramolecular solvent for the simultaneous extraction of Multi-Polar phytochemicals from plants

A novel, sustainable, and customizable CO2-responsive supramolecular solvent (CO2-SUP) has been successfully developed to enable the simultaneous extraction of various polar phytochemicals from plant sources. An extraction system was formulated using N,N-dimethyloctylamine (DMOA) and water as the switching medium, with a 1:1 mass mixture of glycerol and 2-octanol added. The optimal CO2-SUP formulation comprised 30 % v/v DMOA, 40 % v/v C3:2-C8, and 30 % v/v H2O. Using Schisandra chinensis (Turcz.) Baill (S. chinensis) as a proof of concept, extractions were performed under optimized conditions, including a feed-to-liquid ratio of 100 mg/mL, a CO2 absorption duration of 25 min, and an ultrasound power of 175 W. Under these conditions, the extraction rates were 12.42 mg/g for lignans, 41 mg/g for polysaccharides (post-lyophilization), and 127 mg/g for S. chinensis oil. Notably, the lignan yield was 1.03 times higher than that achieved with methanol extraction. Additionally, the CO2-SUP system demonstrated the capacity to extract 82.1 % of the lignans from S. chinensis over four extraction cycles. The oil, lignan, and polysaccharide extracts exhibited significant antioxidant activity, capturing 81.2 %, 79.2 %, and 65.5 % of DPPH radicals, respectively. Additionally, density functional theory (DFT) calculations were conducted to elucidate the extraction mechanism of CO2-SUP, revealing that hydrogen bonding within CO2-SUP was a critical factor. Consequently, CO2-SUP shows promise as a green, recyclable solvent capable of simultaneously extracting a wide range of polar components, highlighting its significant potential for industrial applications.