Microwave-assisted extraction, partial purification and biological activity in vitro of polysaccharides from bladder-wrack (Fucus vesiculosus) by using deep eutectic solvents

Based on natural deep eutectic solvents (DESs), microwave-assisted green extraction was applied for production of polysaccharides from bladder-wrack (Fucus vesiculosus). In this study, nine different combinations of deep eutectic solvents were evaluated for extraction of polysaccharides from bladder-wrack, and the results showed that DES system composed of choline chloride and 1,4-butanediol with molar ratio of 1:5 possessed the optimal extraction efficiency for polysaccharides. A three-level and four-variable Box-Behnken design (BBD), a specific design of response surface methodology (RSM), was used to determine the optimum extraction conditions for the maximum yields of polysaccharides from bladder-wrack by using DESs. The maximum yields of polysaccharides attained 116.33 mg/g within DES water content of 32%, extraction time of 35 min, extraction temperature of 168 °C and solid–liquid ratio of 39 mg/mL. After partial separation and purification of the polysaccharides extracted by DESs, antioxidant activity and anticancer activity in vitro were evaluated. The results revealed that polysaccharides extracted from bladder-wrack exhibited excellent antioxidant activities in vitro including DPPH and ABTS radical-scavenging activity. For human cervical cancer HeLa cells, the polysaccharides possessed a strong inhibition effect on the growth rate. So these results indicate that deep eutectic solvent, as an environmentally-friendly solvent, can be applied to extract polysaccharides from multifarious plant materials.