Polysaccharides from Enteromorpha tubulosa: Optimization of extraction and cytotoxicity

An ultrasound-assisted procedure for the extraction of water-soluble polysaccharides from Enteromorpha tubulosa was studied by using response surface methodology. Three independent variables including extraction time, extraction temperature, and ratio of liquid to raw material were investigated by single-factor experiments. A three-factor-three-level Box–Behnken design was adopted to optimize the extraction process parameters. A highly significant second-order polynomial equation was fitted by using multiple regression analysis. The optimal extraction conditions were obtained as follows: extraction time 36 min; extraction temperature 69 °C; and ratio of liquid to raw material 45 mL/g. By experiments with these conditions, the extraction yield was 16.04%, which was well matched with the predicted value. The obtained polysaccharides were evaluated for cytotoxicity in vitro against human breast cancer cell line MCF-7 and the results showed that the polysaccharides possessed potent cytotoxicity. Practical applications Seaweeds are one of the largest numbers and species of marine plants, and their bioactive compounds, especially algal polysaccharides, have become the focus of research in the field of food and medicine. Moreover, many algal polysaccharides have been gradually applied to food and medicine owing to their varied biological activities, such as antivirus, antitumor, antiradiation, antimutation, antioxidation, and enhancing immunity. However, there is no universal extraction process for polysaccharides from the different seaweeds because of the different structures of the seaweeds and the varying compositions of algal polysaccharides. In the current research, an ultrasound-assisted procedure for the extraction of water-soluble polysaccharides from Enteromorpha tubulosa was studied by using response surface methodology, and the optimal extraction conditions were obtained so as to provide references for the mass productions in the factories.