Towards optimizing the conventional and ultrasonic-assisted extraction of sulfated polysaccharides from marine algae

Recently, there has been a growing interest in sulfated polysaccharides extracted from various natural sources due to their versatile biological activities that find great use in biomedical and industrial applications. In the present study, sulfated polysaccharides were extracted from green algae, Ulva lactuca and red algae, Jania rubens collected from Alexandria city coast, Egypt. Conventional and ultrasonic-assisted extraction methods were investigated under different operating parameters and the optimum conditions for extraction were obtained based on the yield. Algal extracts with optimum SPs yields were then tested for their phenolic and sugar contents, as well as their 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) antioxidant activities. Optimum yields of both green and red algae were obtained via extraction under ultrasonic conditions for 4h. Higher yields were produced from the green algae as compared to the red ones. However, red algal extracts showed relatively higher antioxidant activities, possibly due to their higher mannose content.