Polysaccharide from Caulerpa lentillifera: extraction optimization with response surface methodology, structure and antioxidant activities

Ultrasonic-assisted extraction based on Response Surface Methodology was applied to isolate a polysaccharide (CLP) from Caulerpa lentillifera obtained in the South China Sea and the highest yield of the crude polysaccharide was 11.8%. CLP consisted of xylose, galactose, glucose and glucuronic acid in a molar ratio of 2.00: 1.00: 0.26: 0.04, with a molecular weight of 115 kDa. The content of uronic acids and sulfate groups in CLP was 14.10% and 27.40%, respectively. CLP presented good radical scavenging activities against O₂^·-, DPPH radical, while the scavenging activities against OH· and ABTS radical were not so satisfying.