Chemical characterisation of sulfated polysaccharides from the red seaweed Centroceras clavulatum and their in vitro immunostimulatory and antioxidant properties

Phycocolloids have aroused research interest due to their remarkable functional properties, including immunostimulatory and antioxidant activities. In this study, the yield of Centroceras clavulatum sulfated polysaccharides (CCSP) was 4.36% and had a sulfate content of 9.42%. The main monosaccharide units of CCSP were galactose (25.23 ± 0.81 mg/l) and glucose (4.32 ± 0.31 mg/l). Specifically, FT-IR spectrum of CCSP revealed a peak at 843 cm⁻¹ which indicates the occurrence of sulfate groups on C-4 of galactose. CCSP stimulated Carp Leukocyte Culture (CLC) cell line to generate reactive oxygen species (ROS) and nitric oxide (NO) in a dose-dependent manner. Remarkably, exposure of CLC cells to CCSP at a dose of 12.5 µg/ml significantly increased superoxide dismutase activity and reduced malondialdehyde level. These results suggest that CCSP could stimulate CLC cells without compromising the intracellular antioxidant system, hence, may have potential applications as nutraceuticals.