Chemical characterization and antioxidant activity of sulfated polysaccharides from Navicula sp

Sulfated polysaccharides were extracted from Navicula sp. cultivated at three wavelengths: white (WSPN), red (RSPN) and blue (BSPN) with yield rates of 3.4, 3.9 and 4.4 (% w / w dry biomass basis) respectively. Analysis of these polysaccharides using gas chromatography showed that they contain glucose, galactose, rhamnose, xylose and mannose as main neutral sugars. The amount of rhamnose was higher in WSPN. The molecular weight ( Mw ) value was 17, 107 and 108 kDa for WSPN, BSPN and RSPN, respectively. The sulfate content in WSPN was higher (0.40% w/w ) than in the BSPN and RSPN. The polysaccharides recovered from Navicula sp. presented antioxidant activity, which could be related to the molecular structural characteristics such as Mw and sulfate content. The scavenging activity was higher in WSPN (DPPH 49% and ABTS + 68 μmol Trolox/g), than in the BSPN and RSPN samples. The WSPN possess a high antioxidant capability, thus this sulfated polysaccharide might be a potential antioxidant for biotechnological applications.