Evaluation of the antioxidant activity of enzymatically-hydrolyzed sulfated polysaccharides extracted from red algae; Pterocladia capillacea

•Low and high-molecular weight sulfated polysaccharides were extracted from red algae.•High molecular-weight sulfated polysaccharide fractions were enzymatically hydrolyzed.•Viscozyme hydrolysate showed superior DPPH scavenging activity of 92%.•High phenolic content and antibacterial activity were also exhibited by Viscozyme hydrolysate.•Antioxidant activity could be related to chain length, as well as phenolic and sugar contents.

Sulfated polysaccharides (SPs) were extracted from red algae, Pterocladia capillacea and the produced fractions were hydrolyzed using different enzymes. 1,1-Diphenyl-2-Picryl-Hydrazyl (DPPH) and peroxide scavenging activities as well as phenolic content of the extracted fractions and their hydrolysates were determined. Viscozyme hydrolysate exhibited the highest phenolic content and a DPPH scavenging activity of about 92% with more than 50% increase over its mother fraction. It also showed a high antibacterial activity relative to commercial antibiotics. Phenolic content determination and HPLC analysis suggested that the high antioxidant activity of viscozyme hydrolysate could be owed to its short-length chain and its high content of phenolic compounds as well as the predominance of mannose and galactose sugars in the polysaccharide chain.