Abstract:
Polysaccharides of marine algae exhibit different structural characteristics and interesting biological functions. In this
study, crude polysaccharides (CP) of eleven Sri Lankan marine algae obtained through hot water extraction and ethanol
precipitation were investigated for DPPH, alkyl, and hydroxyl radical scavenging activities using electron spin resonance
spectrometry and for intracellular reactive oxygen species scavenging activity in the Chang liver cell line. Characteriza-
tion of CPs was done by Fourier transform infrared (FTIR) spectroscopy and by analysis of the monosaccharide compo-
sition. Time-dependent density functional theory quantum-chemical calculations at the RB3LYP/6-31G(d,p) level for
constructed dimeric units of the corresponding polysaccharides were used to resolve the FTIR spectra. CPs from Chnoos-
pora minima showed the highest DPPH and alkyl radical scavenging activities and higher intracellular reactive oxygen
species scavenging effects for both AAPH and H2O2 induced ROS production in “Chang” cells. The major polysaccharide
constituent in C. minima CP was identified as fucoidan and it displayed a higher sulfate content. The degree of sulfation
of these polysaccharides suggests a positive correlation with the observed antioxidant properties.
