Physico-chemical and DPPH-hydroxyl radical scavenging characteristics of crude polysaccharides from Sargassum thunbergii

This study aimed to determine the chemical composition and physical characteristics of the step gradient ethanol precipitates of celluclast-assisted hydrolysate from Sargassum thunbergii (STCFs). Crude polysaccharides were obtained via step gradient ethanol precipitation using celluclast-assisted hydrolysate from Sargassum thunbergii (STC). The yields of STCFs were STCF1 3.78 & PLUSMN; 0.01 %, STCF2 1.13 & PLUSMN; 0.06 %, and STCF3 0.17 & PLUSMN; 0.05 %. Polysaccharide and sulfate contents significantly increased in STCF1 and STCF2 but decreased in STCF3. Their physical characteristics were determined via Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), multi angle light scattering (MALS), and mass spectrometry (MS). FTIR showed that STCF1 and STCF2 have specific S--O, C-O-S bonds in sulfate, while STCF3 has a specific C--O bond in glucan. Purified STCF1 and STCF3 have similar MS patterns and structural characteristics (fucose containing galactan and glucooligosaccharide, respectively). MALS and SEM showed that STCF1 has a significantly larger average molecular weight and surface particles but those of STCF3 were significantly decreased. Overall, step gradient ethanol precipitation significantly altered several molecular characteristics and may contribute to S. thunbergii polysaccharide bioactivities.

Automated summary

This study aimed to determine the chemical composition and physical characteristics of the step gradient ethanol precipitates of celluclast-assisted hydrolysate from Sargassum thunbergii (STCFs). The yields of STCFs were STCF1 3.78 ± 0.01 %, STCF2 1.13 ± 0.06 %, and STCF3 0.17 ± 0.05 %. Polysaccharide and sulfate contents significantly increased in STCF1 and STCF2 but decreased in STCF3. Their physical characteristics were determined via FTIR, SEM, MALS, and MS. FTIR showed that STCF1 and STCF2 have specific S-O, C-O-S bonds in sulfate, while STCF3 has a specific C-O bond in glucan.