Sulfated polysaccharide from Sargassum tenerrimum attenuates oxidative stress induced reactive oxygen species production in in vitro and in zebrafish model

•Sulfated polysaccharide (SP) was successfully isolated from Sargassum tenerrimum.•The structural features of SP were characterized by FT-IR, GC–MS, 1H NMR.•The molecular weight of SP was found to be 31 kDa.•SP possess in vitro anti-oxidant effects in fibroblast cells.•SP exhibits a protective effect against H2O2 induced oxidative stress in zebrafish. The sulfated polysaccharide (SP) was isolated from the brown alga S. tenerrimum. The chemical composition of SP composed of 57 ± 0.29% of total sugar, 1.14 ± 0.28% of protein and 25.6 ± 0.45% of sulfate. Elemental analysis of SP shows 28.8% of carbon, 4.02% of hydrogen and 0.29% of nitrogen. The molecular weight of SP was estimated as 31 kDa. Further, the SP was characterized through FT-IR, 1H-NMR, GC–MS, XRD and TGA analysis. The DPPH and ABTS radical scavenging activity of SP showed 34.03–62.70% and 22.94–38.04% at the concentration of 25–125 μg/mL respectively. In addition, SP exerted a protective role against H2O2 mediated oxidative stress in fibroblast cells through scavenging intracellular ROS. Furthermore, ROS generation and cell death were significantly decreased in SP treated zebrafish embryos at 150 μg/mL, whereas the survival rate was increased. The protective effect of SP against oxidative stress might be utilized in pharmacological industries.