Efficient fucoidan extraction and purification from Sargassum cristaefolium and preclinical dermal biological activity assessments of the purified fucoidans

• Fucoidans were isolated from S. cristaefolium by subcritical water extraction • Purify fucoidans with anion-exchange chromatography and centrifugal filter • Anti-oxidative properties of SWE samples were identified • Lower molecular weight SWE exhibited good anti-inflammation effects Fucoidan is a heterologous polysaccharide consisting mainly of L-fucose with sulfuric acid functional groups, and it is considered to be a repository of bioactive compounds with excellent therapeutic and medical potential, such as antioxidant, anti-inflammatory, antiangiogenic, antitumor, and antibacterial capabilities. Subcritical water extraction was used to extract fucoidan from Sargassum . Fucoidans with different molecular weight (LMW) fractions were obtained by H 2 O 2 hydrolysis, and the effect of LMW on their bio-functions was investigated. Metal chelating, iron-reducing and free radical scavenging properties of purified fucoidans demonstrated outstanding anti-oxidative capacities of SWE fractions. In cellular viability assay, SWE was not inhibitory towards RAW 264.7, HaCaT, and Hs68 cells, even when high dosages were used. Anti-inflammatory activity was brought about by SWE administration after UVB exposure, demonstrating that the injured skin tissue was repaired and collagen was regenerated, as shown by in vitro and in vivo tests.