Isolation, purification, partial characterisation and evaluation of the in vitro antioxidant and anti-inflammatory potential of fucoidan from Sargassum fluitans from Lagos Badagry coast

Abstract Sargassum fluitans is a species of free-floating brown macroalgae (seaweed) found in the Atlantic Ocean and Caribbean Sea, often forming massive mats that wash onto beaches. Its presence hinders fishing activities by locals and recreational activities around the beaches. Sargassum contains steroids, polyphenols and polysaccharides like alginate and fucoidan amongst many others. Fucoidan is a negatively charged and sulphated polysaccharide with known pharmacological activity. Thus, this study was intended to isolate, partially characterise and evaluate the in vitro antioxidant and anti-inflammatory activities of purified fucoidan from Sargassum fluitans from Badagry coast. The seaweed was collected and fucoidan was isolated using acid-extraction method for optimal yield. Purification was done using ion exchange chromatography, and partial characterisation was conducted with HPLC, FTIR and NMR. In vitro antioxidant (DPPH and H 2 O 2 scavenging ability, reducing power, ferric reducing antioxidant power), and anti-inflammatory (NO, Protein inhibition and albumin denaturation assays) of the purified fucoidan were monitored and compared with standards (Ascorbic acid and Aspirin, respectively). The purified fucoidan had a higher fucose (67.96%) and sulfate (28.41%) content compared to the crude fucoidan. Compared to fucoidan from some tropical and subtropical species like S. siliquosum , and S. hemiphyllum , our isolate had higher sulfate but similar fucose content. In vitro antioxidant and anti-inflammation activities of the purified fucoidan was significantly higher (p < 0.05) compared to the standard ascorbic acid and aspirin, respectively. These findings suggest potential application of this readily available bioresource currently regarded as an environmental nuisance.