Chemical Characterization and Immunomodulatory Activity of Fucoidan from Sargassum hemiphyllum

Abstract

Fucoidan is a sulfated algal polyanionic polysaccharide that possesses many biological activities. In this paper, a fucoidan (SHF) polysaccharide was extracted from <i>Sargassum hemiphyllum</i> collected in the South China Sea. The SHF, with a molecular weight of 1166.48 kDa (44.06%, <i>w</i>/<i>w</i>), consisted of glucose (32.68%, <i>w</i>/<i>w</i>), galactose (24.81%, <i>w</i>/<i>w</i>), fucose (20.75%, <i>w</i>/<i>w</i>), xylose (6.98%, <i>w</i>/<i>w</i>), mannose (2.76%, <i>w</i>/<i>w</i>), other neutral monosaccharides, and three uronic acids, including glucuronic acid (5.39%, <i>w</i>/<i>w</i>), mannuronic acid (1.76%, <i>w</i>/<i>w</i>), and guronuronic acid (1.76%, <i>w</i>/<i>w</i>). The SHF exhibited excellent immunostimulatory activity. An immunostimulating assay showed that SHF could significantly increase NO secretion in macrophage RAW 264.7 cells via upregulation of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) levels based on both gene expression and protein abundance. These results suggest that SHF isolated from <i>Sargassum hemiphyllum</i> has great potential to act as a health-boosting ingredient in the pharmaceutical and functional-food fields.