Structural properties and protective effect of Sargassum fusiforme polysaccharides against ultraviolet B radiation in hairless Kun Ming mice

Sargassum fusiforme polysaccharide (SFP) was extracted from Sargassum fusiforme by hot water boiling, concentration and ethanol precipitation. The composition was determined as 58.10 ± 2.12% carbohydrate, 1.01 ± 0.15% protein, 9.85 ± 0.96% sulfate group and 17.66 ± 0.54% glucuronic acid. The average molecular weight of SFP was 224 kDa. The monosaccharide composition of SFP was 43.2% L-fucose, 3.5% rhamnose, 18.4% galactose, 1.5% glucose, 18.5% fructose, 5.9% xylose and 9.0% mannose respectively. SFP showed significant protective effect against ultraviolet B (UVB) radiation in hairless Kun Ming (KM) mice by manipulating the skin water content and thymus and spleen indexes. SFP could also alleviate UVB-induced oxidative stress by enhancing the activities of superoxide dismutase (SOD) and catalase (CAT) and reducing the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) equivalents. The levels of matrix metalloproteinase (MMP)-1 and 9 were also suppressed in SFP treatments. These findings suggest that SFP could be used as a potential functional food supplement for skin protection.