Isolation,Purification And Structural Identification Of Polysaccharides From Sargassum Fusiforme And Against UVB-induced Skin Photoaging

Sargassum fusiforme,which belongs to the family of Sargassaceae,is a kind of brown algae extensively distributed in the coastal zones in Asia.It is used as traditional herbal medicine for thousands of years.Modern pharmacological studies demonstrated that Sargassum fusiforme contains various active ingredients.Polysaccharide is one of the most important active ingredients.In the present study,the isolation,purification,physicochemical property and structure-activity relationship of Sargassum fusiforme polysaccharides were investigated.In addition,protective effects of polysaccharides from Sargassum fusiforme against UVB-induced skin photoaging were also studied.Main results are listed as follows:1.The antioxidant activities of polysaccharides extracted by hot water with 6.59% polysaccharides yield were the strongest among those extracted by different methods.The basic chemical compositions of Sargassum fusiforme polysaccharides(SFP)including the content of carbohydrate,protein,sulfate and glucuronic acids were 58.10%,1.01%,9.85% and 17.66%,respectively;In addition,the monosaccharide composition analysis demonstrated that Sargassum fusiforme polysaccharides(SFP)consisted of L-fucose,rhamnose,galactose,glucose,fructose,xylose and mannose with molar percentages of 43.20%,3.50%,18.40%,1.50%,18.50%,5.90%,9.00%,respectively.2.Sargassum fusiforme polysaccharide(SFP)was extracted using hot water,then fractionated using a DEAE-Sepharose fast-flow column to obtain four fractions and the yield of SFP-P1 fraction(16.61%)were the highest among them.The basic chemical compositions of SFP-P1 fraction including the content of carbonhydrate,protein,sulfate and glucuronic acid were 87.24%,0.88%,9.85% and 17.66%,respectively;and the average molecular weight of SFP-P1 fraction was 113 kDa.In addition,the monosaccharide profile of SFP-P1 fraction was L-fucose,galactose,glucose,xylose and mannose with molar percentages of 13.17%,4.28%,1.95%,5.50%,75.10%,respectively.The percentage of(1?)or(1?6),(1?2)or(1?4),(1?3)glycosidic bond was 1.62%,60.69% and 37.69% according to the Smith degration analysis,respectively.The glycosidic linkages of SFP-P1 polysaccharide fraction were proven to be ?3,6)-?-D-Manp(1?,?4)-?-D-GalAp(1?,?4)-?-D-Xylp(1? and ?3,4)-?-D-GlcAp(1?.SFP-P1 fraction had no triple-helix conformation.3.The study of Sargassum fusiforme polysaccharides on UVB-Induced oxidative stress in hairless mice skin in vivo was carried out.The results indicated that oral supplementation with Sargassum fusiforme polysaccharides(SFP)could significantly enhance the activities of antioxidant enzymes,including superoxide dismutase(SOD)and catalase(CAT),and decrease the contents of reactive oxygen species(ROS)and malondialdehyde(MDA).In addition,SFP could significantly increase the content of water,relative weight of thymus and spleen in mice as well as suppress the levels of MMP-1,MMP-9 to reduce UVB-induced oxidative stress in hairless mice skin.These results suggested that Sargassum fusiforme polysaccharides can be used as a skin anti-photoaging agent.4.The study of Sargassum fusiforme polysaccharides fraction(SFP-P1)on UVBinduced oxidative stress in HaCaT cells in vitro was carried out.The results indicated that SFP-P1 could significantly enhance the activities of antioxidant enzymes,including superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px),and decrease the content of reactive oxygen species(ROS).In addition,SFP-P1 could significantly decreased the levels of MMP-1 and MMP-9.These findings suggest that Sargassum fusiforme polysaccharide can reduce UVB-induced oxidative stress in photo-aging HaCaT cells.