Study On The Chemical Compositions From Ethyl Acetate Extract Of Sargassum Fusiforme

Sargassum fusiforme has been applied as a source of food and traditional medicine in China.Due to its special pharmacological activities,including hypoglycemic,antitumor,immunological activity and anti inflammatory activity,researchers paid more attention to its bioactivity constituents.While the bioactivity research almost focused on the polysaccharides of Sargassum fusiforme.There were a very limited number of publications about biological activity mechanism of chemical compositions.Present research focused on chemical compositions separation and biological analysis of ethyl acetate extract from Sargassum fusiforme.The research includes two parts:1.High-speed counter-current chromatography(HSCCC)was applied for the separation of bioactive compound of ethyl acetate extract from Sargassum fusiforme and biological activity evaluation.2.Combined with microbial fermentation technology,separate the changes compositions by fermentation and evaluate its activity.First,separate bioactive compound of ethyl acetate extract from Sargassum fusiforme by HSCCC and evaluate its activity.In research,the ?-glucosidase assay results showed that the ethyl acetate extract with IC50 of 60.59�0.42 ?g/mL.Under the n-hexane-methanol-water ratios(5:4:1,v/v)solvent system,19.7 mg dibutyl phthalate(DBP)with the purity of 95.3%was isolated from 200 mg of the ethyl acetate extract.The IC50 against a-glucosidase was 239.59�0.72?M(66.61 �0.20 ?g/mL).Its IC50 of the inhibitory activity against PTP1B assayed in vitro was 14.05�0.06 ?M(3.91 �0.02 ?g/mL),which was further explained by molecular docking.The result of molecular docking showed that the interaction with Gln266 though hydrogen bonding was considered as the main force to stabilize DBP within the binding pocket region of PTP1B.In addition,establishment of hydrophobic pocket with the nonpolar amino acids(Ala217,Ile219,and Gly220)of PTP1B were responsible for governing inhibitor potency of the compound.Second,screening the Sargassum fusiforme fermentation strains and optimizes the fermentation conditions.Separation the active ingredients of ethyl acetate extract from Sargassum fusiforme fermentation products and validation its biological activity.Screening the Sargassum fusiforme fermentation strains was Aspergillus oryzae FFCC39 under the bioassay-guidance of a-glucosidase inhibitory activity.To determine the optimal fermentation condition,central composite experimental design was applied,IC50 of a-glucosidase inhibitory activity as response value for the response surface and contour plot.The analysis results showed that the optimal conditions of fermentation was inoculation quantity 10%,pH 4.7 and C/N=4.8.Under the n-hexane-ethyl acetate-methanol-water ratios(1:5:1:5,v/v)solvent system,9.2 mg target compound with the purity of 94.6%was isolated from 200 mg of the ethyl acetate extract.The compound showed a-glucosidase inhibitory activity with IC50 value of 48.06�0.04 ?g/mL.The IC50 value against PTP1B was 10.54�0.07 ?g/mL which indicated the potent hypoglycemic activity.