Isolation,Identification And Biological Functions Of Fucoxanthin Stereoisomers From Saccharina Japonica

In recent years,our country attaches more and more attention to the exploitation and utilization of marine resources,and it is extremely urgent to improve the processing capacity of marine resources.In traditional kelp industry,kelp pigment and other fat-soluble substances are mostly abandoned as waste liquid.Fucoxanthin,as the main component of carotenoids in Saccharina japonica,has great biological activity.At present,it has been widely concerned by food,cosmetics,drugs and other industries,because it has good business prospects and commercial value.In this experiment,Saccharina japonica was used as raw material to extract pigments from it with ethanol,and the feasibility of enriching fucoxanthin with macroporous resin was verified.Results show that X-5 macroporous resin to fucoxanthin as strong adsorption,was investigated using ethanol and water as eluent to fucoxanthin elution effect,the results show that more than 60%ethanol aqueous solution can effectively elute fucoxanthin.The pigments from Saccharina japonica were extracted with ethyanol and the fucoxanthin stereisomers were purified by column chromatography.Finally,three fucoxanthin stereisomers were prepared by preparative high performance liquid chromatography?HPLC?.The structures of the fucoxanthin stereisomers were characterized by ultraviolet-visible spectroscopy?UV-VIS?,mass spectrometry?MS?and nuclear magnetic resonance?NMR?.The in vitro antitumor activity of the fucoxanthin stereisomers was studied using MDA-MB-231 breast cancer cell line.The results showed that fucoxanthin isomers possessed great inhibitory effects against the growth of breast cancer cells.The 13-cis and 13'-cis fucoxanthin mixtures showed the highest inhibitory activity,and the IC₅₀ value was 23.71?g/mL.In addition,the IC₅₀values of the all trans-fucoxanthin and the 9'-cis-fucoxanthin were 45.30?g/mL and27.09?g/mL,respectively.Further,the qPCR experiment suggested that the fucoxanthin stereisomers may inhibit the growth of breast cancer cells by down-regulating the expression of NF-?B related genes.The free radical scavenging activity of fucoxanthin isomers was investigated.All-trans fucoxanthin had higher DPPH radical scavenging activity,13-cis and 13'-cis fucoxanthin showed stronger scavenging ability to hydroxyl radicals,and all-trans fucoxanthin and 13'-cis fucoxanthin had higher scavenging ability to superoxide radicals than 9'-cis fucoxanthin.