Jeju seaweeds suppress lipopolysaccharide-stimulated proinflammatory response in RAW 264.7 murine macrophages

Objective:To investigate the anti-inflammatory effects of Jeju seaweeds on macrophage RAW264.7 cells under lipopolysaccharide（LPS）stimulation.Methods:Ethyl acetate fractions were prepared from five different types of Jeju seaweeds,Dictyopteris divaricata（D.divaricata）,Dictyopteris prolifera（D.prolifefa）,Prioutis cornea(P.comea,Grateloupia laceolata(G,lanceolate,and Cralcloupia filicina（G.filicina）They were screened for inhibitory effects on proinflammatory mediators and cytokines such as nitric oxide（NO）,prostaglandin E,,tumor necrosis factor-a（TNF-a）,and interleukin-6（11.-6）.Results:Our results revealed that D.divaricata,D.prolifera,P.cornea,G.lanceolata,and G.filicina potently inhibited I.PS-stimulaled NO production(IC;,values were 18.0,38.36,38.43,32.81 and 37.14μg/mL,respectively).Consistent with these findings,D.divtricata,D.prolifera,P.cornea,and G.fdicina also reduced the IPS-induced and prostaglandin E,production in a concentration-dependent manner.Expectedly,they suppressed the expression of inducible NO synthase and cyclooxygenase-2 at the protein level in a dose-dependent manner in the RAW264.7 cells,as detennined by western blotting.In addition,the levels of TNF-a and IL-6,released into the medium,were also reduced by D.divaricata,D.prolifera,P.cornea,G,lanceolata,and G.fdicina in a dose-dependent manner(IC;values for TNF-a were 16.11,28.21,84.27,45.52 and74.75μg/mL,respectively;IC;,values for IL-6 were 37.35,80.08,103.28,62.53 and 84.28μg/mL,respectively).The total phlorotannin content was measured by the Folin-Ciocalteu method and expressed as phloroglucinol equivalents.The content was 92.0μg/mg for D.divaricata,151.8μg/mg for D.prolifera,57.2μg/mg for P.cornea,53.0 pg/mg for G.lanceolata,and 40.2μg/mg for G.fdicina.Conclusions:Thus,these findings suggest that Jeju seaweed extracts have potential therapeutic applications for inflammatory responses.