- 298 - Immunomodulatory Effects of Supplementation with Extracts from the Marine Brown Alga Eisenia bicyclis on Macrophages Seung Namkoong 1 , Se-Chan Kang 2 , Hang Do 3 , Ki-Hyo Jang 4 , Seon-A Jang 5 , Myoung-Gun Choung 5 and Eun-Hwa Sohn 5 * 1 Department of Physical Therapy, Kangwon National University, Samcheok 245-907, Korea, 2 Department of Natural Medicine Resources, Semyung University, Jecheon 309-711, Korea, 3 College of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea, 4 Department of Food and Nutrition, 5 Department of Herbal Medicine Resource, Kangwon National University, Samcheok 245-907, Korea Abstract - A large number of edible seaweeds are consumed by the coastal peoples of Asia. Some of them are used in traditional remedies in many parts of the world. In this study we investigated effects of supplementation with ethyl acetate extracts of the brown alga Eisenia bicyclis (EBE) on rat macrophage to evaluate the possibilities as immune-modulators. Twelve male SD rats were divided into two groups and the treatments were as follows: A, no Eisenia bicyclis extract (EBE) intake and distilled water ; B, oral supplemented with EBE 200 mg/kg. After 5 weeks of supplementation, rats were sacrificed to assess the effect on peritoneal macrophage functions. We showed no increasing effects on tumoricidal activity, phagocytic activity and NO production in macrophages in EBE supplementation group. However, EBE supplementation suppressed NO-iNOS production and p65 translocation into the nucleus in LPS-stimulated macrophages. Overall, these results suggest that the supplementation of EBE might have an anti-inflammatory effects on NO-iNOS production in macrophages throughout the inhibition of NF-κB activation. Key words - Eisenia bicyclis, iNOS, Macrophage, Nitric oxide, p65 *Corresponding author. E-mail : ehson@kangwon.ac.kr Introduction Marine environment has been the source of diverse life forms that produce different biologically active compounds. Metabolites from marine plants have been reported to have outstanding biological activities and profound applications in nutraceuticals, cosmeceuticals, and pharmaceuticals. Eisenia bicyclis is a species of the kelp, a member of the brown algae group of seaweeds, best known for its use in Asia. E. bicyclis is high in calcium, iodine, iron, magnesium, and vitamin A as well as being a good dietary source for many other minerals. It has been also known that brown algae extracts closely linked to its protective properties against free radical attack and have anti-oxidant effects (Hu et al., 2010; Kang et al., 2004). They contain the storage polysaccharide laminarin, alginate, fucoxanthin and fucoidan with immunological activities (Joe et al., 2006). Macrophage have been shown to be an important component of host defense against bacterial infection, and cancer (Hahn and Kaufmann, 1981; Verstovsek et al., 1992). Large pools of macrophages, thought to be of mononuclear phagocyte origin, are located throughout the body and historically have been identified by different names including peritoneum (peritoneal macrophages), brain (microglia), bone (osteoclast) and liver (Kupffer cells). In murine/rat peritoneal system, four general stages of activation have been defined and cells in these stages are called resident, inflammatory (or responsive), primed and fully activated macrophages (Klimp et al., 2002). When exposed in vitro LPS and (or) IFN-γ, inflammatory macrophages can develop the capacity to kill tumor cells, and these stages are called fully activated macrophages. During develop other stages, macrophages increase the phagocytic activity and release various materials such as cytokines and reactive intermediates and then carry out nonspecific immune responses (Adams and Hamilton, 1981; Nathan, 1987). Especially, there has been great interest in reactive nitrogen Korean J. Plant Res. 24(3) : 298～303 (2011) Original Research Article