###### Abstract
After being translocated into the nucleus, NF-\(\kappa\)B dimers bind to its target DNA elements and then stimulate the transcription of genes responsible for inflammation [8; 9; 10]. On the other hand, mitogen-activated protein kinases (MAPK) are an evolutionarily preserved family of enzymes capable of forming an integrated network required to complete important cell functions such as apoptosis, cell differentiation, and cell proliferation [11]. ERK1/2, JNK, and p38 are three known MAPKs involved in inflammatory gene regulation. To date, it has been reported that the MAPK kinase (MKK)1 and MKK-2 are involved in activating ERK1/2, MKK3, MKK4, and MKK6 in p38 MAPK activation; MKK4 and MKK7 are involved in the activation of JNK [12]. Inflammatory stimuli such as bacteria, fungi, and dust activate macrophages through the receptors located in the cell membrane. Furthermore, the activation of the MAPK pathway up-regulates the production of tumor necrosis factor alpha (TNF-\(\alpha\)), Interleukin (IL)-6, IL-8, and IL-18; known bio-markers of chronic inflammatory symptoms [13]; therefore, the compounds that are capable of inhibiting or down-regulating NF-\(\kappa\)B and MAPK-related proteins might have the potential to be developed as anti-inflammatory drugs. _Sargassum horneri_ (Fucales, Phaeophyceae) is an invasive brown seaweed, which abundantly grows in the subtidal zone as an annual species along with the coastal areas of Korea, Japan, and China [14]. From November to March _S. horneri_ grows rapidly and reaches up to 7 m in length [15]. _S. horneri_ is also rich in essential vitamins, amino acids, and polysaccharides. In addition, it has been considered a medicinal ingredient in traditional folk medicine for centuries in the East-Asia region [16; 17]; however, _S. horneri_ has been identified as an invasive brown seaweed species in coastal areas of Jeju island and southern coastlines of South Korea [18]. Previous studies have reported that the large amounts of biomass accumulated around the shallow coastal areas of South Korea negatively affected the aquaculture and fisheries industries in Korea [18; 19]; thus, effective utilization methods are required to remove drifting biomass of _S. horneri_ in a cost-effective method. As far as we understand, using _S. horneri_ as an industrial level raw material is one possible approach to effectively controlling this seaweed; however, before we can achieve this,many research studies are required to determine the suitability of _S. horneri_ as a functional ingredient for industrial applications. Furthermore, our previous studies demonstrated the protective effects of ethanolic extract separated from _S. horneri_ against UPM-induced inflammatory responses using in vivo and in vitro models. According to our observations, _S. horneri_ down-regulated the activation of the TLR-mediated downstream activation of MAPKs and NF-\(\kappa\)B, and consequent inflammatory symptom development in murine models and lung macrophages [20; 21]; however, the identification and characterization of the active compounds responsible for the aforementioned activities are important to formulate functional foods and nutraceuticals; therefore, we attempted to determine the anti-inflammatory mechanisms associated with 3-hydroxy-5,6-epoxy-\(\beta\)-ionone isolated from _S. horneri_ against UPM-exposed mouse lung macrophages.