Seaweed has been used in traditional cosmetics and as a herbal medicine in treatments for cough, boils, goiters, stomach ailments, and urinary diseases, and for reducing the incidence of tumors, ulcers, and headaches. Despite the fact that seaweeds are frequently used in the practice of human health, little is known about the role of seaweed in the context of inflammation. This study aimed to investigate the influence of Jeju endemic seaweed on a mouse macrophage cell line (RAW 264.7) under the stimulation of lipopolysaccharide (LPS). Ethyl acetate extracts obtained from 14 different kinds of Jeju seaweeds were screened for inhibitory effects on pro-inflammatory mediators. Our results revealed that extracts from five seaweeds, Laurencia okamurae, Grateloupia elliptica, Sargassum thunbergii, Gloiopeltis furcata, and Hizikia fusiformis, were potent inhibitors of the production of pro-inflammatory mediators such as nitric oxide (NO), prostaglandin E 2 (PGE 2 ), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Based on these results, the anti-inflammatory effects and low cell toxicity of these seaweed extracts suggest potential therapeutic applications in the regulation of the inflammatory response.

As part of our ongoing alternative medicine program, we have directed our attention toward the identification of edible seaweeds in Korea. Here we report on the anti-inflammatory activities of Ecklonia stolonifera. The present study was undertaken to elucidate the pharmacological and biological effects of E. stolonifera extracts on the production of inflammatory mediators in macrophages. The results indicate that the hexane fraction of E. stolonifera extract (ESH) is an effective inhibitor of lipopolysccharide (LPS)-induced NO, prostaglandin E2, and proinflammatory cytokine production in RAW 264.7 cells. These inhibitory effects of ESH were accompanied by decreases in the expression of inducible nitric oxide synthase and cyclooxygenase-2 proteins. Furthermore, ESH inhibited the LPS-induced phosphorylation and degradation of IκB-α, which is required for the nuclear translocations of the p50 and p65 nuclear transcription factor kappa-B (NF-κB) subunits in RAW 264.7 cells. Our results suggest that ESH might exert an anti-inflammatory effect by inhibiting the expression of pro-inflammatory cytokines. Such an effect is mediated by a blocking of NF-κB activation, which consequently inhibits the generation of inflammatory mediators in RAW264.7 cells. Through HPLC fingerprinting of the E. stolonifera extract, the phloroglucinol was also identified and quantified as standard substance. Moreover, we tested the potential application of E. stolonifera extract as a cosmetic material by performing human skin primary irritation tests. In these assays, E. stolonifera extracts did not induce any adverse reactions. Based on these results, we suggest that E. stolonifera extracts be considered possible anti-inflammatory candidates for topical application.