title: 8,8'-Bieckol, isolated from edible brown algae, exerts its anti-inflammatory effects through inhibition of NF-κB signaling and ROS production in LPS-stimulated macrophages.
abstract: Ecklonia cava (E. cava) is an abundant brown alga that contains high levels of phlorotannins, which are unique marine polyphenolic compounds. It has been suggested that E. cava phlorotannins exert anti-inflammatory effects. However, the anti-inflammatory effects and underlying molecular mechanism exerted by 8,8'-bieckol isolated from E. cava have not been reported. Thus, in this study, we examined the anti-inflammatory effects of 8,8'-bieckol on lipopolysaccharide (LPS)-stimulated primary macrophages and RAW 264.7 macrophages. We found that 8,8'-bieckol suppressed key inflammatory mediator [i.e., nitric oxide (NO) and prostaglandin E2 (PGE2)] production in both primary and RAW 264.7 macrophages. 8,8'-Bieckol inhibited NO by suppressing LPS-induced expression of inducible nitric oxide synthase (iNOS) at the mRNA and protein levels in primary macrophages and RAW 264.7 cells. In addition, 8,8'-bieckol decreased the production and mRNA expression of the inflammatory cytokine interleukin-6 (IL-6), but not tumor necrosis factor (TNF)-α, in RAW 264.7 cells. Moreover, 8,8'-bieckol treatment diminished transactivation of nuclear factor-kappa B (NF-κB) and nuclear translocation of the NF-κB p65 subunit and suppressed LPS-induced intracellular reactive oxygen species (ROS) production in macrophages. Furthermore, 8,8'-bieckol markedly reduced mortality in LPS-induced septic mice. Taken together, these data indicate that the anti-inflammatory properties of 8,8'-bieckol are associated with the suppression of NO, PGE2, and IL-6 via negative regulation of the NF-κB pathway and ROS production in LPS-stimulated RAW 264.7 cells. Moreover, 8,8'-bieckol protects mice from endotoxin shock.
authors.affiliation: Department of Life & Nanopharmaceutical Science, Kyung Hee University, Seoul, South Korea; Department of Oriental Pharmaceutical Science, Kyung Hee University, Seoul, South Korea.
authors.forename: Yeong-In
authors.initials: YI
authors.lastname: Yang
authors.affiliation: Department of Life & Nanopharmaceutical Science, Kyung Hee University, Seoul, South Korea; Department of Oriental Pharmaceutical Science, Kyung Hee University, Seoul, South Korea.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Jung
authors.affiliation: Department of Life & Nanopharmaceutical Science, Kyung Hee University, Seoul, South Korea.
authors.forename: Kyung-Tae
authors.initials: KT
authors.lastname: Lee
authors.affiliation: Department of Life & Nanopharmaceutical Science, Kyung Hee University, Seoul, South Korea; Department of Oriental Pharmaceutical Science, Kyung Hee University, Seoul, South Korea. Electronic address: jchoi@khu.ac.kr.
authors.forename: Jung-Hye
authors.initials: JH
authors.lastname: Choi
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002470:Cell Survival; D015232:Dinoprostone / Q000235:genetics / Q000378:metabolism; D004147:Dioxins / Q000737:chemistry / Q000494:pharmacology*; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000633:toxicity; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D015394:Molecular Structure; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D009569:Nitric Oxide / Q000378:metabolism; D000459:Phaeophyceae / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004147:Dioxins; D015850:Interleukin-6; D008070:Lipopolysaccharides; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; C062362:8,8'-bieckol; D015232:Dinoprostone
keywords: 8,8′-Bieckol; Ecklonia cava; IL-6; NF-κB; ROS; iNOS