Appl Biochem Biotechnol (2014) 173:957–967 DOI 10.1007/s12010-014-0910-6
Suppression of NF-κB by Dieckol Extracted from Ecklonia cava Negatively Regulates LPS Induction of Inducible Nitric Oxide Synthase Gene Hye-Jin Choi & Jung-Hwan Park & Bong Ho Lee & Hee Youn Chee & Kyung Bok Lee & Sang-Muk Oh
Received: 14 January 2014 / Accepted: 7 April 2014 / Published online: 18 April 2014 # Springer Science+Business Media New York 2014
Abstract Dieckol, extracted from brown algae, Ecklonia cava, is suggested to elicit antiinflammatory or anti-tumorigenic activities. However, dieckol-mediated regulatory mechanism for inflammatory response still remains elusive. Here, we show that dieckol suppressed lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) expression in mouse leukemic macrophage Raw264.7 cells. Also, dieckol decreased LPS-induced both nitric oxide (NO) production and iNOS promoter-driven transcriptional activity in a dose-dependent manner. On the other hand, LPS-mediated NF-κB activity was inhibited by dieckol treatment. Moreover, results revealed that dieckol diminished LPS-mediated p65 nuclear translocation or IκBα phosphorylation dose-dependently, and reduced LPS-induced phosphorylation of mitogen-activated protein kinases (MAPKs), significantly p38MAPK. Collectively, these findings suggest that dieckol acts as a negative regulator of LPS-mediated iNOS induction through suppression of NF-κB activity, implying a mechanistic role of dieckol in regulation of inflammatory response. Keywords Dieckol . LPS . NF-κB . iNOS . MAPK
Introduction Brown algae, composed of polysaccharide and polyphenols, are abundant in foods of East Asia and known to exert medicinal effects due to active polyphenolic components . H.