Isolation and identification of anti-inflammatory compounds from ethyl acetate fraction of Ecklonia stolonifera and their anti-inflammatory action

• DOI: 10.1007/s10811-016-0847-y
• Publication Date: 2016-04-19T16:23:07Z
• Authors: Ran Wei; Min-Sup Lee; Bonggi Lee; Chul-Woong Oh; Chang-Geun Choi; Hyeung-Rak Kim
• Keywords: Anti-inflammatory

Ecklonia stolonifera, a brown alga, has been reported to have several biological activities, including antioxidation, anti-inflammation, and hepatoprotection. This study aims to investigate the anti-inflammatory effect of the ethyl acetate fraction of E. stolonifera (ESA) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. ESA inhibited the production of LPS-induced nitric oxide (NO) and prostaglandin E2 and reduced the expression of inducible nitric oxide synthase and cyclooxygenase-2 in a dose-dependent manner. ESA also inhibited the production of pro-inflammatory cytokines, including tumor necrosis factor α, interleukin (IL)-1β, and IL-6. LPS-induced transcriptional activation of nuclear factor-κB was significantly suppressed by ESA through the prevention of inhibitor κB-α degradation. Eight phlorotannins, including 2-phloroeckol, dioxinodehydroeckol, eckol, phlorofucofuroeckol B, 6,6′-bieckol, dieckol, 974-B, and phlorofucofuroeckol A were isolated from ESA, and their chemical structures were elucidated by NMR spectroscopic analysis. Based on the inhibition of NO production in LPS-treated RAW 264.7 cells, the major anti-inflammatory components in ESA were identified as 2′-phloroeckol, 6,6′-bieckol, phlorofucofuroeckol A, phlorofucofuroeckol B, and 974-B. Our results indicate that E. stolonifera may be considered as a therapeutic agent for the prevention of inflammatory disorders.