Anti-Inflammatory Effect of Ecklonia cava Extract on Porphyromonas gingivalis Lipopolysaccharide-Stimulated Macrophages and a Periodontitis Rat Model

Ecklonia cava, an edible marine brown alga (Laminariaceae), is a rich source of phlorotannins. This study aimed to investigate the anti-inflammatory effect of Ecklonia cava ethanol extract (ECE, dieckol 10.6%, w/w) on Porphyromonas gingivalis lipopolysaccharide-stimulated inflammation in RAW 264.7 cells and in ligature-induced periodontitis in rats. The levels of nitric oxide (NO) and prostaglandin E(2) were decreased by more than half on treatment with 100 μg/mL ECE. Downregulated tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 gene expression confirmed the anti-inflammatory properties of ECE. ECE treatment upregulated heme oxygenase-1 (HO-1) expression by 6.3-fold and increased HO-1/nuclear factor erythroid 2-related factor 2 (Nrf-2) signaling decreased nuclear factor-κB (NF-κB) translocation. ECE administration (400 mg/kg) significantly reduced gingival index, restricted tooth mobility, and prevented alveolar bone loss (p < 0.05). These beneficial effects were due to decreased inflammatory cell infiltration, IL-1β production, and matrix metalloproteinase expression in gingival tissues. The ratio of receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin, a biomarker of periodontitis and osteolysis, was significantly decreased by ECE administration (p < 0.05). Thus, ECE has potential therapeutic effects for the alleviation of periodontal disease.