Apostichopus japonicus has been used both as a food and in traditional medicine. However, its anti-inflammatory effects in periodontal diseases have not been studied. We examined the anti-inflammatory properties of Apostichopus japonicus extract in RAW 264.7 cells stimulated by Porphyromonas gingivalis. The cytotoxicity of Apostichopus japonicus extract was evaluated using the MTS assay. Its effect on NO production was then measured using the NO assay. The mRNA expression of inducible nitric oxide synthase (iNOS) and the pro-inflammatory cytokines IL-1β and IL-6 were assessed using quantitative real-time PCR (qRT-PCR). Western blotting was performed to investigate the expression of regulatory proteins involved in the NF-κB and MAPK signaling pathways. Apostichopus japonicus extract significantly inhibited NO production without cytotoxicity in RAW 264.7 cells. Following Porphyromonas gingivalis stimulation, treatment with the extract decreased iNOS mRNA expression and protein levels, which are responsible for NO production. The extract also suppressed the mRNA expression of pro-inflammatory cytokines. Additionally, Apostichopus japonicus extract inhibited NF-κB activation by regulating signaling molecules such as IKK and IκBα, while also preventing the phosphorylation of MAPK, including ERK, p38, and JNK, showing anti-inflammatory potential. Therefore, it may be a promising natural candidate for the development of new preventive and therapeutic strategies for periodontitis.

Caulebra okamurae (C. okamurae), a green seaweed, has been reported to exhibit pharmacological properties, including anti-obesity and anti-diabetic effects. This study investigated the anti-inflammatory effects of C. okamurae extracts on periodontal health. The cell viability of RAW 264.7 macrophages was dose-dependently assessed using an MTS assay. The anti-inflammatory activity of C. okamurae on Porphyromonas gingivalis (P. gingivalis)-stimulated RAW 264.7 macrophages was evaluated by measuring nitric oxide (NO) production. mRNA expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β were quantified via quantitative real-time PCR (qRT-PCR). The protein expression of iNOS, p-IKKα/β, p-IκBα, and NF-κB p65 was examined using Western blot and immunofluorescence. The results demonstrated that C. okamurae extracts exhibited no cytotoxicity in RAW 264.7 macrophages at concentrations of 0.2, 2, 20, and 200 μg/mL. The extracts dose-dependently reduced NO production, downregulated mRNA levels of proinflammatory cytokines, and inhibited iNOS expression in P. gingivalis-stimulated RAW 264.7 macrophages, a model commonly used to study periodontal inflammation. Furthermore, the extracts suppressed the phosphorylation of IKKα/β and IκBα and prevented the NF-κB p65 nuclear translocation. These findings suggest that C. okamurae extracts inhibit NF-κB signaling activation triggered by the periodontal pathogen, highlighting their potential anti-inflammatory effects, relevant to periodontal disease.