Abstract. Background

Background/Aim: Periodontitis is a chronic inflammatory disease linked to various systemic age-related conditions. It is known that α,β-unsaturated carbonyl compounds such as dietary cinnamates (β-phenyl acrylates) and related (meth)acrylates can have various positive and negative health effects, including cytotoxicity, allergic activity, pro-and anti-inflammatory activity, and anticancer activity. To clarify the anti-inflammatory properties of α,β-unsaturated carbonyl compounds without a phenolic group in the context of periodontal tissue inflammation and alveolar bone loss, we investigated the cytotoxicity and up-regulatory/downregulatory effect of three trans-cinnamates (trans-cinnamic acid, methyl cinnamate, trans-cinnamaldehyde), two acrylates (ethyl acrylate, 2-hydroxyethyl acrylate), and three methacrylates (methyl methacrylate, 2-hydroxyethyl methacrylate, and triethyleneglycol dimethacrylate) using RAW264.7 cells. Materials and Methods: Cytotoxicity was determined using a cell counting kit (CCK-8) and mRNA expression was determined using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Proinflammatory and anti-inflammatory properties were assessed in terms of expression of mRNAs for cyclo-oxygenase-2 (Cox2), nitric oxide synthase 2 (Nos2), tumor necrosis factoralpha (Tnfa) and heme oxygenase 1 (Ho1). Results: The most cytotoxic compound was 2-hydroxyethyl acrylate, followed by ethyl acrylate and cinnamaldehyde (50% lethal cytotoxic concentration, LC 50 =0.2-0.5 mM). Cox2 mRNA expression was up-regulated by cinnamaldehyde and 2-hydroxyethyl acrylate, particularly by the former. In contrast, the upregulatory effect on Nos2 mRNA expression was in the order: cinnamaldehyde >> ethyl acrylate ≈ triethyleneglycol dimethacrylate >> methyl methacrylate ≈ methyl cinnamate. On the other hand, cinnamic acid and 2-hydroxyethyl methacrylate had no effect on gene expression. The two acrylates, but not cinnamates and methacrylates, up-regulated the expression of Ho1 mRNA at a non-cytotoxic concentration of 0.1 mM. Expression of Cox2, Nos2 and Tnfa mRNAs induced by Porphyromonas gingivalis lipopolysaccharide was greatly suppressed by cinnamaldehyde, methyl cinnamate and the two acrylates at 0.1 mM (p<0.05), and slightly, but significantly suppressed by cinnamic acid and methacrylates at 0.

Background/Aim: α,β-Unsaturated ester monomers such as methyl methacrylates (MMA), 2-hydroxyethyl methacrylates (2-HEMA), ethyleneglycol dimethacrylate (EGDMA) and triethyleneglycol dimetacrylate (TEGDMA) have been widely used in dentistry as dental materials. The present study was designed to clarify the proinflammatory activity of monomers. Materials and Methods: The cytotoxicity of the monomers and their effects on the expression of cyclooxygenase-2 (Cox2), nitric oxide synthase 2 (Nos2) and heme oxygenase 1 (Ho-1) mRNAs in RAW264.7 cells were determined using a cell counting kit and real-time reverse transcriptase-polymerase chain reaction, respectively. Results: The cytotoxicity declined in the order n-butyl acrylate (nBA) > acrylic acid > TEGDMA > EGDMA > methacrylic acid ≈ 2-HEMA > lauryl methacrylate > nBMA > MMA. nBA and EGDMA at 1 mM up-regulated the expression of Cox2 mRNA. In contrast, 1 mM nBA and 10 mM 2-HEMA up-regulated the expression of Nos2 mRNA. Up-regulation of Ho-1 mRNA expression was found for 0.1 mM nBA, 1 mM EGDMA and 2 mM TEGDMA. The electrophilicity, ω was calculated on the basis of the density function theory BLYP/6-31G*. Conclusion: nBA and EGDMA with high ω values exerted potent proinflammatory activities. nBA, EGDMA and TEGDMA upregulated Ho-1 gene expression. Ho-1 gene activation of monomers may promote resistance of chemical carcinogenesis in biological systems.

Background/Aim: Microbial tetracycline (TC) pastes have been employed to treat oral bacterial infection. In the present study, we investigated the kinetic radicalscavenging and pro-/anti-inflammatory activity of TC with or without visible light irradiation (VLI). Materials and Methods: The radical-scavenging activity of TC and minocycline (MC) was determined by differential scanning calorimetry (DSC). The stoichiometric factor (n) and the rate constant of inhibition and propagation (k inh /k p) were determined. The levels of cyclooxygenase-2 (Cox2), tumor necrosis factor-α (Tnfα) or nitric oxide synthase 2 (Nos2) mRNA in RAW264.7 cells stimulated with lipopolysaccharide (LPS) were investigated using real-time reverse transcriptasepolymerase chain reaction. Results: The n and k inh /k p values for 1 mM TC in 2,2'-azobisisobutyronitrile and benzoyl peroxide systems were 0.1-0.2 and 119-250, respectively, whereas the corresponding values for quercetin (QU) and resveratrol (RE) were 2-4 and 7-15, respectively. In RAW264.7 cells stimulated with LPS, Cox2 and Tnfα mRNA were over-expressed in the presence of TC. MC downregulated only the expression of Cox2 by about 50% in LPSstimulated cells. The anti-inflammatory activity determined on the basis of Cox2 inhibition declined in the order QU>RE>MC>TC. Upon application of VLI, only TC downregulated the expression of LPS-stimulated Cox2 and Tnfα mRNA. After exposure to VLI, TC, but not MC, markedly up-regulated hemoxygenase-1 (Ho-1) expression. Conclusion: TC is a chain-breaking antioxidant with a large k inh. Upon activation by VLI, TC may undergo degradation and its degradation products affect pleiotropic mediators such as Cox2, Tnfα and Ho-1. TC may be useful as a local photodynamic therapy for periodontal diseases.

Abstract. Background Conclusion: Most eugenol-related compounds had proinflammatory activity at high concentrations. However, they had also anti-inflammatory activity at lower concentrations. Eugenol-related compounds may exert antioxidant and anti-inflammatory activity in LPS-stimulated RAW264.7 cells possibly by inhibiting the activation of nuclear factor-kappa B (Nf-ĸB), whereas bis-eugenol requires induction of HO-1 expression. bis-Eugenol as well as curcumin, may have anti-inflammatory and anticancer therapeutic applications.Eugenol-related compounds are known to have antioxidant, anti-inflammatory, antiviral, antifungal, antibacterial, anticancer, antidiabetic and neuroprotective properties (1-3). We have previously shown that the biphenols curcumin, biseugenol, magnolol and honokiol exert antioxidant effects and also inhibit the up-regulation of cyclooxygenase-2 (Cox-2) mRNA expression elicited by lipopolysaccharide (LPS) and Porphyromonas gingivalis fimbriae (PGF) (4, 5). We have also shown that the prooxidant activity of eugenol, isoeugenol and curcumin is inhibited by visible light irradiation and treatment with horseradish peroxidase, suggesting that these compounds elicit production of intracellular reactive oxygen species (ROS) under prooxidative conditions (6-8). Interestingly, low and physiological levels of ROS are required for normal physiological activity in cells, whereas high levels of ROS promote cytotoxicity, apoptosis, and inflammatory activity. A high level of ROS modulates a number of cell signaling pathways, and regulates the expression of multiple genes such as Cox-2 and nitric oxide synthase (Nos) 2 in vitro and in vivo 819