Inhibitory Effect of Methyleugenol on IgE‐Mediated Allergic Inflammation in RBL‐2H3 Cells

Abstract

Allergic diseases, such as asthma and allergic rhinitis, are common. Therefore, the discovery of therapeutic drugs for these conditions is essential. Methyleugenol (ME) is a natural compound with antiallergic, antianaphylactic, antinociceptive, and anti-inflammatory effects. This study examined the antiallergic effect of ME on IgE-mediated inflammatory responses and its antiallergy mechanism in the mast cell line, RBL-2H3. We found that ME significantly inhibited the release of β-hexosaminidase, tumor necrosis factor- (TNF-) α, and interleukin- (IL-) 4, and was not cytotoxic at the tested concentrations (0–100 μM). Additionally, ME markedly reduced the production of the proinflammatory lipid mediators prostaglandin E2 (PGE2), prostaglandin D2 (PGD2), leukotriene B4 (LTB4), and leukotriene C4 (LTC4). We further evaluated the effect of ME on the early stages of the FcεRI cascade. ME significantly inhibited Syk phosphorylation and expression but had no effect on Lyn. Furthermore, it suppressed ERK1/2, p38, and JNK phosphorylation, which is implicated in proinflammatory cytokine expression. ME also decreased cytosolic phospholipase A2 (cPLA2) and 5-lipoxygenase (5-LO) phosphorylation and cyclooxygenase-2 (COX-2) expression. These results suggest that ME inhibits allergic response by suppressing the activation of Syk, ERK1/2, p38, JNK, cPLA2, and 5-LO. Furthermore, the strong inhibition of COX-2 expression may also contribute to the antiallergic action of ME. Our study provides further information about the biological functions of ME.

Anti-allergic and anti-atopic dermatitis effects of Gardenia Fructus extract

“…The release of inflammatory mediators and cytokines from immune cells has been implicated in Type-I allergy. Further, it is reported that TNF-α and COX-2 play an important role in AD like allergic responses (Fogh, Herlin, & Kragballe, 1989;Tang et al, 2015). Here, we found that GFE inhibited the production of COX-2 and TNF-α in stimulated RBL-2H3 cells (Figure 2(A)).…”

“…After synthesis, β-hexosaminidase is stored in secretory granules and released into the extracellular medium during degranulation. RBL-2H3 cells were grown in 24-well plates (2.5 × 10 6 cells per well) and were sensitized overnight with 10 μg/mLof DNP-IgE (Tang et al, 2015). Next, the growth medium was replaced with modified Siraganian buffer (119 mmol/L NaCl, 5 mmol/L KCl, 1 mmol/L CaCl 2 , 0.4 mmol/L MgCl 2 , 25 mmol/L PIPES, 5.6 mmol/L glucose, 40 mmol/L NaOH, and 0.1% [w/v] BSA, pH 7.2).…”

Xiao Qing Long Tang essential oil exhibits inhibitory effects on the release of pro-inflammatory mediators by suppressing NF-κB, AP-1, and IRF3 signalling in the lipopolysaccharide-stimulated RAW264.7 cells

“…26 Methyleugenol has been demonstrated to reduce the IgE-mediated allergic inammation in mast cells. 27 Camphene has been reported to inhibit the LPS-induced TNF-a production in the RAW264.7 macrophages. 28 a-Terpineol suppresses the production of inammatory mediators in LPS-stimulated human macrophages by regulating NF-kB and MAPKs.…”

Inhibitory Effects of Angelica Polysaccharide on Activation of Mast Cells

“…Subsequently, several of proinflammatory cytokines and allergic mediators are released, leading to immune response. Histamine and β -hexosaminidase are commonly considered as the notable markers in degranulation of mast cells [ 17 ]. Previous reports have demonstrated that they would be elevated in plasma or tissues in various allergic diseases.…”