Atopic dermatitis (AD) and stress create a vicious cycle: stress exacerbates atopic symptoms, and atopic disease elicits stress and anxiety. Targeting multiple pathways including stress and allergic inflammation is, therefore, important for treating AD. In this study, we investigated the remedial value of Polygala tenuifolia Willd. (PTW) for treating immobilization (IMO) stress-exacerbated atopy-like skin dermatitis and its underlying mechanism. Trimellitic anhydride (TMA) was applied to dorsal skin for sensitization and subsequently both ears for eliciting T-cell-dependent contact hypersensitivity in mice, which underwent 2 h-IMO stress and PTW administration for the latter 6 and 9 days in the ear exposure period of TMA, respectively. To elicit in vitro degranulation of human mast cell line-1 (HMC-1), 10 µM substance P (SP) and 200 nM corticotrophin-releasing factor (CRF) were sequentially added with 48 h-interval. PTW extract (500 µg/mL) was added 30 min before CRF treatment. IMO stress exacerbated TMA-induced scratching behavior by 252%, and increased their blood corticosterone levels by two-fold. Treatment with 250 mg/kg PTW significantly restored IMO stress-exacerbated scratching behavior and other indicators such as skin inflammation and water content, lymph node weights, and serum histamine and immunoglobulin E (lgE) levels. Furthermore, it also reversed TMA-stimulated expression of tumor necrosis factor (TNF)-α and interleukin (IL)-4 mRNAs in ear tissues. PTW significantly inhibited SP/CRF-stimulated degranulation of HMC-1 cells, subsequent tryptase secretion, and protein kinase A (PKA) activity. PTW also selectively inhibited p38 mitogen-activated protein kinase (MAPK) phosphorylation in SP/CRF-treated HMC-1 cells. PTW significantly inhibited HMC-1 cell degranulation and alleviated IMO stress-exacerbated atopic dermatitis symptoms by modulating the PKA/p38 MAPK signaling pathway.

Inflammatory bowel disease (IBD) is a major risk factor of colorectal cancer. Drugs currently used for IBD exhibit adverse effects including vomiting, nausea, and diarrhea. Naturally derived novel alternative therapies are required to overcome these limitations. In this study, we investigated the protective effects of ethanol extract of Cicer arietinum (CEE) in a dextran sodium sulfate (DSS)-induced mouse model of colitis. CEE markedly improved DSS-induced clinical symptoms and histological status, such as the disease activity index, spleen weight, and colon length. Moreover, CEE-treated mice showed significant recovery of DSS-induced crypt damage and cell death. CEE suppressed myeloperoxidase (MPO) activity and macrophage marker F4/80 mRNA expression in colonic tissue of mice with DSS-induced colitis, indicating neutrophil infiltration and macrophage accumulation, respectively. Although DSS upregulated pro-inflammatory mediators and activated transcription factors, CEE downregulated the mRNA expression of cytokines including interleukin-6, interleukin-1β, and tumor necrosis factor-α, protein expression of cyclooxygenase-2 and inducible nitric oxide synthase, as well as activation of nuclear factor-kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3). Hence, our findings reveal that the anti-inflammatory properties of CEE, involving the downregulation of the expression of pro-inflammatory mediators by inactivating NF-κB and STAT3 in DSS-induced colitis mice.