Ethyl acetate fraction of Abeliophyllum distichum Nakai alleviates atopic dermatitis-like symptoms in vivo and in vitro model

Abeliophyllum distichum Nakai (ADN), a plant unique to Korea, has demonstrated anti-aging, liver-protective, and anti-inflammatory effects in various studies. Based on these findings, ADN extracts are proposed to offer benefits against allergic reactions and inflammation, including potential effects on atopic dermatitis (AD) induced by 1-chloro-2,4-dinitrobenzene (DNCB) in vivo and on keratinocytes and mast cells in vitro. To investigate the effect of the ADN-ethyl acetate (ADN-EA) extract, cells were pre-treated with ADN-EA, after which HaCaT cells were stimulated with TNF-α/IFN-γ, HMC-1 cells with PMA and A23187, and RPMCs with compound 48/80. Cytokine levels were analyzed with ELISA and PCR. ADN-EA efficacy in the DNCB-AD model was assessed by SCORAD, scratching behavior, IgE and cytokine levels in blood, and inflammatory cell infiltration in skin lesions using histology and immunohistochemistry. Effects of ADN-EA on the MAPK and STAT pathways in skin lesions were analyzed by western blotting. In vitro , ADN-EA decreased GM-CSF, MCP-1, and IL-1β in HaCaT cells, GM-CSF, MCP-1, TNF-α, and IL-6 in HMC-1 cells, and inhibited histamine release in RPMCs. In vivo, ADN-EA reduced AD symptoms, SCORAD, scratching behavior, inflammatory cell infiltration, and epidermal and dermal thickness. It also significantly inhibited MAPK and STAT1 phosphorylation. These results indicate that ADN-EA may alleviate allergic inflammation by modulating the MAPK and STAT1 signaling pathways, suggesting its potential as a therapeutic option for managing AD.