Chaga Mushroom ( <i>Inonotus obliquus</i> ) Attenuates DNCB-Induced Atopic Dermatitis by Modulating Oxidative Stress and Cytokine Expression

Recent studies highlight the immunomodulatory properties of Chaga mushrooms. Atopic dermatitis (AD) is a multifactorial skin disorder involving interactions between innate and adaptive immune responses. This investigation evaluates the anti-atopic dermatitis activity of a by-product from ethanol-extracted Chaga mushroom (E-CME), positioning it as a sustainable natural candidate for AD therapeutic development. The antioxidant potential of E-CME was assessed using DPPH radical scavenging, H₂O₂ scavenging, metal chelation, and FRAP assays. <i>In vitro</i>, its immunomodulatory effects were evaluated in HaCaT and RBL-2H3 cell lines by measuring cytokine release and β-Hexosaminidase activity. For <i>in vivo</i> analysis, E-CME was topically applied to BALB/c mice sensitized with Dermatophagoides farinae extract (DFE), with AD induced by DNCB. Post-treatment, inflammatory cytokine expression and MAPK marker expression were examined. E-CME treatment significantly improved dermatitis scores (<i>p</i> < 0.05), mast cell infiltration, serum immunoglobulin levels (24.07% increase of IgG2, 26.19% decrease of IgE), oxidative stress markers, and skin cytokine gene expression. Spleen and lymph node weights, plus splenocyte viability, also improved with E-CME treatment. These findings suggest that E-CME possesses substantial therapeutic potential for AD management, attributed to its antioxidant and immunomodulatory effects, possibly mediated by the inhibition of oxidative stress-associated inflammatory pathways.