Oral Administration of Aster yomena Butanol Fraction Attenuates DNCB-Induced Atopic Dermatitis-like Skin Inflammation in Mice: Implications as a Dietary Supplement Candidate for Companion Animals

Atopic dermatitis (AD) is a chronic inflammatory skin disease requiring long-term management in companion animals. This study evaluated the butanol fraction of Aster yomena extract (AY BuOH) as an orally administered dietary supplement candidate for atopic skin health using a DNCB-induced AD-like mouse model. AY BuOH was chemically profiled by UPLC-ESI-QToF-MS/MS and quantified for major marker compounds. Male SKH-1 mice were allocated to normal control, DNCB control, oclacitinib-treated, or AY BuOH-treated groups (2.5–640 mg/kg/day) for five weeks. AY BuOH contained abundant rutin and dicaffeoylquinic acid (DCQA) isomers, including 3,4-, 3,5-, and 4,5-DCQA isomers. Oral AY BuOH administration, particularly at intermediate doses, reduced modified dermatitis severity scores, gross skin lesions, serum immunoglobulin E levels, and cutaneous interleukin-4 and interleukin-13 concentrations, with effects comparable to those observed in the oclacitinib reference group in selected endpoints. AY BuOH also partially restored splenic Th1/Th2 balance and attenuated epidermal and dermal thickening. The highest dose, 640 mg/kg/day, was associated with body weight loss and elevated hepatic enzyme activities, suggesting potential hepatic stress. These findings provide preclinical evidence that AY BuOH may serve as a standardized plant-derived dietary supplement or functional feed additive candidate for companion animal skin health, pending target-species safety and efficacy validation.