Anti-Atopic Effect of Acorn Shell Extract on Atopic Dermatitis-Like Lesions in Mice and Its Active Phytochemicals

To investigate the potential effects of acorn shells on atopic dermatitis (AD), we utilized oxazolone (OX)- or 2,4-dinitrochlorobenzene (DNCB)-induced AD-like lesion mouse models. Our research demonstrates that Acorn shell extract (ASE) improved the progression of AD-like lesions, including swelling, which were induced by oxazolone on Balb/c mouse ears. Additionally, ASE significantly decreased the ear thickness (OX: 0.42 +/- 0.01 mm, OX-ASE: 0.32 +/- 0.02 mm) and epidermal thickness (OX: 75.3 +/- 32.6 mu m, OX-ASE: 46.1 +/- 13.4 mu m). The continuous DNCB-induced AD mouse model in SKH-1 hairless mice demonstrated that ASE improved AD-like symptoms, including the recovery of skin barrier dysfunction, Immunoglobulin E hyperproduction (DNCB: 340.1 +/- 66.8 ng/mL, DNCB-ASE: 234.8 +/- 32.9 ng/mL) and an increase in epidermal thickness (DNCB: 96.4 +/- 21.9 mu m, DNCB-ASE: 52.4 +/- 16.3 mu m). In addition, we found that ASE suppressed the levels of AD-involved cytokines, such as Tumor Necrosis Factor alpha, IL-1 beta, IL-25 and IL-33 in both animal models. Furthermore, gallic acid and ellagic acid isolated from ASE suppressed beta-hexosaminidase release and IL-4 expression in RBL-2H3 cells. The acorn shell and its active phytochemicals have potential as a new remedy for the improvement of atopic dermatitis and other inflammatory diseases.