Sulfuretin alleviates atopic dermatitis-like symptoms in mice via suppressing Th2 cell activity

Atopic dermatitis (AD) is a chronic skin inflammatory disease characterized by uncontrolled Th2 cells response to environmental allergens. Long-term topical application of corticosteroids for treating AD may induce severe side effects. Sulfuretin is a major flavonoid found in Rhus verniciflua and carries antioxidant and anti-inflammatory properties. Its therapeutic effect on AD has not been characterized. We first studied the cytotoxic and regulatory effects of sulfuretin on differentiated Th2 cells. Next, we evaluated therapeutic effect of sulfuretin on AD-like damages caused by 2,4-dinitrochlorobenzene (DNCB) in a mouse model. Serum IgE level, overall symptomatic score, and cytokine accumulation at the lesions were measured. Lastly, we investigated the regulatory mechanism of sulfuretin on GATA3 pathway in primary mouse CD4⁺ cells. Study on in vitro differentiated Th2 cells showed sulfuretin inhibited IL4 production in dose-dependent manner without any cytotoxicity. In vivo study showed 10 μM sulfuretin alleviated the AD symptoms including skin lesion severity, scratching incidence, IgE serum level, and proinflammatory cytokine accumulation at local skin lesion site. Mechanistic study suggested sulfuretin attenuated Th2 cytokine production by suppressing GATA3 expression. Our results demonstrate that sulfuretin could be used as therapeutic application for treating AD.