Qingre Qushi formula suppresses atopic dermatitis via a multi-target mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: Our previous studies have shown that the Qingre Qushi (QRQS) formula can treat atopic dermatitis (AD), and its possible mechanism is related to the regulation of the IL-33/ST2 signaling pathway. However, the molecular mechanism of AD is complex, and various AD subtypes respond better to therapies aimed at distinct targets.

AIM OF THE STUDY: This study aimed to investigate the multi-target mechanism of QRQS using experimental and network pharmacology studies.

MATERIALS AND METHODS: Flaky tail (FT) mice were treated with different concentrations of QRQS and cetirizine. The dermatitis score, scratching frequency, and histological evaluation were normatively evaluated. The levels of IgE and IgG1 in serum were tested using ELISAs. Using ELISA and RT-PCR, the expression of associated cytokines was determined. IL-17A-stimulated HaCaT cells were treated with QRQS to assess mRNA and protein expression. To elucidate the mechanism, a network pharmacology analysis based on active components derived from UPLC was conducted. Through molecular docking, we evaluated the binding affinity between the active constituents of QRQS and potential targets.

RESULTS: Using UPLC, 177 active ingredients in QRQS were identified. Network pharmacology analysis showed that the anti-AD effect of the active ingredients was related to the IL-17 signaling pathway and its related targets. FT mice are characterized by Th17-dominated immune disorders. QRQS ameliorated AD-like symptoms and decreased dermatitis scores and scratching frequencies. After QRQS treatment, IL-17A expression was inhibited and IL-17 pathway-associated cytokines were downregulated. Along with changes in Th17-differentiation, QRQS suppressed the expression of IL-4, IL-13, and TNF-α. QRQS also decreased the expression of IL-6, IL-8, and COX-2 in HaCaT cells exposed to IL-17A. The anti-AD active doses are 3.86 g/kg/day in vivo and 100 μg/mL in vitro.

CONCLUSION: QRQS has a multi-target immunoregulatory effect on AD and can improve the Th17-dominated inflammatory response by regulating the IL-17A signaling pathway. Quercetin, genistein, luteolin, and kaempferol are potential active ingredients.