Huanglian ointment alleviates eczema by maintaining the balance of c-Jun and JunB and inhibiting AGE-RAGE-mediated pro-inflammation signaling pathway

Huanglian ointment exhibits clinical efficacy for repairing skin barriers and inhibiting skin inflammation, and has been used to ameliorate eczema for many years. However, the active components and mechanism of Huanglian ointment have not yet been elucidated. This study aimed to demonstrate the main active components and molecular mechanisms of Huanglian ointment for the treatment of eczema. The main active components of Huanglian ointment were identified by gas chromatography-mass spectrometry. Network pharmacology approach and molecular docking techniques to predict the potential molecular mechanisms of Huanglian ointment alleviating eczema. Furthermore, Biostir-AD®-induced guinea pigs and tumor necrosis α (TNF-α)/interferon γ (IFN-γ)-induced HaCaT cells were employed to investigate the effectiveness and mechanisms of Huanglian ointment using histopathological staining, enzyme-linked immunosorbent assay, MTT assay, and western blot analysis. Fourteen chemistry components were identified in Huanglian ointment. In total, 78 intersecting gene targets were identified between Huanglian ointment and eczema, including Jun, inflammatory regulators, and chemokine factors. Intersecting gene targets were enriched for cytokine and chemokine receptor binding, and inflammatory related signaling pathways. The molecular docking results showed that the identified components had a stable binding conformation with core targets. In vivo experiments showed that Huanglian ointment markedly ameliorated eczema-like skin lesions, restored histopathological morphology, and decreased levels of TNF-α, IFN-γ, and interleukin 6. Moreover, Huanglian ointment effectively protected HaCaT cells against TNF-α/IFN-γ-induced cell death and overproduction of thymus- and activation-regulated chemokine, macrophage-derived chemokine, and regulated upon activation normal T cell-expressed and secreted factor. Subsequently, we found that Huanglian ointment repaired skin barriers by affecting c-Jun, JunB, and filaggrin expression, and suppressed inflammatory response by inhibiting AGE-RAGE signaling pathway, both in vivo and in vitro. Our results demonstrated that Huanglian ointment repaired skin barriers and inhibited inflammation by maintaining the balance of c-Jun and JunB, and suppressing AGE-RAGE signaling pathway, thereby relieving eczema. These findings providing a molecular basis for treatment of eczema by Huanglian ointment.