Smilacis Chinae Rhizoma ethyl acetate fraction alleviates IMQ-induced psoriasis by inhibiting IL-17-driven T-cell immune responses.

ETHNOPHARMACOLOGICAL RELEVANCE: Smilacis Chinae Rhizoma (SCR), derived from the rhizome of Smilax china L., has long been utilized in traditional Chinese medicine for the treatment of inflammatory dermatological disorders, including cutaneous abscesses.

AIM OF THE STUDY: This study aimed to evaluate the therapeutic potential and underlying mechanisms of Smilacis Chinae Rhizoma ethyl acetate fraction (SCR-EA) in psoriasis, with a focus on its immunomodulatory effects on T-cell responses and the IL-17 signaling pathway.

MATERIALS AND

METHODS

A psoriasis-like mouse model was induced via topical imiquimod (IMQ) application. Mice were treated with SCR-EA (100 or 200 mg/kg) or methotrexate (MTX, 1 mg/kg). Psoriasis severity was assessed using the Psoriasis Area and Severity Index (PASI). Histopathological alterations, KC proliferation, and inflammatory cytokine mRNA levels (IL-6, TGF-β1, IL-1β, S100A9) were analyzed. T-cell subset distribution in the spleen was examined by flow cytometry. Key IL-17 pathway proteins (IL-17A, RORγt, p-STAT3, STAT3) were assessed by Western blot. Network pharmacology and molecular docking were used to predict potential targets and pathways, followed by experimental validation.

RESULTS

SCR-EA significantly alleviated IMQ-induced psoriatic lesions, reduced epidermal thickness, and inhibited KC hyperproliferation. It suppressed pro-inflammatory cytokine expression and corrected the IMQ-induced imbalance of Th1, Th2, and Th17 cell subsets in the spleen. Network pharmacology identified the IL-17 signaling pathway as a major target, which was validated by SCR-EA's inhibition of IL-17A, RORγt, and STAT3 activation. Molecular docking revealed strong binding affinities between SCR-EA's primary constituents (astilbin, engeletin, resveratrol) and IL-6 and TNF-α.

CONCLUSION

SCR-EA mitigates IMQ-induced psoriasis by modulating T-cell differentiation and inhibiting the IL-17 signaling pathway. This study provides a pharmacological foundation for the traditional use of SCR in treating inflammatory skin conditions and positions SCR-EA as a promising multi-target candidate for psoriasis therapy.