Anti-pruritic and anti-inflammatory effects of Sopoongsan on atopic or seborrheic dermatitis: A pilot randomized, placebo-controlled clinical trial and translational research using in vitro and in vivo models

ETHNOPHARMACOLOGICAL RELEVANCE: Sopoongsan (SPS) is widely used in East Asian countries to treat skin diseases such as atopic dermatitis. However, clinical trials on its mechanisms or therapeutic skin effects are lacking. AIM OF THE STUDY: To investigate the efficacy and pharmacological mechanism of SPS for atopic or seborrheic dermatitis and validate related biomarkers in vivo and in vitro. MATERIALS AND METHODS: In this randomized, double-blind, placebo-controlled trial, patients with chronic upper body pruritus diagnosed with atopic or seborrheic dermatitis were administered SPS or placebo for 4 weeks and followed-up for 4 weeks. Itching intensity was assessed using the Numeric Rating Scale. Quality of life was assessed using the Dermatology Life Quality Index and Epworth Sleepiness Scale. Serum concentrations of inflammatory cytokines were determined using enzyme-linked immunosorbent assay to investigate biological mechanisms underlying chronic pruritus. The anti-atopic dermatitis effect and cytokine changes after SPS administration were evaluated in vivo using a mouse model of 1-chloro-2,4-dinitrobenzene-induced atopic dermatitis and in vitro using the HaCaT human epidermal keratinocyte cell line. RESULTS: Of 20 enrolled patients, 10 were randomized into the SPS and placebo groups each. The Numeric Rating Scale score was lower for the SPS than for the placebo group after SPS treatment. Serum RANTES and IL-4 concentrations also decreased. STAT1 inhibition neutralized the effects of SPS on RANTES regulation. CONCLUSIONS: SPS tended to relieve chronic upper body pruritus without obvious adverse effects in patients diagnosed with atopic or seborrheic dermatitis. This therapeutic effect may be related to STAT1 inhibition. TRIAL REGISTRATION NUMBER: KCT0007537.