Effects of Xanthium stramarium and Psoralea corylifolia Extracts Combined with UVA1 Irradiation on the Cell Proliferation and TGF-β1 Expression of Keloid Fibroblasts

BACKGROUND: Xanthium stramarium (XAS) and Psoralea corylifolia (PSC), phototoxic oriental medicinal plants, has been used in traditional medicines in Asian countries. OBJECTIVE: The effects of highly purified XAS or PSC extract combined with ultraviolet A1 (UVA1) irradiation on cell proliferation and transforming growth factor-beta1 (TGF-β1) expression of the keloid fibroblast were being investigated to define potential therapeutic uses for keloid treatments. METHODS: The keloid fibroblasts were treated with XAS or PSC alone or in the combination with UVA1 irradiation. The cell viability, apoptosis, and expression of TGF-β1 and collagen I were investigated. RESULTS: XAS and PSC in combination with UVA1 irradiation suppressed cell proliferation and induced apoptosis of keloid fibroblasts. Furthermore, the XAS and PSC in combination with UVA1 irradiation inhibited TGF-β1 expression and collagen synthesis in keloid fibroblasts. CONCLUSION: These findings may open up the possibility of clinically used XAS or PSC in combination with UVA1 irradiation for keloid treatments.