Effects of combined treatment with Curcuma longa extract, curcumin, or bisdemethoxycurcumin and UVA on imiquimod-induced psoriasis-like lesions in BALB/c mice

The combination of Curcuma longa extract and its active compounds, curcumin and bisdemethoxycurcumin, as photosensitizers with ultraviolet A (UVA) light has potential in alleviating psoriasis. This study evaluated their therapeutic effects on psoriasis-like lesions induced via imiquimod application in BALB/c mice. Treatments with Curcuma longa extract, curcumin, or bisdemethoxycurcumin combined with UVA (TUVA, CUVA, and BUVA, respectively) were administered. All treatments improved abnormal transepidermal water loss and subcutaneous hydration in the dorsal skin. TUVA and CUVA significantly reduced ear thickness and epithelial thickness in both the ear and dorsal skin. All treatments restored the expression of filaggrin, loricrin, and keratin 1, while downregulating interleukin-1 β, tumor necrosis factor-α, interferon-γ, and IL-23p19. These findings suggest that Curcuma longa extract, curcumin, or bisdemethoxycurcumin combined with UVA treatment may serve as potential alternatives to conventional antipsoriatic therapies such as psoralen plus ultraviolet A therapy.