Safflower Seed Oil and Fermented Artemisia annua Oil Restore UVB-Induced Skin Barrier Dysfunction by Attenuating Inflammation and Promoting Extracellular Matrix Remodeling

Background: As the body’s first line of defense against environmental stressors, the skin is highly susceptible to UVB-induced damage, which triggers inflammation and impairs barrier function. This study investigates the protective effects of safflower seed oil (SSO) and fermented Artemisia annua oil (FAAO) against UVB-induced skin injury. Methods: The protective effects of SSO and FAO against UVB irradiation was first tested in HaCaT keratinocyte. Subsequently, a UVB-irradiated SKH-1 mouse model was established to evaluate these two oils. RNA-seq analysis was employed to investigate the potential molecular mechanisms by which SSO and FAO repair the skin barrier. Results: In vitro experiments demonstrated that SSO (0.25%) and FAAO (0.1%) significantly enhanced HaCaT keratinocyte viability following UVB exposure while selectively modulating pro-inflammatory cytokine production. In a UVB-irradiated SKH-1 mouse model, standalone SSO or FAAO treatment partially ameliorated epidermal hyperplasia and restored UV-reduced collagen content, while the 1:1 SSO/FAAO combination exhibited superior efficacy in restoring skin architecture, reducing erythema and edema, and suppressing immune cell infiltration. Transcriptomic profiling revealed that the combined treatment promoted structural repair by attenuating inflammatory responses and preserving extracellular matrix homeostasis. Conclusions: Together, these findings underscore the potential of SSO/FAAO as a multifunctional botanical intervention for mitigating UVB-induced cutaneous damage.