Protective effects of a cream containing Dead Sea minerals against UVB-induced stress in human skin

Background: Dead Sea (DS) mud and water are known for their unique composition of minerals, and for their therapeutic properties on psoriasis and other inflammatory skin diseases. Their mode of action, however, remains poorly known. Objective: To analyse the ability of Dermud™, a leave-on skin preparation containing DS mud and other ingredients like DS water, zinc oxide, aloe-vera extract, pro-vitamin B5 and vitamin E, to antagonize biological effects induced by UVB irradiation in skin when topically applied in organ cultures. Methods: We have used human skin organ cultures as a model to assess the biological effects of UVB irradiation and of Dermud™ cream topical application. Skin pieces were analysed for mitochondrial activity by MTT assay, for apoptosis by caspase 3 assay, for cytokine secretion by solid phase ELISA, for overall antioxidant capacity by ferric reducing antioxidant power and Oxygen radical absorbance capacity assays (epidermis) or by cyclic voltammetry (external medium), and for uric acid (UA) content by HPLC. Results: We report that UVB irradiation decreases cell viability, total antioxidant capacity and UA contents in the epidermis of skin organ cultures, while increasing the levels of apoptosis in cells and their cytokine secretion. Topical application of Dermud™ decreased all these effects significantly. Conclusion: Our results clearly show that Dermud™ has protective, anti-oxidant and anti-inflammatory properties that can antagonize biological effects of UVB irradiation in skin. It may therefore be able to reduce skin photodamage and photoaging, and more generally to reduce oxidative stress and inflammation in skin pathologies.