The Photo-Protective Activity of Crataegus monogyna Extract Proved by Complementary Mechanisms of Skin Inflammation, Damage of Extracellular Matrix, Cellular Survival and Proliferation Disorders

The skin photo-ageing and photo-carcinogenesis are based on cellular mechanisms triggered by UV-radiation, starting with oxidative stress and inflammation, activation of matrix-metalloproteinase (MMP) that increase the structural protein degradation, ending with DNA damage and apoptosis induction. In order to claim the photo-protective activity of an ingredient it’s important to explore the main pathways involved in this complex process, highlighting its target action. Our studies are based on a cellular screening of UV-A and UV-B irradiated keratinocytes (HaCat cell line), focusing on the apoptosis induction, cell cycle sequentiation, metalloproteinase’s expression, pro-inflammatory cytokines release and IL1α as sensitization molecule, as well as the antioxidant capacity of the extract, and acting on catalase and superoxide-dismutase activity. The investigation techniques are flow cytometry (cellular parameters fluorescent staining and beads-based assay for soluble protein detection), zymography and enzymatic activity tests. The Crataegus monogyna extract, with a rich content of pro-antocians, flavones and polyphenolcarboxylic acids, show a UV-A cellular protection and dose dependent inhibition of inflammatory cytokines and MMP2 and 9 after both UV-A and UV-B irradiation. All these effects are sustained by a cumulative antioxidant capacity at enzymatic and intracellular oxygen radical level. These findings recommend the phyto-complex for the prevention or therapy of UV-photo damages.