P 188 - Antioxidant activity and photoprotective effect of citrus and olive formulations on UVB-induced damage in human keratinocytes

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UV radiation, absorbed by the epidermis, is the major cause of a variety of cutaneous disorders including photoageing and skin cancers. In recent years, an increase in the use of botanicals with antioxidant and anti-inflammatory properties as skin photoprotective agents is emerging. This study evaluated the antioxidant activity and the protective effect of citrus and olive formulations (F1 and F2), against UVB-induced damage in human keratinocytes. F1 contained citrus, rosemary diterpenes and olive polyphenols and F2 citrus and olive flavones. Total phenolic content was determined with Folin-Ciocalteu. The antioxidant activity was evaluated with different methods: trolox equivalent antioxidant capacity (TEAC), ferric reducing-antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Photoprotection study was performed determining the viability of HaCaT cells exposed to UVB through MTT assay. The F1 showed higher phenolic content and antioxidant capacity. Both formulations also exhibited high protective effects on cell survival upon UVB radiation, finding a higher effect for F1 when both were used at same concentration. These results indicate that F1 may be considered as a better ingredient for oral or topical photoprotection. This suggests that, probably not only citrus and olive polyphenols but also rosemary compounds act in the protective action.