Abstract
Antioxidants are frequently used in sunscreen formulations to complement UV filter photo-protection of synthetic compounds. The current study investigates the application of phenols (recovered from olive mill wastewater) as UV filter in comparison to other natural antioxidants (ascorbic acid and α-tocopherol). The spectrums (220–400 nm) of all assayed antioxidants alone or in combination with synthetic sunscreen agents (Benzophenone-3, Uvinol A, Tinosorb M, TiO2, Octocrylene, OMC and OC-PABA) were obtained and the respective in vitro SPF of the solutions was calculated. Olive phenols were more active UV filters in a broader region of UVB and UVA compared to ascorbic acid and α-tocopherol. However, they were not so active against synthetic compounds especially in the UVB region. The fact that olive phenols absorb in both UV regions of interest allow their application as UV-protection booster in particular cases, e.g. to enhance the absorption of Tinosorb M and Uvinul A solutions in the UVB region and to increase the absorption of Octocrylene, OD-PABA and OMC in the UVA region.
•Phenols from olive mill wastewater and other natural antioxidants were assayed as UV filters.•Spectrums (220–400 nm) of all antioxidants were obtained alone and in combination to synthetic sunscreen agents.•In vitro SPF of respective solutions was calculated.•Olive phenols were more active in a broader region of UVB and UVA.•Potential applications as UV boosters were explored.