A1. Evaluation of antioxidant activity of lycopene

Abstract

Cutaneous antioxidant capacity can be strengthened by application of suitable substances to the skin. This has been demonstrated for vitamin E, vitamin C, and melatonin, especially when applied in combination. An evaluation was made of the protective capacity of three emulsions containing: (a) lycopene 0.03% (Lycopersicon esculentum extract); (b) alpha-tocopherol acetate (0.5%) and ascorbic acid (1%); (c) a mixture of these three substances at the above concentrations. Twenty healthy volunteers of phototype II or III were irradiated with a solar simulator (Multiport solar UV simulator, model 601) on the flexural surface of the forearm, with doses ranging from 20 to 80 mJ/cm2. The products containing antioxidants were applied on areas with similar characteristics which were irradiated after 30 min with the same UV doses. Skin damage was evaluated measuring erythema and transepidermal water loss before UV exposure and after 24 and 48 h. Erythema was measured by tristimulus colourimeter (Chroma meter CR-200, Minolta) according to our previous experience. The barrier function was evaluated by evaporimeter (Tewameter TM 210, Courage-Khazaka). The product containing lycopene alone had a protective capacity against UV exposure similar to that of the product containing both alpha-tocopherol acetate and ascorbic acid. When the three antioxidants were applied in combination the protective capacity was greater, as demonstrated by statistical evaluation. Lycopene exhibits an antioxidant activity which is enhanced when applied in combination with other substances.