A non-invasive method for the in vivo determination of skin antioxidant capacity (IAC-S).

Skin antioxidant network protects cells against oxidative injury and prevents the production of oxidation products. When oxidative stress overwhelms the skin antioxidant capacity, the subsequent modification of the cellular redox apparatus leads to an alteration of cell homeostasis leading to degenerative processes. In the dermocosmetic field, the topical application of antioxidants is often suggested as a possible strategy to prevent and modulate oxidative skin damages. Continuing our studies addressed to set-up new bio-engineering protocols for the claim substantiation of antioxidant cosmetic products, we have developed a new non-invasive methodology for the evaluation of antioxidants cosmetics ingredients and finished products. The effects of a pre-treatment on forearm skin with an antioxidant ingredient were investigated on 15 volunteers, in a double-blind randomised fashion. A non-invasive method was devised that comprises the collection of forehead SC layers of the pre-treated area and control and the next evaluation of skin antioxidant capacity (IAC-S) by a luminescence-based method. The results showed that the antioxidant preparation was able to increase, to a statistically significant extent (P<0.01), the IAC-S in comparison with the control area. The data were confirmed (P<0.05) by comparison with a method, previously developed by us, based on DermAnalyzer. In view of the simplicity and reliability of the method here presented, this new technique is proposed as a possible tool for the routine evaluation of in vivo efficacy of antioxidant functional ingredients and finished products.