Abstract
The identification of natural remedies for the management of the skin aging process is an increasingly growing issue. In this context, ursolic acid (UA), a ubiquitous molecule, mainly contained in Annurca apple (AA) fruit, has demonstrated valuable cosmetic potential. To this end, in the current study, the AA oleolite (AAO, extract in sunflower oil containing 784.40 ± 7.579 µg/mL of UA) was evaluated to inhibit porcine elastase enzymatic reactions through a validated spectrophotometric method. AAO has shown a valuable capacity to contrast the elastase enzyme with a calculated IC(50) of 212.76 mg/mL, in comparison to UA (IC(50) of 135.24 μg/mL) pure molecules and quercetin (IC(50) of 72.47 μg/mL) which are used as positive controls. In this context and in view of the valuable antioxidant potential of AAO, its topical formulation with 2.5% (w/w) AAO was tested in a placebo-controlled, double-blind, two-arm clinical study on 40 volunteers. Our results indicated that after 28 days of treatment, a significant reduction of the nasolabial fold (-7.2 vs. baseline T0, p < 0.001) and forehead wrinkles (-5.3 vs. baseline T0, p < 0.001) were registered in combination with a valuable improvement of the viscoelastic skin parameters, where skin pliability/firmness (R(0)) and gross elasticity (R(2)) were significantly ameliorated (-13% vs. baseline T0, p < 0.001 for R(0) and +12% vs. baseline T0, p < 0.001 for R(2)). Finally, considering the positive correlation between skin elasticity and hydration, the skin moisture was evaluated through the estimation of Trans epidermal water loss (TEWL) and skin conductance.