Effect of Annurca apple polyphenols on human HaCaT keratinocytes proliferation

Polyphenols have been demonstrated to have clear antioxidant activities in vitro. However, in complex biological systems, they exhibit additional properties, which are yet poorly understood. The apple is among the most consumed fruits worldwide, and several studies suggest that apple polyphenols could play a role in the prevention of degenerative diseases. The present study aimed at evaluating the Annurca apple polyphenol extract (APE) effects both proliferation and apoptosis on HaCaT cells. The data indicate that apple polyphenolic compounds had significant antiproliferative action on HaCaT cells. The fluorescence-activated cell-sorting analysis showed that APE induced cell apoptosis in a dose-dependent manner. Moreover, apple polyphenols induced apoptosis in epithelial cells by triggering a death receptor-associated extrinsic pathway p53-independent. APE was also capable of inducing morphological changes as evidenced by nuclear condensation. The cellular, morphological, and molecular data unequivocally demonstrated that induction of cellular apoptosis was mainly responsible for the previously observed antiproliferation-induced APE on HaCaT keratinocytes. Our experimental results suggest that apple polyphenols are a promising source from which a natural-based topical agent could be developed for skin diseases treatment.