Polyphenols Nano-Formulations for Topical Delivery and Skin Tissue Engineering

Skin, the largest human organ, is not sufficiently protected against intrinsic (e.g., physio-pathological oxidative stress) and extrinsic (e.g., radiation and other environmental) injuries. To supplement its own antioxidant arsenal and manage continuous insults, skin care requires multi-disciplinary approaches (e.g., nutraceutics, chemotherapeutics, cosmeceutics, and esthetics). One of them might be the use of polyphenols as natural adjuvant therapeutics. Polyphenols, a superfamily of naturally occurring phytochemicals, are gaining popularity because of their potential skin benefits (i.e., prevention, protection and repair of skin damages). Depending on its structure and physical-chemical features (e.g., bioavailability), the beneficial effects (e.g., enhanced antioxidant, anti-inflammatory, antitumoral, anti-aging properties) exerted by polyphenols in their bulk form may vary. Interestingly, an increasing number of studies suggest that controlled-topical delivery of nano-encapsulated polyphenols (e.g., (−)-epigallocatechin-3-gallate (EGCG), resveratrol) might overcome some limitations frequently observed with topical or systemic bulk polyphenols (e.g., bioavailability, pharmacokinetics, targeting efficacy, toxicity and safety). Therefore, topical application of nano-polyphenols would represent valuable preventive and therapeutic options to provide clinical benefits for individuals with certain skin conditions (e.g., skin inflammation, skin cancers, premature skin aging, skin wound healing). In this chapter, we provide an up-to-date review on available polyphenols in their bulk- and nano-forms that are used for transdermal application and skin engineering (e.g. tissue repair such as wound healing/cicatrization).