A novel co-monomer based on ellagic acid for free radical polymerization of N-vinyl-2-pyrrolidone acts as potent wound healing agent

Ellagic Acid (EA) is one of the most abundant and relevant antioxidants present in fruits such as berries and pomegranate [1]; on the other hand, its poor solubility both in water and in organic solvents limits its reactivity and its use as food supplements. In the present work we modified the structure of EA and used it as co-monomer for radical polymerization of N-vinyl-2-pyrrolidone (NVP). EA reacted with methacryloyl chloride via a hetero-phase reaction to obtain a single tetra-allyl ester (EAMAC, 80%), highly soluble in organic solvents. Polymers were then obtained via bulk photopolymerization of N-vinyl-2-pyrrolidone with different amounts of EAMAC in a square-shaped PTFE mold. EAMAC acts as radical initiator avoiding the use of photoinitiator and it leads to cross-linked water-compatible polymers. The release of EA from the polymers was assessed both using solutions having different pHs and via enzymatic hydrolytic conditions. The material was tested on HaCaT keratinocytes using a scratch wound assay model. The results demonstrate that: a) antioxidant moieties are protected from degradation during the storage of the polymer; b) the release of EA depends on the kinetic of the hydrolysis of the ester bonds; c) the material significantly increases wound healing.