EFFECT OF QUERCETIN AND RESVERATROL CO-INCORPORATED IN LIPOSOMES AGAINST INFLAMMATORY/OXIDATIVE RESPONSE ASSOCIATED WITH SKIN CANCER.

The present investigation reports the development of phospholipid vesicles for the coincorporation of quercetin and resveratrol, proposed as a new strategy to treat skin lesions by exploiting the combinatorial effect of the two polyphenols. Quercetin and resveratrol have gained great interest in the pharmaceutical research area due to their wide spectrum of therapeutic activities (i.e., antioxidant, antiradical, anti-inflammatory, anticarcinogenic), coupled with their safety profile (they have GRAS status) and natural origin (they are commonly found in fruits and vegetables). Liposomes were prepared by direct sonication of phosphatidylcholine (Lipoid S75) in buffer, in the presence of quercetin and resveratrol, in combination or as single agents. The physico-chemical properties of the vesicles were assessed by light scattering, ζ-potential, cryogenic transmission electron microscopy and small angle X-ray scattering. The antioxidant power of the two polyphenols, both as raw compounds and formulated in liposomes, was determined by the DPPH assay. The in vitro cytotoxicity and uptake of the polyphenols were tested in human fibroblasts, as well as their activity against ROS, and the in vivo antiinflammatory efficacy was assessed on TPA-treated mouse skin by the determination of oedema formation and myeloperoxidase activity. Light scattering results showed that vesicles were small in size, around 80 nm, with good homogeneity (polydispersity index ≤ 0.25) and highly negative zeta potential values (~-36 mV), due to the charge carried by S75. The liposomes were spherical, uni- and bilamellar structures, with good stability in terms of particle migration and aggregation, as disclosed by the Turbiscan™ technology. Further, both quercetin and resveratrol displayed a potent antioxidant activity, as DPPH radical was almost completely inhibited, even when incorporated in liposomes. The cellular uptake of quercetin and resveratrol was higher when they were formulated in liposomes rather than in solution, and when co-loaded rather than as single agents, which resulted in a superior ability to scavenge ROS. The administration of the polyphenols coloaded in liposomes on TPA-inflamed skin led to a remarkable amelioration of the tissue damage, with a significant reduction of oedema and leukocyte infiltration. Therefore, the proposed approach based on polyphenol vesicular formulations may be of value in the treatment of pre-cancerous/cancerous skin conditions associated with inflammation and oxidative stress