Cytoprotective and Genoprotective Effects of Gelatin-Encapsulated Quercetin Against Oxidative Cell Damage

The objective of this study was to compare the protective effects of native and nanostructured quercetin on the initiation of oxidative stress in human keratinocytes exposed to tert-butyl hydroperoxide (tBHP). Quercetin was encapsulated within gelatin-based nanocontainers, forming nanoparticles with diameters ranging from 140 to 180 nm. Two formulations were prepared: uncoated gelatin nanoparticles (NP1) and gelatin nanoparticles coated with a shell composed of dextran sulfate and a chitosan–dextran copolymer (NP2). Cell viability was assessed using PrestoBlue™ reagent. Apoptotic and necrotic cell populations were identified via flow cytometry using an Annexin V-FITC/PI staining kit. DNA damage was evaluated using the comet assay. The results demonstrate that gelatin nanoparticles effectively encapsulate quercetin, and the nanostructured form enables its application in aqueous suspensions without compromising its antioxidant, gene-protective, and cytoprotective effects under conditions of cellular oxidative stress. These findings suggest that gelatin nanoparticles are suitable carriers for quercetin, owing to their high aqueous solubility, which may improve its potential for oral or topical delivery.