Grape Skin Extract–Enriched Hydrogels for Wound Healing: An Antioxidant- Based Approach

Abstract

Gelatin–alginate hydrogels incorporating grape skin extract (GSE) from the Šumadija region were prepared by blending alginate and gelatin (3:1, 3:2, 1:1), casting, freezing, and CaCl₂ cross-linking. Organoleptic properties, total phenolic content (TPC, Folin–Ciocalteu), and antioxidant activity (DPPH and ABTS microplate assays with Trolox) were evaluated. GSE-loaded hydrogels formed uniform, solid gels. Compared with blank matrices, GSE increased TPC by approximately 46–79% and produced modest but consistent reductions in SC50 values: 0.3–1.8% in ABTS and 0.5–1.6% in DPPH (Trolox 6.909 and 5.034 μg/mL, respectively). Across GSE formulations, higher gelatin fractions correlated with higher TPC and lower ABTS SC50, suggesting protein–polyphenol interactions that enhance aqueous availability, whereas DPPH responses were minimally affected. These findings indicate that GSE incorporation preserves antioxidant functionality and yields small in-assay gains, with composition exerting a stronger effect in ABTS than in DPPH. The platform is a sustainable route to bioactive wound dressings and merits further optimization and biological validation.