Valorisation of grape pomace for functional antioxidant and antimicrobial agents in chronic wound care

Grape pomace, a by-product of the winemaking industry, is an abundant and underutilized source of polyphenols—bioactive compounds known for their significant health-promoting properties, offering potential applications in food, cosmetics, and pharmaceutical formulations. However, the efficient and environmentally sustainable extraction of these compounds—maximizing yield without compromising their stability or bioactivity—remains a technological challenge. This study presents an innovative extraction approach that integrates sequential enzymatic treatment with microwave-assisted extraction to enhance extraction efficiency and selectivity of polyphenols from grape pomace of Chardonnay and Cabernet Sauvignon varieties cultivated in Romania. The process is followed by purification, detailed compositional characterization of the polyphenolic fraction, and evaluation of antimicrobial activity and biocompatibility. The resulting extracts demonstrated notably high polyphenol yields—1550 ± 12.4 mg per 100 g dry weight (DW) of white Chardonnay grape pomace and 3150 ± 28.4 mg per 100 g dry weight (DW) of Cabernet Sauvignon red grape pomace—alongside strong antioxidant activity. Moreover, the extracts exhibited broad-spectrum antimicrobial effects against both Gram-positive and Gram-negative bacteria, as well as Candida albicans, and showed good biocompatibility with the human keratinocyte (HaCaT) cell line. This optimized extraction method not only enhances yield and preserves bioactive integrity but also positions grape pomace-derived polyphenols as promising candidates for dermatological applications, particularly in the treatment of chronic wounds.