Broad-spectrum virucidal activity of a hydroalcoholic extract of grape pomace

Grape pomace is a by-product of winemaking often disposed of before full exploitation. Indeed, this natural product holds great potential for sustainable utilization. In this study, dried grape pomace was reprocessed to assess its potential as a valuable source of antiviral metabolites. The antiviral activity of the extract was assessed against Herpes Simplex virus type-2, Feline Calicivirus, Coxsackievirus B5, and Influenza type-A virus, revealing potent broad virucidal effect. Indeed, it abolished viral infection when the extract was incubated with viruses before or during infection, whereas no significant toxic effects were observed up to 3 mg/mL. UHPLC-MS/MS analysis identified quercetin, gallic acid, and ethyl gallate as its primary constituents. These did not fully account for its virucidal action, suggesting the presence of additional active components and/or synergistic effect of more compounds. Thus, grape pomace may be exploited as a sustainable source for the preparation of environmentally friendly broad-spectrum virucidal disinfectants.