Antioxidant and Antiviral potential against SARS-CoV-2 of citrus limonoids isolated from Grapefruit Seed Extracts

The COVID-19 pandemic represented an unprecedented global emergency. Despite all efforts, COVID-19 remains a threat to public health, due to the complexity of mass vaccination programs, the lack of effective drugs, and the emergence of new variants. A link has recently been found between the risk of developing a severe COVID-19 infection and a high level of oxidative stress. In this context, we have focused our attention on natural compounds with the aim of finding molecules capable of acting through a dual antiviral / antioxidant mechanisms. In particular, we studied the potential of grapefruit seed extracts (GSE) and their main components, belonging to the class of limonoids. Using several physical and biological approaches including isolation and purification of GSE, oxidative and viability and antiviral assays, we have shown that extracts, particularly extract components belonging to the class of limonoids, are endowed with remarkable virucidal, antioxidant and mitoprotective activity.