Antioxidant Activity of Citrus Limonoids and Investigation of Their Virucidal Potential against SARS-CoV-2 in Cellular Models.

Fabio Magurano,Domenico Nuzzo,Antonella Marchi,Paola Bucci,Giorgia Catinella,Andrea Pinto,Matteo Micucci,Marzia Sucameli,Gigliola Borgonovo,Pasquale Picone,Sabrina Dallavalle,Melissa Baggieri,Silvia Gioacchini

doi:10.3390/antiox10111794

Abstract

The COVID-19 pandemic represents 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 virucidal–antioxidant mechanism. In particular, we studied the potential of grapefruit seed extracts (GSE) and their main components, belonging to the class of limonoids. Using chemical and biological approaches including isolation and purification of GSE, antioxidant and virucidal assays, we have shown that grapefruit seed constituents, belonging to the class of limonoids, are endowed with remarkable virucidal, antioxidant and mitoprotective activity.

Highlights

Coronaviruses (CoVs) are large, positive-stranded, enveloped RNA viruses that generally cause enteric and respiratory diseases in humans and in animals
Intrigued by the possibility of having a safe and accessible natural extract in the arsenal of weapons against SARS-CoV-2, in the present work we aimed to evaluate the ability of extracts of grapefruit seeds to directly counteract SARS-CoV-2 infection using a two-pronged approach, which involves both virucidal and antioxidant activities
We investigated the natural extract of grapefruit seeds as a source of active molecules to fight against SARS-CoV-2 infection by a dual approach, involving both virucidal and antioxidant activity

Summary

Introduction

Coronaviruses (CoVs) are large, positive-stranded, enveloped RNA viruses that generally cause enteric and respiratory diseases in humans and in animals. CoVs have recently attracted global attention to their lethal potential and great infectious capacity. A highly pathogenic CoV, called SARS-CoV-2, dramatically emerged in December. 2019 in Wuhan, China and has rapidly spread around the world during the COVID-19. SARS-CoV-2 infection and the destruction of lung cells triggers a local immune response, recruiting macrophages and monocytes to respond to the infection. The increased release of cytokines produces an excessive amount of reactive oxygen species (ROS) in various tissues. Viral infections are often associated with acute oxidative stress, influencing the pathogenesis of diseases as well as the inflammatory

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