Evaluation of the inhibitory potential of essential oils and aromatic extracts on SARS-CoV-2 Mpro and PLpro

Essential oils and aromatic extracts (oleoresins, absolutes, concretes, resinoids) are often used as food flavorings and constituents of fragrance compositions. The flavor and fragrance industry observes significant growth in sales of some natural materials during the COVID-19 outbreak. Some companies worldwide are making false claims regarding their essential oils or blends to be effective (or indirectly points towards this conclusion) against coronaviruses even though the available data on the activity of plant materials against highly pathogenic human coronaviruses is very scarce. Our exploratory study aimed to develop pioneering knowledge, and provide the first experimental results on the inhibitory properties of hundreds of flavor & fragrance materials against SARS-CoV-2 main- and papain-like proteases. As essential oils are volatile products, they could provide an interesting subsidiary inhalation therapeutic strategy in the long term.