Evaluation of the anti-SARS-CoV-2 properties of essential oils and aromatic extracts

Abstract

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 observed significant growth in the sales of some natural materials during the COVID-19 outbreak. Some companies worldwide are making false claims regarding the effectiveness of their essential oils or blends (or indirectly point toward this conclusion) against coronaviruses, even though the available data on the activity of plant materials against highly pathogenic human coronaviruses are very scarce. Our exploratory study aimed to develop pioneering knowledge and provide the first experimental results on the inhibitory properties of hundreds of flavor and fragrance materials against SARS-CoV-2 main and papain-like proteases and the antiviral potential of the most active protease inhibitors. As essential oils are volatile products, they could provide an interesting therapeutic strategy for subsidiary inhalation in the long term.

Figure 1

The interactions of dimethyl anthranilate in the active centers of SARS-CoV-2 M^pro (A) and SARS-CoV-2 PL^pro (B). The binding for each enzyme is shown for the S1-S1′ and S2-S1 pockets. The surface of the enzymes is colored light blue (M^pro) or light pink (PL^pro). The surface of methyl N-methylanthranilate is colored dark brown for the S1-S1′ pockets and green for the S2-S1 pockets. The ligands and the side chains of the amino acids are shown as sticks, and the bond order is not shown.

Figure 2

The interactions of benzyl benzoate (A), benzyl cinnamate (B), cinnamyl cinnamate (C), and cinnamic acid (D) in the active center of SARS-CoV-2 M^pro. The ligands and the side chains of the amino acids are shown as sticks, and the bond order is not shown.