Abstract: The present invention relates to a mixture M comprising or, alternatively, consisting of: (a) a usnic acid, and/or (b) a relative salt thereof, and/or (c) an inclusion compound (ci), or mixtures thereof, said inclusion compound (ci) comprising or, alternatively, consisting of: (i) said (a) an usnic acid and/or said (b) a relative salt thereof, and (ii) a cyclodextrin, preferably a beta-cyclodextrin, wherein said mixture M is for use in a method for the treatment of viral infections, advantageously said mixture M being capable of inhibiting the spike protein of a coronavirus. Furthermore, the present invention relates to a composition for use in a treatment method according to the present invention, preferably for oral or nasal use, wherein said composition comprises said mixture M and at least one acceptable pharmaceutical or food grade additive and/or excipient.

Abstract: A mixture M of natural origin comprising an usnic acid and/or a salt thereof, preferably an usnic acid sodium salt, in the racemic or dextrorotatory D(+) form and an inclusion compound including (i) a D-usnic acid as an enantiomer, or a salt thereof, or mixtures thereof, of natural origin, and (ii) beta-cyclodextrins and related methods of their use as antibacterial, antibacterial proliferative, bacteriostatic, microbicidal, anti-mould, anti-yeast, antifungal or antimycotic agent, are described.