Brazilian and Mexican propolis and their possible mechanism of action against non-enveloped viruses

Propolis is a resinous substance collected by honeybees and is mostly composed of polyphenols which vary by geographical location. This study investigated the possible mechanism of action of phenolic compounds of Brazilian and Mexican green and red propolis against two non-enveloped viruses. Bacteriophage surrogates, ΦX174 and MS2 were used to assess antiviral properties. Propolis samples were characterized by performing a phenolic profile using ultra-performance liquid chromatography (UPLC), which included 12 phenolic compounds such as phenylpropanoids, flavonoids, phenols, and phenolic. Quercetin, eugenol, kaempferol and naringenin were the most abundant compounds found in propolis. In silico molecular docking was also conducted to determine binding energy and molecular interaction and putative mechanism of propolis phenolic compounds with two viral capsid proteins and two proteins involved in viral replication and infection. The best antiviral effect was in green propolis with a ~ 3,1 and ~ 4.5 log10 reduction in MS2, and ΦX174, respectively. Molecular docking simulations revealed that ΦX174 was also more sensitive to the phenolic compounds and that the combination of quercetin and kaempferol showed the greatest antiviral effect as a possible mechanism, through binding to the viral capsid proteins near the viral genome binding sites.