Antiviral and larvicidal properties of Eucalyptus staigeriana essential oil and its monoterpenes 1,8-cineole and +limonene against Zika virus and Aedes spp

Eucalyptus staigeriana is widely used in several health treatments. Eucalyptus staigeriana essential oil, monoterpenes + Limonene, and 1.8 cineol were evaluated for their antiviral activity against the Zika virus (ZIKV) in vitro and in silico. Larvicidal activity against third-stage larvae of Aedes aegypti and Aedes albopictus was also investigated. The antiviral activity of these compounds was determined at different stages of ZIKV infection and the replication cycle. A molecular docking assay was performed to identify the interaction between 1.8 cineol and ZIKV proteins (NS5 and E proteins) and the interaction between + Limonene and NS1, NS2-NS3, and NS5 non-structural proteins. Only 1.8-cineol showed cytotoxicity at the highest concentration tested in Vero cells, with a CC50 of 958 µg/mL. Although the in silico assay demonstrated a significant interaction between monoterpenes and some viral proteins in vitro, none of the tested substances showed antiviral activity against ZIKV. Of all the substances investigated, only + Limonene exhibited a larvicidal effect on Ae. aegypti larvae (LC50 = 161 μg/mL).