Molecular docking analysis of 1,8-cineole with SARS-CoV-2 main protease Mpro and macrodomain MacI : insights into potential weak interactions

Molecular docking is a computational approach that predicts interactions between ligands and protein targets based on binding energies. In this study, the potential interactions of 1,8-cineole -one of the dominant components of Eucalyptus globulus oil- with the main protease (Mpro) and macrodomain (MacI) of SARS-CoV-2 were studied by molecular docking. Nine Mpro and four ManI structures available in the Protein Data Bank (PDB) were assessed as receptors. The results showed binding affinities ranging from −2.1 to −6.3 kcal/mol, primarily mediated by hydrophobic interactions. The most stable complexes were obtained with MacI (PDB: 5RVR, −6.380 kcal/mol) and Mpro (PDB: 5R81, −5.402 kcal/mol). Although the interactions are relatively weak, these results suggest that 1,8-cineole may interact with the SARS-CoV-2 Mpro and MacI, and provide a basis for further experimental studies to validate its effect. Since eucalyptus oil vapor is widely used in the Andean region of Bolivia to prevent respiratory ailments, this work offers an initial in silico rationale for such traditional practices.