Molecular modelling of diterpene compounds from <i>copaifera</i> oleoresin as potential bioactive compounds against SARS‑CoV‑2: calculations of density functional theory and <i>in silico</i> ADME-Tox properties

Trees of the <i>Copaifera</i> genus produce oleoresins in their trunks, known as copaiba oil, widely used for their therapeutic properties. Copaiba oils contain diterpenic acids, rare compounds present in low quantities but with significant potential for treating various diseases. SARS-CoV-2, the causative agent of COVID-19, remains a major public health threat, emphasising the need for antiviral drug development despite vaccine availability. In this study, <i>in silico</i> tests were conducted on diterpenic compounds found in copaiba oil to evaluate their interaction with the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein (SC2Spike). Molecular docking, electrostatic potential maps (MESP), and frontier orbital analysis (HOMO-LUMO) were performed using GaussView and MVD^®. Pharmacokinetic predictions revealed favourable absorption profiles for copaic, cativic, and eperruic acids. Docking identified hardwickic acid as the most promising candidate due to its stable interactions with SC2Spike.