Natural Compounds in Pinus pinaster Needles Essential Oil as an Antibacterial Agent: In Vitro and in Silico Studies

Recently, there has been growing interest in the antimicrobial potential of natural compounds found in essential oils (EOs). In this study, the antibacterial activity of Pinus pinaster essential oil (EO) was assessed against both Gram-negative and Gram-positive bacterial species using the microdilution method in microplates. Additionally, 18 natural compounds from this EO were evaluated through molecular docking for their inhibitory properties on PBP1, PBP2, and PBP3—crucial enzymes in the development of novel antibiotics. The DFT properties, drug-likeness, and ADMET predictions of these compounds were also investigated. The results demonstrated moderate antibacterial activity of P. pinaster EO against all tested bacterial strains, with inhibition zones ranging from 11 to 16 mm. Molecular docking studies indicated that Terpinen-7-al was the most potent compound, binding to the highest number of amino acids within the active sites of the target enzymes, as suggested by the native ligand of each enzyme. Furthermore, the DFT study, along with ADMET and drug-likeness analysis, identified Terpinen-7-al as the most promising compound. Therefore, P. pinaster EO could serve as a significant source of natural molecules with promising antibacterial properties, particularly Terpinen-7-al, which has the potential for development into an antibiotic treatment.