Millena de Souza Alves 1,*, Maria Alice Araújo de Medeiros 1, Renata Kelly Silva Medeiros 1, Cássio Ilan Soares Medeiros 2, Layane Alves Ramalho 3, Gabrielle Nóbrega Alves 3, Wesley Kauã da Silva Lima 3, Maria Heloísa Furtunato Rocha 4, Luciano de Brito Junior 5 and Abrahão Alves de Oliveira Filho 1
1Federal University of Campina Grande, Department of Postgraduate Studies in Animal Science and Health, Brazil; 2Federal University of Paraíba, Department of Pharmaceutical Sciences, Brazil; 3Federal University of Campina Grande, School of Biological Sciences, Brazil; 4Federal University of Campina Grande, Department of Postgraduate Studies in Forest Sciences; 5Federal University of Campina Grande, Brazil
*Corresponding author: millenaasouzaa@gmail.com
Antimicrobial resistance is one of the major global health challenges. Consequently, the effectiveness of conventional antimicrobials has progressively declined due to the emergence of multidrug-resistant strains, making the search for antimicrobial alternatives essential. This study aimed to evaluate the antimicrobial activity of (R)-(+)-limonene against Pseudomonas aeruginosa strains isolated from food and to investigate its possible mechanism of action via molecular docking with DNA gyrase B. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays were performed using microdilution in 96-well plates, while the Minimum Inhibitory Concentration for Adhesion (MICA) was assessed in test tubes. In addition, interactions with antimicrobials were investigated using the disk diffusion method, and molecular docking was performed with AutoDock 4.2. The results showed an MIC90 of 1000 ?g/mL and an MBC at ratios of 1:1 and 2:1, indicating a bactericidal effect. Regarding anti-adhesive activity, (R)-(+)-limonene inhibited biofilm formation at a dilution ratio of up to 1:8. With regard to combination with antimicrobials, a synergistic effect was observed with ampicillin, gentamicin, tetracycline, ciprofloxacin, ceftazidime, and cefazolin. Additionally, interactions with the active site of the DNA gyrase B enzyme were identified, primarily via hydrophobic, van der Waals, and alkyl/pi-alkyl interactions. These findings reinforce the potential of (R)-(+)-limonene as a promising agent for microbial control and highlight the importance of bioactive compounds derived from essential oils as alternatives or adjuvants for developing new therapeutic strategies in veterinary medicine.