(-)-Camphene-Based Derivatives as Potential Antibacterial Agents against <i>Staphylococcus Aureus</i> and <i>Enterococcus</i> Spp.
Beatriz Cardoso de Freitas, Paula Assis Queiroz, Vanessa Pietrowski Baldin, Pedro Henrique Rodrigues do Amaral, L. L. Rodrigues, Fábio Vandresen, Katiany Rizzieri Caleffi-Ferracioli, Regiane Bertin de Lima Scodro, Rosilene Fressatti Cardoso, Vera LD Siqueira
Abstract
Aim: To evaluate the activity of (-)-camphene-based thiosemicarbazide (TSC) and 4-hydroxy-thiosemicarbazone (4-OH-TSZ), alone and in combination against Gram-positive. Material & methods: MIC were determined for Staphylococcus aureus, Enterococcus spp. reference strains and clinical isolates. Drug combination, time–kill and cytotoxicity assays were also performed. Results: TSC and 4-OH-TSZ demonstrated potent inhibitory activity against S. aureus and Enterococcus spp., including multidrug-resistant isolates (MIC ranging from 1.9 to 31.2 μg/ml), and were bactericidal for the reference strains of both Gram-positive tested. The derivatives proved to be selective for the bacteria and synergistic with oxacillin and vancomycin. Conclusion: (-)-Camphene-based derivatives can represent promising drug candidates against critical pathogens, such as S. aureus and Enterococcus spp., including MRSA and vancomycin resistance Enterococcus spp. isolates.