RESUMO

This manuscript presents a new report on the in vitro antimicrobial photo-inactivation of foodborne microorganisms (Salmonella spp. and Listeria monocytogenes) using tetra-cationic porphyrins. Isomeric tetra-cationic porphyrins (3MeTPyP, 4MeTPyP, 3PtTPyP, and 4PtTPyP) were tested, and antimicrobial activity assays were performed at specific photosensitizer concentrations under dark and white-light LED irradiation conditions. Among the tested bacterial strains, 4MeTPyP exhibited the highest efficiency, inhibiting bacterial growth within just 60 min at low concentrations (17.5 µM). The minimal inhibitory concentration of 4MeTPyP increased when reactive oxygen species scavengers were present, indicating the significant involvement of singlet oxygen species in the photooxidation mechanism. Furthermore, the checkerboard assay testing the association of 4MeTPyP showed an indifferent effect. Atomic force microscopy analyses and dynamic simulations were conducted to enhance our understanding of the interaction between this porphyrin and the strain's membrane.

Assuntos

Biofilmes , Listeria monocytogenes , Testes de Sensibilidade Microbiana , Simulação de Dinâmica Molecular , Fármacos Fotossensibilizantes , Porfirinas , Porfirinas/farmacologia , Porfirinas/química , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/química , Biofilmes/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Microbiologia de Alimentos , Antibacterianos/farmacologia , Antibacterianos/química , Microscopia de Força Atômica , Espécies Reativas de Oxigênio/metabolismo , Luz , Oxigênio Singlete/metabolismo , Oxigênio Singlete/química