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Descrição
The number of antibiotic resistant bacteria is growing faster than the discovery of new drugs, which concerns global health authorities and points to the need of new types of therapies. In this scenario, photodynamic inactivation (PDI) is gaining attention because bacteria are unlikely to develop resistance against it, and because it exhibits a broad-spectrum nature. (1) The PDI effectiveness relies on the action of a photosensitizer (PS) when irradiated in a certain wavelength, once it is close to an adequate molecular target. To be applied in public health, therefore, it requires a careful study in order to determine the means of action of each PS, including molecular targets, providing high selectivity and minimizing toxicity. Although little information is available about it, it is suggested that the cell membrane is a key site for PDI. (2) In this study, Langmuir monolayers made with Escherichia coli total lipid extract were used as a membrane mimetic system to investigate the action of curcumin. This PS is known to be effective against bacteria after photoactivated. (3) Curcumin was found to affect the lipids in the Langmuir monolayer, but in situ blue LED irradiation did not produce significant changes in the film stability or surface potential under the pressure of 30 mN/m. Similar results with negligible influence of LED irradiation were observed for Langmuir monolayers of the synthetic lipids di-octadecyl phosphatidyl ethalonamine (DOPE), palmitoyl-octadecyl phosphoglycerol (POPG) and cardiolipin, which are common in bacteria. Therefore, the molecular targets for curcumin in PDI appear to be other types of molecules. In contrast, light-irradiation effects were observed in curcumin-containing monolayers of di-octadecyl phosphatidyl choline (DOPC), which is frequent in mammal cell membranes. In the latter case, the DOPC monolayer surface potential decreased upon incorporating curcumin, but then increased under blue LED irradiation. These results point to the need of further studies to understand the molecular mechanisms responsible for the action of curcumin.
Referências
1 HAMBLIN, M. R.; ABRAHAMSE, H. Can light-based approaches overcome antimicrobial resistance? Drug Development Research, v. 80, n. 1, p. 48-67, 2019.
2 AWAD, M. M. et al. Important cellular targets for antimicrobial photodynamic therapy. Applied Microbiology and Biotechnology, v. 100, n. 17, p. 7679-7688, 2016.
3 PENHA, C. B. et al. Photodynamic inactivation of foodborne and food spoilage bacteria by curcumin. LWT - Food Science and Technology, v. 76, Part B, p. 198-202, Mar. 2017.
| Apresentação do trabalho acadêmico para o público geral | Não |
|---|---|
| Subárea | Biofísica |
