In vitro photodynamic inactivation of conidia of the phytopathogenic fungus Colletotrichum graminicola with cationic porphyrins.
Photodynamic inactivation (PDI) is an efficient approach for the elimination of a series of microorganisms; however, PDI involving phytopathogenic filamentous fungi is scarce in the literature. In the present study, we have demonstrated the photoinactivating properties of five cationic meso-(1-methyl-4-pyridinio)porphyrins on conidia of the phytopathogen Colletotrichum graminicola. For this purpose, photophysical properties (photostability and (1)O2 singlet production) of the porphyrins under study were first evaluated. PDI assays were then performed with a fluence of 30, 60, 90 and 120 J cm(-2) and varying the porphyrin concentration from 1 to 25 μmol L(-1). Considering the lowest concentration that enabled the best photoinactivation, with the respective lowest effective irradiation time, the meso-(1-methyl-4-pyridinio)porphyrins herein studied could be ranked as follows: triple-charged 4 (1 μmol L(-1) with a fluence of 30 J cm(-2)) > double-charged-trans2 (1 μmol L(-1) with 60 J cm(-2)) > tetra-charged 5 (15 μmol L(-1) with 90 J cm(-2)) > mono-charged 1 (25 μmol L(-1) with 120 J cm(-2)). Double-charged-cis-porphyrin 3 inactivated C. graminicola conidia in the absence of light. Evaluation of the porphyrin binding to the conidia and fluorescence microscopic analysis were also performed, which were in agreement with the PDI results. In conclusion, the cationic porphyrins herein studied were considered efficient photosensitizers to inactivate C. graminicola conidia. The amount and position of positive charges are related to the compounds' amphiphilicity and therefore to their photodynamic activity.
Departamento de Farmácia, Universidade Federal do Paraná, Av. Lothário Meissner, 3400, Jardim Botânico, Curitiba, Paraná, Brazil. sandra.barreira1@gmail.com.
Camila Chevonica
CC
Vandresen
Alan Guilherme
AG
Gonçalves
Diogo Ricardo Bazan
DR
Ducatti
Fabio Seigi
FS
Murakami
Miguel Daniel
MD
Noseda
Maria Eugenia Rabello
ME
Duarte
Sandra Mara Woranovicz
SM
Barreira
D002412:Cations / Q000737:chemistry / Q000494:pharmacology; D020231:Colletotrichum / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D008027:Light; D017319:Photosensitizing Agents / Q000737:chemistry / Q000494:pharmacology*; D010944:Plants / Q000382:microbiology; D011166:Porphyrins / Q000737:chemistry / Q000494:pharmacology*; D026082:Singlet Oxygen / Q000378:metabolism
D002412:Cations; D017319:Photosensitizing Agents; D011166:Porphyrins; D026082:Singlet Oxygen