Porphyrins containing basic aliphatic amino groups as potential broad-spectrum antimicrobial agents

Area of Science:

• Organic Chemistry
• Photochemistry
• Microbiology

Background:

• Porphyrin derivatives are investigated for their photodynamic properties.
• Developing novel photosensitizers is crucial for antimicrobial applications.

Purpose of the Study:

• Synthesize new porphyrin derivatives with basic aliphatic amino groups.
• Evaluate their photodynamic antimicrobial activity against bacteria and yeast.
• Characterize their spectroscopic properties and mechanism of action.

Main Methods:

• Condensation reactions catalyzed by trifluoroacetic acid.
• UV-vis spectroscopy for characterization.
• Photodynamic inactivation assays on Staphylococcus aureus, Escherichia coli, and Candida albicans.
• Singlet oxygen quantum yield determination.

Main Results:

• Three porphyrin derivatives (F10APP, F5APP, TAPP) were synthesized and characterized.
• Porphyrins exhibited red fluorescence and sensitized singlet molecular oxygen production.
• F5APP showed significant photodynamic inactivation of S. aureus (7 log reduction), E. coli, and C. albicans.
• Activity is mainly mediated by singlet oxygen, confirmed by D2O and radical scavenger experiments.

Conclusions:

• The synthesized porphyrins, particularly F5APP, are effective photosensitizers for antimicrobial photodynamic therapy.
• The amphiphilic nature of F5APP enhances its interaction with microbial cell envelopes, boosting photocytotoxic activity.
• These porphyrins represent promising broad-spectrum antimicrobial agents.