Synthesis of novel pyranoflavylium-based dyes as promising photosensitizers for antimicrobial photodynamic inactivation

• Type: Article in International Scientific Journal
• Date: 2025

Authors

Araújo, P (Author) Other; Correia, P (Author) Other; Mateus, N (Author) Other; Victor de Freitas (Author) FCUP; Iva Fernandes (Author) FCUP; Luis Cruz (Author) FCUP; Joana Oliveira (Author) FCUP

Journal

Title: Dyes and Pigments

Vol. 233

ISSN: 0143-7208

Publisher: Elsevier

Indexing

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Other information

Authenticus ID: P-017-6AG

DOI: 10.1016/j.dyepig.2024.112495

Abstract (EN): Amino-substituted dyes have recently been described for their interesting photosensitizing properties in photodynamic therapy against bacterial growth. In the present study, two novel pyranoflavylium-based dyes namely 4 '-dimethylamino-10-(4''-(dimethylamino)phenyl)pyranoflavylium (4 ',4 '' N(Me)2PyF) and 6-Bromo-4 '- dimethylamino-10-(4''-(dimethylamino)phenyl)pyranoflavylium (6Br4 ',4 '' N(Me)2PyF) were synthesized through the reactions between salicylaldehyde and acetophenone derivatives to improve the photo-properties of 5-hydroxy-4 '-dimethylaminoflavylium (5OH4 ' N(Me)2F), a non-photoactivated flavylium salt previously reported due to the presence of a hydroxyl group in its structure. The presence of a pyranic ring with an additional dimethylaminophenyl group and the insertion of bromine atom changed the spectroscopic properties of the parent flavylium, causing a red shift of the absorption band, higher molar extinction coefficient, and fluorescence emission. Both pyranoflavylium dyes showed appreciable singlet oxygen production, and phototoxicity studies demonstrated their photoactivable nature, leading to a reduction of >3log in cellular viability of S. aureus ATCC 29213 after 15 min of irradiation (22.5 J/cm(2)). In conclusion, this study describes a chemical strategy to extend pi-conjugation, converting a non-active flavylium dye into photoactivable ones. This approach could be further explored to develop novel solutions for antimicrobial photodynamic inactivation, potentially addressing issues related to antimicrobial resistance.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12