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Photoactivated cell-killing amino-based flavylium compounds
Hélder Oliveira1, Paula Araújo1, Ana Rita Pereira1
1REQUIMTE-Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007, Porto, Portugal.
New nature-inspired flavylium compounds show promise as photosensitizers for photodynamic therapy (PDT). These compounds effectively induce cell damage in skin cells via singlet oxygen and reactive oxygen species production, paving the way for improved PDT treatments.
Area of Science:
- Medicinal Chemistry
- Photochemistry
- Dermatology
Background:
- Photodynamic therapy (PDT) is a recognized treatment modality requiring novel photosensitizers with enhanced photo-features.
- Nature-inspired compounds offer a promising avenue for developing new therapeutic agents.
Purpose of the Study:
- To investigate the potential of five amino-based flavylium compounds as photosensitizers for topical PDT.
- To evaluate the structure-activity relationship of these compounds concerning their photodynamic efficacy.
Main Methods:
- Cytotoxicity assessment of flavylium compounds on fibroblasts and keratinocytes in dark conditions.
- Evaluation of fluorescence quantum yields and singlet oxygen production.
- Photoactivation studies using white light to induce cellular damage and reactive oxygen species (ROS) generation.
Main Results:
- Keratinocytes exhibited higher sensitivity to dark cytotoxicity compared to fibroblasts.
- Specific flavylium compounds demonstrated significant fluorescence and singlet oxygen generation.
- Photoactivated compounds induced potent growth inhibition in keratinocytes at low micromolar concentrations, mediated by ROS and singlet oxygen.
- A structure-activity relationship was established, highlighting the importance of C7-diethylamino and C4'-dimethylamino groups for photoactivation efficiency.
Conclusions:
- Amino-based flavylium compounds are effective photosensitizers for PDT, capable of inducing cell damage through Type I and Type II mechanisms.
- The C7-diethylamino group is crucial for optimal photoactivation efficiency.
- These findings support the development of these flavylium derivatives for advanced topical PDT applications.
