RESUMO
Using plant extracts as photosensitizers in photodynamic therapy (PDT) represents a significant green approach toward sustainability. This study investigates beetroot juice (BRJ), betanin, and their liposomal formulations (Lip-BRJ, Lip-Bet) as photosensitizers in cancer PDT. BRJ was prepared, and its betanin content was quantified via HPLC. The p-nitrosodimethylaniline (RNO)/imidazole technique monitored the singlet oxygen formation. BRJ and betanin decreased the RNO absorbance at 440 nm by 12% and 9% after 45 min of irradiation, respectively. Furthermore, betanin interaction with Bcl-2 proteins was examined using binding free energy analysis and molecular dynamic simulation. The results revealed favorable interactions with ΔG values of -40.94 kcal/mol. Then, BRJ, betanin, Lip-BRJ, and Lip-Bet were tested as photosensitizers on normal (HEK 293) and human lung cancer (A549) cell lines. Irradiation significantly enhanced the cytotoxicity of Lip-Bet on HEK 293 cells (20% cell viability at 2000 µg/mL) and A549 cells (13% cell viability at 1000 µg/mL). For Lip-BRJ, irradiation significantly enhanced the cytotoxicity on HEK 293 cells at lower concentrations and on A549 cells at all tested concentrations. These results proved the positive effect of light and liposomal encapsulation on the anticancer activity of betanin and BRJ, suggesting the efficiency of liposomal beetroot pigments as green photosensitizers.
RESUMO
Purpose: Fungal keratitis is a potential corneal contagious disease mainly caused by yeast such as Candida albicans and filamentous fungi such as Aspergillus niger. The response of fungal keratitis to standard antifungals is limited by the poor bioavailability, the limited ocular penetration of antifungal drugs, and the development of microbial resistance. Photodynamic therapy using rose bengal (RB) as a photosensitizer was found to be effective in fungal keratitis management; however, the hydrophilicity of RB limits its corneal penetration. Polypyrrole-coated gold nanoparticles (AuPpy NP) were introduced as a nano-delivery system of RB with high loading capacity. It was proved that (RB-AuPpy NP) exhibited a combined photodynamic/photothermal effect. This study aims to use the combined photodynamic/photothermal effect of RB-AuPpy NP as a novel protocol for treating Fungal Keratitis in albino Wistar rats. Methods: The rats were infected by C. albicans and A. niger. Each infected group of rats was subdivided into groups treated by RB followed by radiation (photodynamic only), AuPpy NP followed by radiation (photothermal only), and RB-AuPpy NP followed by radiation (combined photodynamic/photothermal). Histopathological examination and slit lamp imaging were done to investigate the results. Results: The results revealed that 3 weeks post-treatment, the corneas treated by RB-AuPpy NP (combined photodynamic/photothermal effect) exhibited the best improvement compared to other groups. Conclusion: This protocol can be considered a promising one for Fungal Keratitis management that overcomes microbial resistance problems.