Evaluation of semisynthetic chlorophyll-a derivatives as photosensitizers in fibroblast cells

Abstract

In this study, we present the evaluation in fibroblast cells of photosensitizers semi-synthesized derived from chlorophyll a (as described in literature). The process began with the extraction of methyl-pheophorbide a (1), which was then reacted with primary aliphatic amines (butylamine, hexylamine, and octylamine) to yield molecules 2 to 4. Additionally, purpurin-18 methyl ester (5) was obtained through the oxidation of methyl pheophorbide a (1). By adding different aliphatic amines (butylamine, hexylamine, and octylamine) into the anhydride ring of 5, products 6 to 8 were obtained. Compounds 2-4 and 6-8 exhibited absorption bands around 660 nm. The effectiveness of photosensitizers relies on their ability to selectively target damaged cells without harming healthy cells. Therefore, an evaluation of photosensitizers (2-4, 6-8, and chlorin-e6) against HFF-1 fibroblast cells was performed. Testing two different concentrations (1 and 10 µM), it was observed that, under dark conditions, the photosensitizers were primarily non-toxic as they did not significantly reduce cell viability and were close to the control group's viability. Furthermore, the impact of photodynamic therapy (PDT) on cell viability was analyzed by using a light fluence of 30 J/cm 2 . The lower polarity of the compounds (more lipophilic) improved the efficiency of the photosensitizers. In conclusion, this study highlights the successful development of cost-effective photosensitizers with potential applications in PDT. The evaluation against HFF-1 fibroblast cells showed promising results, indicating these photosensitizers could be further investigated for the selective treatment of damaged cells without causing harm to healthy cells.