Phthalocyanine Derivatives Possessing 2‑(Morpholin-4-yl)ethoxy Groups As Potential Agents for Photodynamic Therapy

Three 2-(morpholin-4-yl)­ethoxy
substituted phthalocyanines were
synthesized and characterized. Phthalocyanine derivatives revealed
moderate to high quantum yields of singlet oxygen production depending
on the solvent applied (e.g., in DMF ranging from 0.25 to 0.53). Their
photosensitizing potential for photodynamic therapy was investigated
in an in vitro model using cancer cell lines. Biological test results
were found particularly encouraging for the zinc­(II) phthalocyanine
derivative possessing two 2-(morpholin-4-yl)­ethoxy substituents in
nonperipheral positions. Cells irradiated for 20 min at 2 mW/cm2 revealed the lowest IC50 value at 0.25 μM
for prostate cell line (PC3), whereas 1.47 μM was observed for
human malignant melanoma (A375) cells. The cytotoxic activity in nonirradiated
cells of novel phthalocyanine was found to be very low. Moreover,
the cellular uptake, localization, cell cycle, apoptosis through an
ELISA assay, and immunochemistry method were investigated in LNCaP
cells. Our results showed that the tested photosensitizer possesses
very interesting biological activity, depending on experimental conditions.