Natural Chlorin e ₆ Derivative Containing a Cationic Dimethyl Piperazinyl Moiety for Efficient Photodynamic Therapy of Cancer

This paper focuses on the behavior of two chlorophyll-type semisynthetic photosensitizers for antitumor photodynamic therapy, which, in our opinion, meet the known criteria associated with efficient photodynamic treatment of superficial malignancies. These natural light-sensitive agents obtained from the <i>Spirulina platensis</i> microalgae are nontoxic pure compounds with low manufacturing costs and good stability in a condensed state and solutions. They have high absorption and emission peaks in the optical window of tissue, have appropriate solubility in water, and generate singlet oxygen with a good quantum yield in both aqueous and lipid-like media. These monocationic chlorin photosensitizers use low- and high-density lipoprotein pathways to accumulate in tumor tissues and penetrate mainly the endoplasmic reticulum and mitochondria of tumor cells. The pilot photodynamic treatment of M1 sarcoma-bearing rats with these macrocycles both as individual light-sensitive agents and, especially, in combination with chlorin e₆ shows their high potential in antitumor photodynamic therapy.