Cytotoxicity and Phototoxicity of Chlorophyll a/Hydroxypropyl-γ-cyclodextrin Complex on Leishmania Major Promastigotes

Introduction: Cutaneous leishmaniasis (CL) is a widespread disease that is epidemic in Iran, too. Photodynamic therapy (PDT) is an attractive modality to treat cancer and hyper proliferative diseases based on the use of a photosensitizer in the presence of oxygen and proper wavelength of light. In consideration of lesion location, lack of systemic involvement and inefficiency of current treatments, nowadays this modality is purposed for treating Leishmaniasis. In this paper, efficacy of PDT using a natural dye (chlorophyll a) on Leishmania major promastigotes is reported. Material and Methods: The experiments was done on Leishmania major parasites (MRHO/IR/75/ER) in the presence of Chlorophyll a /Hydroxypropyl-γ-cyclodextrin(chl a/CD) complex as a photosensitizer. At first, dye uptake by promastigotes was evaluated via fluorimetric assessments after different incubation periods. Then dye cytotoxicity was evaluated at different concentration after 24 h incubation. Finally PDT experiments were designed with two doses of light and 10 µM of photosensitizer. Considering all possible controls, the percentage of the parasite survival at 24 hours post treatment was assessed by MTS method. All experiments were repeated at least three times. Results: On the basis of the dye uptake data, 24h was considered for incubating of photosensitizer with promastigotes. IC50 of chl a/CD complex was about 42.6 µM. After parasites irradiation by light at 248 j/cm2, more than 50% of cell death was recorded that is significant in comparing with similar groups without dye, without light, and lower dose of light. In these conditions, ED50 of PDT on promastigotes is determined nearly 246 J/cm2. Discussion and Conclusion: Considering low cytotoxicity in darkness and adequate phototoxicity of chl a/CD complex in comparison with other photosensitizers such as AlPhtalocyanine chloride, it can be introduced as a promising candidate for futher use in PDT experiments on amastigotes and Leishmaniasis animal models.