In Vitro Anti-Leishmanial Effect of Metallic Meso-Substituted Porphyrin Derivatives against Leishmania braziliensis and Leishmania panamensis Promastigotes Properties

In this study, a family of porphyrins based on 5,10,15,20-Tetrakis(4-ethylphenyl)porphyrin (1, Ph) and six metallo-derivatives (Zn(2+)(2, Ph-Zn), Sn(4+)(3, Ph-Sn), Mn(2+) (4, Ph-Mn), Ni(2+) (5, Ph-Ni), Al(3+) (6, Ph-Al), and V(3+) (7, Ph-V)) were tested as photosensitizers for photodynamic therapy against Leishmania braziliensis and panamensis. The singlet oxygen quantum yield value (Φ(Δ)) for (1–7) was measured using 1,3-diphenylisobenzofuran (DPBF) as a singlet oxygen trapping agent and 5,10,15,20-(tetraphenyl)-porphyrin (H2TPP) as a reference standard; besides, parasite viability was estimated by the MTT assay. After metal insertion into the porphyrin core, the Φ(Δ) increased from 0.76–0.90 and cell viability changed considerably. The Φ(Δ) and metal type changed the cytotoxic activity. Finally, (2) showed both the highest Φ(Δ) (0.90) and the best photodynamic activity against the parasites studied (IC(50) of 1.2 μM).