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

Abstract

In this study, a family of porphyrins based on 5,10,15,20-Tetrakis(4-ethylphenyl)porphyrin (1, Ph) and six metallo-derivatives (Zn2+(2, Ph-Zn), Sn4+(3, Ph-Sn), Mn2+ (4, Ph-Mn), Ni2+ (5, Ph-Ni), Al3+ (6, Ph-Al), and V3+ (7, Ph-V)) were tested as photosensitizers for photodynamic therapy against Leishmania braziliensis and panamensis. The singlet oxygen quantum yield value (ΦΔ) 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 ΦΔ increased from 0.76–0.90 and cell viability changed considerably. The ΦΔ and metal type changed the cytotoxic activity. Finally, (2) showed both the highest ΦΔ (0.90) and the best photodynamic activity against the parasites studied (IC50 of 1.2 μM).

Photophysical study and in vitro approach against Leishmania panamensis of dicloro-5,10,15,20-tetrakis(4-bromophenyl)porphyrinato Sn(IV)

“…These results concur with previous reports for this compound. 37,38 Compound (2) was prepared by mixing 0.5478 mmol of (1) with 2.2164 mmol SnCl 2 .2H 2 O in DMF (80 mL) for 4 hours at ambient temperature, and by stirring. After that, we added cold water and TBrPP-Sn (IV) precipitated; this solid was washed and dried at ambient temperature.…”

“…These results concur with previous reports for this compound. 37,39 Photophysical properties Fluorescence quantum yield (ϕ f ) was determined by the comparative method in a PTI um 40 fluorimeter. Using as a standard fluorescein dissolved in water, porphyrin (1) and metalloporphyrin (2) was dissolved in ethyl acetate.…”

Photophysical study and in vitro approach against Leishmania panamensis of dicloro-5,10,15,20-tetrakis(4-bromophenyl)porphyrinato Sn(IV)

“…This effect is due to the Sn (IV) ions insertion inside the porphyrin core decreases significantly fluorescence effect. As shown in Table 1, the Φf of (1) was three times greater than (2); the Sn (IV) ions inside the porphyrin core could increase the non-radiative decay of the excited singlet state of porphyrin, 37 Sn (IV) ions within the porphyrin nucleus could increase disintegration by inter-system crossover (ISC), and this pathway is governed by orbital spin coupling at the central atoms; in this case, the insertion of Sn (IV) reduces the fluorescence emission. 9,55,56 A similar effect was reported for cupper insertion inside meso-porphyrinic complexes.…”

“…To perform UV-Vis spectrum (using a UV-2401PC UV-Vis spectrophotometer), we dissolved 2.0×10 −5 g of each compound in ethyl acetate, and finally, we obtained the mass spectrum by dissolving the compound in methanol (using ESI-LC-MS/MS ion Trap amaZon, Bruker spectrometer). Furthermore, we measured fluorescence quantum yield (using a PTI um 40 fluorimeter) and singlet oxygen quantum yield, 37 and electrochemical characterization was performed in four different dissolvents (Dimethylformamide-DMF, dichloromethane -DCM, dimethylsulfoxide-DMSO, tetrahydrofuran-THF) containing 1.0×10 −1 M tetrabutylammonium perchlorate ((C 4 H 9 ) 4 N(ClO 4 ), Aldrich 98% purity) as a supporting electrolyte for all electrochemical measurements.…”

“…The parasite viability was estimated by MTT assay. 37,[43][44][45] Anti-leishmanicidal activity was evaluated at different concentrations (1, 10, 50, 100 and 200 μM) of compound and positive control (Glucantime) under visible-light irradiation, at incubation times of 24, 48 and 72 hours. 37 We used 6 Omnilux LED bulbs located at a close chamber, and an incident photon flow per unit volume I o was 5.7 Â 10 À7 Einstein*L À1 s À1 .…”