Photodynamic activity of cationic and non-charged Zn(ii) tetrapyridinoporphyrazine derivatives: biological consequences in human erythrocytes and Escherichia coli

Abstract

The photodynamic activity of a cationic Zn(II) tetramethyltetrapyridinoporphyrazinium salt (ZnPc ) was compared with that of a non-charged Zn(II) tetrapyridinoporphyrazine (ZnPc 1), both in vitro using human red blood (HRB) cells and a typical Gram-negative bacterium Escherichia coli. Absorption and fluorescence spectroscopic studies were analyzed in different media. Fluorescence quantum yields (phi(F)) of 0.35 for ZnPc 1 and 0.30 for ZnPc 2 were calculated in N,N-dimethylformamide (DMF). The singlet molecular oxygen, O(2)((1)Delta(g)), production was evaluated using 9,10-dimethylanthracene (DMA) in DMF yielding values of Phi(Delta)= 0.56 for ZnPc 1 and 0.50 for ZnPc 2. In biological medium, the photodynamic effect was first evaluated in HRB cells. Both phthalocyanines produce similar photohemolysis of HRB cells, reaching values >90% of lysis after 5 min of irradiation with visible light. The photodynamic effect is accompanied by an increase in the membrane fluidity of HRB cells. However, these studies on E. coli cells showed that the cationic ZnPc 2 produces a higher photoinactivation of Gram-negative bacteria than ZnPc 1. Also, these results were established by stopped of growth curves for E. coli. Therefore the studies show that cationic ZnPc 2 is an efficient phototherapeutic agent with potential applications in tumor cell and Gram-negative bacteria inactivation by photodynamic therapy.

The in vitro PDT efficacy of a novel metallophthalocyanine (MPc) derivative and established 5‐ALA photosensitizing dyes against human metastatic melanoma cells

“…Despite the successful destruction of some forms of skin cancer with 5-ALA PDT treatment, the attempt to manage cutaneous MM with PDT has not yet been successful [14,21]. Studies recently performed though, suggest that possibly the use of metalloid-activated phthalocyanine PSs may aid in the destruction of MM [22], since they are activated at even higher and longer wavelengths, perhaps giving them the ability to penetrate through MM lesions and the melanin they contain ultimately destroying them [12,17]. But based on the present experience, PDT in its current form is not acceptable as an alternative treatment modality for MM and the photodynamic reaction requires further investigation [3].…”

Synthesis and photodynamic properties of amphiphilic A3B-phthalocyanine derivatives bearing N-heterocycles as potential cationic phototherapeutic agents

“…The structure of ZnPc 1 was the precursor of an unsymmetrical A 3 B monocationic phthalonitrile, while ZnPc 2 and 3 were used to produce dicationic phthalocyanines by methylation of annulated 6-membered N-heterocycles [15]. Thus, cationic phthalocyanines 4e6 were obtained by treating the corresponding ZnPc 1e3 with dimethyl sulphate for 18 h at 120 C (Scheme 2).…”

“…An aliquot (100 mL) of aqueous and organic phases were dissolved in 2 mL of N,N-dimethylformamide (DMF) and the final phthalocyanine concentration determined by absorption spectroscopy [15].…”

“…Both phthalocyanines produce similar photohemolysis of HRB cells. However, only the cationic phthalocyanine induces significant photoinactivation of Gram-negative bacteria [15].…”

Photosensitization Ability of a Water Soluble Zinc(II)tetramethyltetrapyridinoporphyrazinium Salt in Aqueous Solution and Biomimetic Reverse Micelles Medium

“…12,13 This phthalocyanine is aggregated in several solvents, including micellar systems with low water content. However, partial monomerization takes place increasing the amount of water dispersed in n-heptane/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/water micellar system, but extensive aggregation was found in pure water.…”