The photodynamic activities of novel asymmetrically meso-substituted cationic porphyrins, 5,10-di(4-methylphenyl)-15,20-di(4-trimethylammoniumphenyl)porphyrin iodide 1 and 5-(4-trifluorophenyl)-10,15,20-tris(4-trimethylammoniumphenyl)porphyrin iodide 2 and its metal complex with Pd(II) 3, have been investigated in both homogeneous medium bearing photooxidizable substrates and in vitro on a typical gram-negative bacterium Escherichia coli. The amphiphilic character of porphyrin 2 was increased by the presence of a high-lipophilic trifluoromethyl group and its photophysical properties changed by forming a complex with Pd(II). Absorption and fluorescence spectroscopic studies were compared in different media. Fluorescence quantum yields (phi(F)) of 0.16 for 1 in tetrahydrofuran and 0.08 for 2 in N, N-dimethylformamide (DMF) were calculated, whereas no significant emission was detected for Pd(II) porphyrin 3. The singlet molecular oxygen, O(2)((1)Delta(g)), production was evaluated using 9,10-dimethylanthracene in DMF yielding relative values of 1, 0.55 and 0.47 for porphyrins 3, 2 and 1, respectively. A faster decomposition of l-tryptophan was obtained using Pd(II) porphyrin 3 as sensitizer with respect to the free-base porphyrins 1 and 2. In biological medium, the behavior of cationic porphyrins 1-3 were compared with that of 5-(4-carboxyphenyl)-10,15,20-tris(4-methylphenyl)porphyrin 4, which was used as a noncationic sensitizer. These porphyrins are rapidly bound to E. coli cells in 5 min and the amount of cell-bound sensitizer is not appreciably changed incubating the cultures for longer times. The recovered porphyrin 2 after one washing step reaches a value of approximately 2.9 nmol/10(6) cells and this amount remains high even after three washes, indicating that this sensitizer is tightly bound to cells. Photosensitized inactivation of E. coli was analyzed using cells without and with one washing step. In both cases, a higher photoinactivation of cells was found for tricationic porphyrin 2 and 3, causing a approximately 5.5 log (99.999%) decrease of cell survival, when treated with 10 microM of sensitizer. Under these conditions, a lower effect was found for porphyrin 1 (approximately 4 log) whereas sensitizer 4 did not produce appreciable photodamage. The results were also confirmed by growth delay experiments. These studies show that the amphiphilic tricationic porphyrin 2 and 3 bearing a trifluoromethyl group can be a promising model for phototherapeutic agents with potential applications in inactivation of bacteria by photodynamic therapy.
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 photodynamic activities of novel asymmetrically meso-substituted cationic porphyrins, 5,10-di(4-methylphenyl)-15,20-di(4-trimethylammoniumphenyl)porphyrin iodide 1 and 5-(4-trifluorophenyl)-10,15,20-tris(4-trimethylammoniumphenyl)porphyrin iodide 2 and its metal complex with Pd(II) 3, have been investigated in both homogeneous medium bearing photooxidizable substrates and in vitro on a typical gram-negative bacterium Escherichia coli. The amphiphilic character of porphyrin 2 was increased by the presence of a high-lipophilic trifluoromethyl group and its photophysical properties changed by forming a complex with Pd(II). Absorption and fluorescence spectroscopic studies were compared in different media. Fluorescence quantum yields (phi(F)) of 0.16 for 1 in tetrahydrofuran and 0.08 for 2 in N, N-dimethylformamide (DMF) were calculated, whereas no significant emission was detected for Pd(II) porphyrin 3. The singlet molecular oxygen, O(2)((1)Delta(g)), production was evaluated using 9,10-dimethylanthracene in DMF yielding relative values of 1, 0.55 and 0.47 for porphyrins 3, 2 and 1, respectively. A faster decomposition of l-tryptophan was obtained using Pd(II) porphyrin 3 as sensitizer with respect to the free-base porphyrins 1 and 2. In biological medium, the behavior of cationic porphyrins 1-3 were compared with that of 5-(4-carboxyphenyl)-10,15,20-tris(4-methylphenyl)porphyrin 4, which was used as a noncationic sensitizer. These porphyrins are rapidly bound to E. coli cells in 5 min and the amount of cell-bound sensitizer is not appreciably changed incubating the cultures for longer times. The recovered porphyrin 2 after one washing step reaches a value of approximately 2.9 nmol/10(6) cells and this amount remains high even after three washes, indicating that this sensitizer is tightly bound to cells. Photosensitized inactivation of E. coli was analyzed using cells without and with one washing step. In both cases, a higher photoinactivation of cells was found for tricationic porphyrin 2 and 3, causing a approximately 5.5 log (99.999%) decrease of cell survival, when treated with 10 microM of sensitizer. Under these conditions, a lower effect was found for porphyrin 1 (approximately 4 log) whereas sensitizer 4 did not produce appreciable photodamage. The results were also confirmed by growth delay experiments. These studies show that the amphiphilic tricationic porphyrin 2 and 3 bearing a trifluoromethyl group can be a promising model for phototherapeutic agents with potential applications in inactivation of bacteria by photodynamic therapy.
Novel meso-substituted cationic porphyrins have been synthesized as potential photodynamic agents. 5,10-bis(4-Acetamidophenyl)-15,20-bis(4-methylphenyl)porphyrin 1 was prepared using a modification of the Alder-Longo procedure. However, two different approaches were compared in the synthesis of 5-(4-trifluorophenyl)-10,15,20-tris(4-acetamidophenyl)porphyrin 2. One involved a condensation of binary mixture of aldehydes and pyrrole under equilibrium conditions and the other a binary mixture of aldehydes and meso-(4-acetamidophenyl)dipyrromethane 3. The last synthetic pathway was advantageous mainly for an easier reaction work up and a higher yield. Both amido porphyrin 1 and 2 were hydrolyzed in basic media and treated with methyl iodide to form 5,10-di(4-methylphenyl)-15,20-di(4-trimethylammonium phenyl)porphyrin iodide 4 and 5-(4-trifluorophenyl)-10,15,20-tris(4-trimethyl ammoniumphenyl)porphyrin iodide 5, respectively. Porphyrin 5 bears a highly lipophilic trifluoromethyl group, which increases the amphiphilic character of the structure. On the other hand, the photodynamic properties of porphyrin 5 were changed forming metal complex with Pd(II), porphyrin 6. Absorption and fluorescence spectroscopic studies of these porphyrins were compared in different solvents. These amphiphilic cationic porphyrins are promising photosensitizers with potential applications in bacteria inactivation by photodynamic therapy.
The photodynamic activities of novel asymmetrically meso substituted cationic porphyrins, 5,10‐di(4‐methylphenyl)‐ 15,20‐di(4‐trimethylammoniumphenyl)porphyrin iodide 1 and 5‐(4‐trifluorophenyl)‐10,15,20‐tris(4‐trimethylammoniumphenyl)porphyrin iodide 2 and its metal complex with Pd(II) 3, have been investigated in both homogeneous medium bearing photooxidizable substrates and in vitro on a typical gram‐negative bacterium Escherichia coli. The amphiphilic character of porphyrin 2 was increased by the presence of a high‐lipophilic trifluoromethyl group and its photophysical properties changed by forming a complex with Pd(II). Absorption and fluorescence spectroscopic studies were compared in different media. Fluorescence quantum yields (øF) of 0.16 for 1 in tetrahydrofuran and 0.08 for 2 in N, N‐dimethylformamide (DMF) were calculated, whereas no significant emission was detected for Pd(II) porphyrin 3. The singlet molecular oxygen, O2(1Δ(g), production was evaluated using 9,10‐dimethylanthracene in DMF yielding relative values of 1, 0.55 and 0.47 for porphyrins 3, 2 and 1, respectively. A faster decomposition of L‐tryptophan was obtained using Pd(II) porphyrin 3 as sensitizer with respect to the free‐base porphyrins 1 and 2. In biological medium, the behavior of cationic porphyrins 1‐3 were compared with that of 5‐(4‐carboxyphenyl)‐10,15,20‐tris(4‐methylphenyl)porphyrin 4, which was used as a noncationic sensitizer. These porphyrins are rapidly bound to E. coli cells in 5 min and the amount of cell‐bound sensitizer is not appreciably changed incubating the cultures for longer times. The recovered porphyrin 2 after one washing step reaches a value of ∼2.9 nmol/106 cells and this amount remains high even after three washes, indicating that this sensitizer is tightly bound to cells. Photosensitized inactivation of E. coli was analyzed using cells without and with one washing step. In both cases, a higher photoinactivation of cells was found for tricationic porphyrin 2 and 3, causing a ‐5.5 log (99.999%) decrease of cell survival, when treated with 10 μM of sensitizer. Under these conditions, a lower effect was found for porphyrin 1 (‐4 log) whereas sensitizer 4 did not produce appreciable photodamage. The results were also confirmed by growth delay experiments. These studies show that the amphiphilic tricationic porphyrin 2 and 3 bearing a trifluoromethyl group can be a promising model for phototherapeutic agents with potential applications in inactivation of bacteria by photodynamic therapy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.