Study on the synthesis and antimicrobial activity of novel cationic porphyrins

In vitro and in silico evaluation of N-(alkyl/aryl)-2-chloro-4-nitro-5- [(4-nitrophenyl)sulfamoyl]benzamide derivatives for antidiabetic potential using docking and molecular dynamic simulations

A series of N-(alkyl/aryl)-2-chloro-4-nitro-5-[(4-nitrophenyl)sulfamoyl]benzamide derivatives were synthesized and evaluated for its in vitro antidiabetic potential against α-glucosidase and α-amylase enzymes and also for its antimicrobial potential. Compounds N-(2-methyl-4-nitrophenyl)-2-chloro-4-nitro-5-[(4-nitrophenyl)sulfamoyl]benzamide and N-(2-methyl-5-nitrophenyl)-2-chloro-4-nitro-5-[(4-nitrophenyl)sulfamoyl]benzamide were found to be the most potent α-glucosidase and α-amylase inhibitors with IC₅₀ values of 10.13 and 1.52 µM, respectively. The docking results depicted reasonable dock score -10.2 to -8.0 kcal/mol (α-glucosidase), -11.1 to -8.3 kcal/mol (α-amylase) and binding interactions of synthesized molecules with respective targets with enzymes. During molecular dynamic simulations, analysis of RMSD of ligand protein complex suggested stability of the most active compound at binding site of target proteins. Compound N-(2-chloro-4-nitrophenyl)-2-chloro-4-nitro-5-[(4-nitrophenyl)sulfamoyl] benzamide showed antibacterial potential against Gram positive and Gram negative bacteria and compound N-(2-methyl-5-nitrophenyl)-2-chloro-4-nitro-5-[(4-nitrophenyl)sulfamoyl] benzamide showed excellent antifungal potential against Candida albicans and Aspergillus niger. The computational studies were also executed to predict the drug-likeness and ADMET properties of the title compounds. The N-(alkyl/aryl)-2-chloro-4-nitro-5-[(4-nitrophenyl)sulfamoyl]benzamide derivatives showed significant antidiabetic and antimicrobial potential which is equally supported by the molecular dynamic and docking studies. This study will prove useful in revealing the molecular structure and receptor target site details which can be further utilized for the development of newer active antidiabetic and antimicrobial agents.

Investigation of the triplet excited state and application of cationic meso-tetra(cisplatin)porphyrins in antimicrobial photodynamic therapy

In this manuscript, we report, the photophysical study of triplet excited states and antimicrobial photoinactivation of positively charged tetra-cisplatin porphyrin derivatives against Gram + and Gram ‒ bacterial strains. Isomeric cisplatin-porphyrins were used and applied in aPDT assays in the bacilli Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa (Gram negative) and a cocci Staphylococcus aureus (Gram positive) strains. The results show that compound substituted at meta position (3-cis-PtTPyP) is the more efficient photosensitizer against bacteria culture. In this way, tetra-cationic porphyrins containing cisplatin derivatives might be promising aPDT agents with potential applications in clinical infections.

Antibacterial activity of Cu(II) and Co(II) porphyrins: role of ligand modification

In this study, we report antibacterial activity of metalloporphyrins; 5, 10, 15, 20-tetrakis (para-X phenyl)porphyrinato M (II) [where X = H, NH₂ and COOMe for M = Cu and X = COOH  and OMe for M = Co]. The activity study of the as-synthesized metalloporphyrins toward two Gram-positive (S. aureus and S. pyogenes) and two Gram-negative (E. coli and K. pneumoniae) bacteria showed a promising inhibitory activity. Among the complexes under study, the highest antibacterial activity is observed for 5, 10, 15, 20-tetrakis (p-carboxyphenyl)porphyrinato cobalt (II), with inhibition zone of 16.5 mm against Staphylococcus aureus (S. aureus). This activity could be attributed to the high binding ability of COOH group to cellular components, membranes, proteins, and DNA as well as the lipophilicity of the complex. Moreover, consistent with literature report, the study revealed that metalloporphyrins with electron withdrawing group at para-positions have better antibacterial activity than metalloporphyrin which possess electron donating group at para position.

Water-soluble tetra-cationic porphyrins display virucidal activity against Bovine adenovirus and Bovine alphaherpesvirus 1

Porphyrins are photoactive compounds that can absorb the energy of light and transfer it to oxygen molecules, producing reactive oxygen species (ROS). Once produced, ROS may alter biological molecules and cellular mechanisms, leading to cell apoptosis or inactivation of microorganisms, such as bacteria, fungi, and viruses. Therefore, the objective of this study was to evaluate the in vitro virucidal activity of six tetra-cationic porphyrins against two bovine viruses (Bovine alphaherpesvirus 1, BoHV-1, enveloped; and Bovine adenovirus, BAV, non-enveloped). For this, viral suspensions were incubated with each porphyrin (H₂TMeP, ZnTMeP, and CuTMeP at 4.0 μM, NiTMeP at 5.0 μM, and CoClTMeP and MnClTMeP at 1.0 μM) and exposed to white-light irradiation for 0, 60, 120, and 180 min (BAV) or 0, 30, 60, 90, and 120 min (BoHV-1). Then, the remaining viral titers were determined by limiting dilution and compared with the control (virus + porphyrins without light exposition). The porphyrins H₂TMeP and ZnTMeP showed the highest virucidal activity against both viruses. ZnTMeP inactivated BoHV-1 after 30 min of photoactivation and H₂TMeP after 60 min. The BAV was photo-inactivated by both porphyrins at 180 min of white-light exposition. CuTMeP, NiTMeP, and CoClTMeP porphyrins had weak virucidal activity against BoHV-1 and MnClTMeP showed no virucidal activity against both viruses. These results indicated that free-base H₂TMeP and ZnTMeP porphyrins present virucidal activity against non-enveloped and enveloped viruses, opening the possibility for their use to inactivate viruses on surfaces, biological substrates, and solutions.

Photodynamic Inactivation of Candida albicans in Blood Plasma and Whole Blood

The few approved disinfection techniques for blood derivatives promote damage in the blood components, representing risks for the transfusion receptor. Antimicrobial photodynamic therapy (aPDT) seems to be a promising approach for the photoinactivation of pathogens in blood, but only three photosensitizers (PSs) have been approved, methylene blue (MB) for plasma and riboflavin and amotosalen for plasma and platelets. In this study, the efficiency of the porphyrinic photosensitizer Tri-Py(+)-Me and of the porphyrinic formulation FORM was studied in the photoinactivation of Candida albicans in plasma and in whole blood and the results were compared to the ones obtained with the already approved PS MB. The results show that FORM and Tri-Py(+)-Me are promising PSs to inactivate C. albicans in plasma. Although in whole blood the inactivation rates obtained were higher than the ones obtained with MB, further improvements are required. None of these PSs had promoted hemolysis at the isotonic conditions when hemolysis was evaluated in whole blood and after the addition of treated plasma with these PSs to concentrates of red blood cells.

Porphyrinoid photosensitizers mediated photodynamic inactivation against bacteria

The multi-drug resistant bacteria have become a serious problem complicating therapies to such a degree that often the term "post-antibiotic era" is applied to describe the situation. The infections with methicillin-resistant S. aureus, vancomycin-resistant E. faecium, third generation cephalosporin-resistant E. coli, third generation cephalosporin-resistant K. pneumoniae and carbapenem-resistant P. aeruginosa have become commonplace. Thus, the new strategies of infection treatment have been searched for, and one of the approaches is based on photodynamic antimicrobial chemotherapy. Photodynamic protocols require the interaction of photosensitizer, molecular oxygen and light. The aim of this review is to provide a comprehensive overview of photodynamic antimicrobial chemotherapy by porphyrinoid photosensitizers. In the first part of the review information on the mechanism of photodynamic action and the mechanism of the bacteria resistance to the photodynamic technique were described. In the second one, it was described porphyrinoids photosensitizers like: porphyrins, chlorins and phthalocyanines useable in photodynamic bacteria inactivation.

Some activities of PorphyChem illustrated by the applications of porphyrinoids in PDT, PIT and PDI

Photodynamic therapy is an innovative approach to treat diverse cancers and diseases that involves the use of photosensitizing agents along with light of an appropriate wavelength to generate cytotoxic reactive oxygen species.

A Perspective on the Trends and Challenges Facing Porphyrin-Based Anti-Microbial Materials

The emergence of multidrug resistant bacterium threatens to unravel global healthcare systems, built up over centuries of medical research and development. Current antibiotics have little resistance against this onslaught as bacterium strains can quickly evolve effective defense mechanisms. Fortunately, alternative therapies exist and, at the forefront of research lays the photodynamic inhibition approach mediated by porphyrin based photosensitizers. This review will focus on the development of various porphyrins compounds and their incorporation as small molecules, into polymers, fibers and thin films as practical therapeutic agents, utilizing photodynamic therapy to inhibit a wide spectrum of bacterium. The use of photodynamic therapy of these porphyrin molecules are discussed and evaluated according to their electronic and bulk material effect on different bacterium strains. This review also provides an insight into the general direction and challenges facing porphyrins and derivatives as full-fledged therapeutic agents and what needs to be further done in order to be bestowed their rightful and equal status in modern medicine, similar to the very first antibiotic; penicillin itself. It is hoped that, with this perspective, new paradigms and strategies in the application of porphyrins and derivatives will progressively flourish and lead to advances against disease.

Synthesis, characterization and in vitro photodynamic antimicrobial activity of basic amino acid-porphyrin conjugates

Photodynamic antimicrobial chemotherapy (PACT), as a novel and effective modality for the treatment of infection with the advantage of circumventing multidrug resistance, receives great attention in recent years. The photosensitizer is the crucial element in PACT, and cationic porphyrins have been demonstrated to usually be more efficient than neutral and negatively charged analogues towards bacteria in PACT. In this work, three native basic amino acids, l-lysine, l-histidine and l-arginine, were conjugated with amino porphyrins as cationic auxiliary groups, and 13 target compounds were synthesized. This paper reports their syntheses, structural characterizations, oil-water partition coefficients, singlet oxygen generation yields, photo-stability, as well as their photo inactivation efficacies against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Pseudomonas aeruginosa in vitro. The preliminary structure-activity relationship was discussed. Compound 4i, with porphyrin bearing four lysine moieties, displays the highest photo inactivation efficacy against the tested bacterial strains at 3.91 μM with a low light dose (6 J/cm(2)), and it is stable in serum and lower cytotoxicity to A929 cells. These basic amino acid-porphyrin conjugates are potential photosensitizers for PACT.

Comprehensive review in current developments of imidazole-based medicinal chemistry

Imidazole ring is an important five-membered aromatic heterocycle widely present in natural products and synthetic molecules. The unique structural feature of imidazole ring with desirable electron-rich characteristic is beneficial for imidazole derivatives to readily bind with a variety of enzymes and receptors in biological systems through diverse weak interactions, thereby exhibiting broad bioactivities. The related research and developments of imidazole-based medicinal chemistry have become a rapidly developing and increasingly active topic. Particularly, numerous imidazole-based compounds as clinical drugs have been extensively used in the clinic to treat various types of diseases with high therapeutic potency, which have shown the enormous development value. This work systematically gives a comprehensive review in current developments of imidazole-based compounds in the whole range of medicinal chemistry as anticancer, antifungal, antibacterial, antitubercular, anti-inflammatory, antineuropathic, antihypertensive, antihistaminic, antiparasitic, antiobesity, antiviral, and other medicinal agents, together with their potential applications in diagnostics and pathology. It is hoped that this review will be helpful for new thoughts in the quest for rational designs of more active and less toxic imidazole-based medicinal drugs, as well as more effective diagnostic agents and pathologic probes.

Light-activated nanotube-porphyrin conjugates as effective antiviral agents

Porphyrins have been used for photodynamic therapy (PDT) against a wide range of targets like bacteria, viruses and tumor cells. In this work, we report porphyrin-conjugated multi-walled carbon nanotubes (NT-P) as potent antiviral agents. Specifically, we used Protoporphyrin IX (PPIX), which we attached to acid-functionalized multi-walled carbon nanotubes (MWNTs). We decided to use carbon nanotubes as scaffolds because of their ease of recovery from a solution through filtration. In the presence of visible light, NT-P was found to significantly reduce the ability of Influenza A virus to infect mammalian cells. NT-P may be used effectively against influenza viruses with little or no chance of them developing resistance to the treatment. Furthermore, NT-P can be easily recovered through filtration which offers a facile strategy to reuse the active porphyrin moiety to its fullest extent. Thus NT-P conjugates represent a new approach for preparing ex vivo reusable antiviral agents.

5,10,15,20-Tetra-kis(1-methyl-pyridinium-4-yl)porphyrin tetra-iodide tetra-hydrate

The asymmetric unit of the title compound, C₄₄H₃₈N₈²⁺·4I⁻·4H₂O, comprises two halves of non-equivalent cations of 5,10,15,20-tetra­kis­(1-methyl­pyridinium)porphyrin (with the full mol­ecule of each completed by the application of inversion symmetry), four charge balancing iodide anions and four water mol­ecules of crystallization (two water mol­ecules are fully occupied and four mol­ecules have a site occupancy of 50%). The porphyrin cations are arranged into supramolecular columns parallel to the b axis, mediated by π–π [centroid–centroid distance = 3.762 (4) Å] and C—H⋯π supra­molecular inter­actions [C⋯centroid distance = 3.522 (7) Å, C—H⋯centroid = 128°], leading to the formation of columns parallel to the b axis. The close packing leads to the presence of a one-dimensional channel filled with partially occupied water mol­ecules engaged in O—H⋯O and O—H⋯I hydrogen bonds

Antifouling coatings: recent developments in the design of surfaces that prevent fouling by proteins, bacteria, and marine organisms

The major strategies for designing surfaces that prevent fouling due to proteins, bacteria, and marine organisms are reviewed. Biofouling is of great concern in numerous applications ranging from biosensors to biomedical implants and devices, and from food packaging to industrial and marine equipment. The two major approaches to combat surface fouling are based on either preventing biofoulants from attaching or degrading them. One of the key strategies for imparting adhesion resistance involves the functionalization of surfaces with poly(ethylene glycol) (PEG) or oligo(ethylene glycol). Several alternatives to PEG-based coatings have also been designed over the past decade. While protein-resistant coatings may also resist bacterial attachment and subsequent biofilm formation, in order to overcome the fouling-mediated risk of bacterial infection it is highly desirable to design coatings that are bactericidal. Traditional techniques involve the design of coatings that release biocidal agents, including antibiotics, quaternary ammonium salts (QAS), and silver, into the surrounding aqueous environment. However, the emergence of antibiotic- and silver-resistant pathogenic strains has necessitated the development of alternative strategies. Therefore, other techniques based on the use of polycations, enzymes, nanomaterials, and photoactive agents are being investigated. With regard to marine antifouling coatings, restrictions on the use of biocide-releasing coatings have made the generation of nontoxic antifouling surfaces more important. While considerable progress has been made in the design of antifouling coatings, ongoing research in this area should result in the development of even better antifouling materials in the future.

Photoactivated antimicrobial activity of carbon nanotube-porphyrin conjugates

We report the design of antimicrobial nanocomposite films based on conjugates of multiwalled carbon nanotubes (MWNT) and protoporphyrin IX (PPIX) that are highly effective against Staphylococcus aureus (S. aureus) upon irradiation with visible light. S. aureus infections can lead to life-threatening situations, especially when caused by antibiotic-resistant strains. While the light-activated antimicrobial activity of porphyrins against such pathogens is well-known, a facile way to incorporate porphyrins into coatings may lead to their more effective use. To that end, we decided to synthesize and characterize MWNT-PPIX conjugates which combine the biocidal capacity of porphyrins with the mechanical strength of MWNTs. The conjugates could effectively deactivate S. aureus cells in solution upon irradiation with visible light. We also designed large area nanocomposite films comprised of the MWNT-PPIX conjugates that showed potent antimicrobial activity. These MWNT-PPIX conjugates represent a facile strategy for the design of antimicrobial and antifouling coatings.

Benzylidene/2-chlorobenzylidene hydrazides: synthesis, antimicrobial activity, QSAR studies and antiviral evaluation

A series of benzylidene hydrazides (1–20) was synthesized and tested, in vitro, for antibacterial, antifungal and antiviral activities. The microbial screening results indicated that compounds having chloro and nitro substituents were the most active ones. The antiviral evaluation depicted that compounds 9 and 19 were active against Vesicular stomatitis virus (VSV) in HeLa cell cultures. QSAR investigations indicated that the multi-target QSAR model was effective in describing the antimicrobial (antibacterial and antifungal) activity over the one-target QSAR models. Further the mt-QSAR model indicated that the topological parameters, second order molecular connectivity index (²χ) and third order Kier's alpha shape index (κα₃) are effective in describing the antimicrobial activity of synthesized hydrazides.