Synthesis, Spectroscopy, and Photocytotoxicity of Glycosylated Amino Acid Porphyrin Derivatives as Promising Molecules for Cancer Phototherapy

Maltotriose-Chlorin e6 Conjugate Linked via Tetraethyleneglycol as an Advanced Photosensitizer for Photodynamic Therapy. Synthesis and Antitumor Activities against Canine and Mouse Mammary Carcinoma Cells

Glycoconjugated chlorins represent a promising class of compounds that meet the requirements for the third-generation photosensitizer (PS) for photodynamic therapy (PDT). We have focused on the use of glucose (Glc) to improve the performance of the PS based on the Warburg effect-a phenomenon where tumors consume higher Glc levels than normal cells. However, as a matter of fact, Glc-conjugation has a poor efficacy in hydrophilic modification; thus, the resultant PS is not suitable for intravenous injection. In this study, a Glc-based oligosaccharide, such as maltotriose (Mal₃), is conjugated to chlorin e6 (Ce6). The conjugation is assisted by two additional molecular tools, such as propargyl amine and a tetraethylene glycol (TEG) derivative. This route produced the target Mal₃-Ce6 conjugate linked via the TEG spacer (Mal₃-TEG-Ce6), which shows the required photoabsorption properties in the physiological media. The PDT test using canine mammary carcinoma (SNP) cells suggested that the antitumor activity of Mal₃-TEG-Ce6 is extremely high. Furthermore, in vitro tests against mouse mammary carcinoma (EMT6) cells have been demonstrated, providing insights into the photocytotoxicity, subcellular localization, and analysis of cell death and reactive oxygen species (ROS) generation for the PDT system with Mal₃-TEG-Ce6. Both apoptosis and necrosis of the EMT6 cells occur by ROS that is generated via the photochemical reaction between Mal₃-TEG-Ce6 and molecular oxygen. Consequently, Mal₃-TEG-Ce6 is shown to be a PS showing the currently desired properties.

Photophysical and Bactericidal Properties of Pyridinium and Imidazolium Porphyrins for Photodynamic Antimicrobial Chemotherapy

Despite advances achieved over the last decade, infections caused by multi-drug-resistant bacterial strains are increasingly becoming important societal issues that need to be addressed. New approaches have already been developed in order to overcome this problem. Photodynamic antimicrobial chemotherapy (PACT) could provide an alternative to fight infectious bacteria. Many studies have highlighted the value of cationic photosensitizers in order to improve this approach. This study reports the synthesis and the characterization of cationic porphyrins derived from methylimidazolium and phenylimidazolium porphyrins, along with a comparison of their photophysical properties with the well-known N-methylpyridyl (pyridinium) porphyrin family. PACT tests conducted with the tetracationic porphyrins of these three families showed that these new photosensitizers may offer a good alternative to the classical pyridinium porphyrins, especially against S.aureus and E.coli. In addition, they pave the way to new cationic photosensitizers by the means of derivatization through amide bond formation.

In Silico Study, Synthesis, and Cytotoxic Activities of Porphyrin Derivatives

Five known porphyrins, 5,10,15,20-tetrakis(p-tolyl)porphyrin (TTP), 5,10,15,20-tetrakis(p-bromophenyl)porphyrin (TBrPP), 5,10,15,20-tetrakis(p-aminophenyl)porphyrin (TAPP), 5,10,15-tris(tolyl)-20-mono(p-nitrophenyl)porphyrin (TrTMNP), 5,10,15-tris(tolyl)-20-mono(p-aminophenyl)porphyrin (TrTMAP), and three novel porphyrin derivatives, 5,15-di-[bis(3,4-ethylcarboxymethylenoxy)phenyl]-10,20-di(p-tolyl)porphyrin (DBECPDTP), 5,10-di-[bis(3,4-ethylcarboxymethylenoxy)phenyl]-15,20-di-(methylpyrazole-4-yl)porphyrin (cDBECPDPzP), 5,15-di-[bis(3,4-ethylcarboxymethylenoxy)phenyl]-10,20-di-(methylpyrazole-4-yl)porphyrin (DBECPDPzP), were used to study their interaction with protein targets (in silico study), and were synthesized. Their cytotoxic activities against cancer cell lines were tested using 3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazolium bromide (MTT) assay. The interaction of porphyrin derivatives with carbonic anhydrase IX (CAIX) and REV-ERBβ proteins were studied by molecular docking and molecular dynamic simulation. In silico study results reveal that DBECPDPzP and TrTMNP showed the highest binding interaction with REV- ERBβ and CAIX, respectively, and both complexes of DBECPDPzP-REV-ERBβ and TrTMNP-CAIX showed good and comparable stability during molecular dynamic simulation. The studied porphyrins have selective growth inhibition activities against tested cancer cells and are categorized as marginally active compounds based on their IC₅₀.

meso-Mono-[4-(1,4,7-triazacyclononanyl)]-tri(phenyl)]porphyrin and the respective zinc(ii)-complex: complete characterization and biomolecules binding abilities

We aimed to synthesize a new series of triazacyclononanyl-porphyrins (4and5) with the potential ability to bind DNA.

Asymmetric zinc phthalocyanines substituted with a single carboxyl and triethyleneoxysulfonyl groups: synthesis, characterization and validation for photodynamic therapy

This work describes modular pathway towards the synthesis of new specific unsymmetrically (AB3) zinc phthalocyanines that contains three polyoxy ethylene and monocarboxylic acid groups as photosensitizers. Their photophysical and photochemical properties are studied. General trends are described for quantum yields of fluorescence, photodegradation and singlet oxygen quantum yields of these compounds. Therefore, these novel phthalocyanines could potentially be good photosensitizers for photodynamic therapy.

Synthesis of three novel imidazolyl-appended porphyrins and their cytostatic and phototoxic activity on A431 cells

Three imidazolyl-appended porphyrins were synthesized and characterized by 1 H NMR, elemental analyses, MS and UV-vis spectra. Anticancer activities of porphyrins have been evaluated against cutaneous squamous cell carcinoma (A431 cells) in vitro. The results indicate that the porphyrins have high selective cytotoxicity towards A431 cells in the absence of light and improved phototoxic activity upon exposure to UV light. The yield of singlet oxygen generated by porphyrins were also evaluated by measuring the absorption decay of 1,3-diphenylisobenzofuran (DPBF) in DMF. The phototoxicities of porphyrins against A431 cells were enhanced along with the increase of singlet oxygen.

Synthesis of meso-substituted dihydro-1,3-oxazinoporphyrins

Novel dihydro-1,3-oxazinoporphyrins and naphtho[e]bis(dihydro-1,3-oxazinoporphyrin) derivatives, in which the porphyrin macrocycle is covalently linked to the dihydro-1,3-oxazine ring system were successfully synthesized from 5-(4-aminophenyl)-10,15,20-triphenylporphyrin in good yields. The structures of the target products were established on the basis of spectral data and elemental analyses.

Synthesis and photodynamic properties of maltohexaose-conjugated porphyrins

A series of porphyrin derivatives with one to four maltohexaose moieties in their meso positions have been synthesized. Zinc or free-base m-THPP (5,10,15,20-tetrakis(m-hydroxyphenyl)-porphyrin) was used as the porphyrin platform. The reaction of m-THPP with 3-iodopropyl nonadecaacetylmaltohexaoside afforded a mixture of all possible combinations of glycoconjugated porphyrins having one to four maltohexaose moieties; monoglycosylated (Ac-1), bisglycosylated (Ac-cis-2 and Ac-trans-2), triglycosylated (Ac-3), and tetraglycosylated (Ac-4) porphyrins were obtained in 11–26% yield. Removal of acetyl groups at maltohexaose moiety afforded highly water-soluble glycoconjugated porphyrins 1–4. Zinc derivatives were synthesized in a similar manner. These maltohexaose-linked porphyrins exhibit remarkable water-solublity (530 mg/mL for 4). The singlet oxygen production ability upon visible light irradiation is not affected by the maltohexaose substitution. Photo- and dark cytotoxicities of the maltohexaose-conjugated porphyrins 1–4 and Zn-1–4 were examined against a HeLa cell line, which showed that the mono-maltohexaosylated derivative (1 and Zn-1) was the most effective photosensitizer for PDT.

Synthesis and photodynamic activity of new imidazole substituted pyropheophorbide-a derivatives

Two new imidazole substituted chlorin derivatives, namely (4-[1-imidazolyl]-phenyl)-amide pyropheophorbide-a and (3-[1-imidazolyl]-propyl)-amide pyropheophorbide-a have been synthesized. Their cell viabilities on A549 human lung adenocarcinoma cells were investigated and compared with that of pyropheophorbide-a. According to the phototoxicity study, (4-[1-imidazolyl]-phenyl)-amide pyropheophorbide-a and (3-[1-imidazolyl]-propyl)-amide pyropheophorbide-a were found superior to pyropheophorbide-a with respect to high phototoxicity. This work demonstrates that imidazole substituted chlorin derivatives could be a promising candidate for photodynamic therapy and are worth further investigations.

Selectivity among two lectins: probing the effect of topology, multivalency and flexibility of "clicked" multivalent glycoclusters

The design of multivalent glycoconjugates has been developed over the past decades to obtain high-affinity ligands for lectin receptors. While multivalency frequently increases the affinity of a ligand for its lectin through the so-called "glycoside cluster effect", the binding profiles towards different lectins have been much less investigated. We have designed a series of multivalent galactosylated glycoconjugates and studied their binding properties towards two lectins, from plant and bacterial origins, to determine their potential selectivity. The synthesis was achieved through copper(I)-catalysed azide-alkyne cycloaddition (CuAAC) under microwave activation between propargylated multivalent scaffolds and an azido-functionalised carbohydrate derivative. The interactions of two galactose-binding lectins from Pseudomonas aeruginosa (PA-IL) and Erythrina cristagalli (ECA) with the synthesized glycoclusters were studied by hemagglutination inhibition assays (HIA), surface plasmon resonance (SPR) and isothermal titration microcalorimetry (ITC). The results obtained illustrate the influence of the scaffold's geometry on the affinity towards the lectin and also on the relative potency in comparison with a monovalent galactoside reference probe.

Synthesis, structure, electrochemistry and spectral characterization of (D-glucopyranose)-4-phenylthiosemicarbazide metal complexes and their antitumor activity against Ehrlich ascites carcinoma in Swiss albino mice

The novel glycosyl saccharide derivative, (D-glucopyranose)-4-phenylthiosemicarbazide (LH) and its complexes, with cobalt(II), nickel(II), copper(II) and zinc(II) were synthesized, characterised and tested for cytotoxic effects. The copper complex, [CuLCl] inhibited Ehrlich Ascites Carcinoma (EAC) induced cancer cell lines in Swiss albino mice at LC50=1.94 x 10(-8) (LC50=2.76 x 10(-8) for cisplatin) and so distinctly better than free ligand and other complexes.

Conjugation of 2-(1'-hexyloxyethyl)-2-devinylpyropheophorbide-a (HPPH) to carbohydrates changes its subcellular distribution and enhances photodynamic activity in vivo

The carbohydrate moieties on conjugating with 3-(1'-hexyloxyethyl)-3-devinyl pyropeophorbide-a (HPPH) altered the uptake and intracellular localization from mitochondria to lysosomes. In vitro, HPPH-Gal 9 PDT showed increased PDT efficacy over HPPH-PDT as detectable by the oxidative cross-linking of nonphosphorylated STAT3 and cell killing in ABCG2-expressing RIF cells but not in ABCG2-negative Colon26 cells. This increased efficacy in RIF cells could at least partially be attributed to increased cellular accumulation of 9, suggesting a role of the ABCG2 transporter for which HPPH is a substrate. While such differences in the accumulation in HPPH derivatives by tumor tissue in vivo were not detectable, 9 still showed an elevated light dose-dependent activity compared to HPPH in mice bearing RIF as well as Colon26 tumors. Further optimization of the carbohydrate conjugates at variable treatment parameters in vivo is currently underway.

Glycosyl bis-porphyrin conjugates: Synthesis and potential application in PDT

Syntheses of new glycosylated neutral and cationic porphyrin dimers linked at the meso-position via a flexible hydrocarbon chain are described. A detailed 1H and 13C NMR study allows their complete structural elucidation. The UV-visible, fluorescence and MALDI mass spectra are also presented. Photocytotoxicities of these compounds against K562 leukaemia cell line are compared to those of Photofrin II.

Pharmacokinetics of a tri-glucoconjugated 5,10,15-(meta)-trihydroxyphenyl-20-phenyl porphyrin photosensitizer for PDT. A single dose study in the rat

Photodynamic therapy (PDT) involves a non invasive treatment of small and superficial cancers using a photosensitive drug and light to kill tumoral cells. 5,10,15-meso-tri-(meta-O-beta-D-glucosyloxyphenyl)-20-phenylporphyrin [m-TPP(glu)3] is a new photosensitizer (PS) with more enhanced photocytotoxicity relative to 5,10,15,20-meso-tetra-(meta-hydroxyphenyl) chlorin [m-THPC] (Foscan). It was injected intravenously once to healthy rats at three different doses (0.25, 0.5 and 1 mg kg(-1)) and compared to m-THPC (0.3 mg kg(-1)). Pharmacokinetic parameters for both photosensitizers were derived from plasma concentration-time data using a non-compartmental analysis and a two-compartment pharmacokinetic model. m-TPP(glu)3 is more rapidly eliminated throughout the organism than m-THPC. Its mean plasma clearance is 19 mL h(-1) kg(-1) (6 mL h(-1) kg(-1) for m-THPC), and its mean residence time is 5h (20 h for m-THPC). The area under curve (AUC) and initial mean serum concentration (C0) were found to be proportional to the dose. As for Foscan, no metabolite of m-TPP(glu)3 was detected in plasma. The biodistribution study demonstrates that the most significant amount of m-TPP(glu)3 was concentrated in organs such as lung, liver and spleen which are rich in reticulo-endothelial cells. Maximum concentrations were reached in organs 14 h after IV administration. At 48 h, the photosensitizer was essentially eliminated from all organs. Because of its shorter elimination time, m-TPP(glu)3 is more attractive than m-THPC as a PDT agent since secondary side effects of shorter duration could be expected.

Polyamine conjugates of meso-tritolylporphyrin and protoporphyrin IX: Potential agents for photodynamic therapy of cancers

An efficient five-step synthesis method was developed to obtain tritolylporphyrin and protoporphyrin IX polyamine conjugates. These compounds were composed of either one polyamine unit (spermidine or spermine) covalently tethered to monocarboxyphenyl tritolylporphyrin or two molecules of polyamines borne by protoporphyrin IX. In each compound, an aliphatic spacer arm is linked to the N(4) polyamine position. Photocytotoxicity of these new compounds was evaluated against K562 human chronic myelogenous leukemia cells and compared to Photofrin II; protoporphyrin IX polyamine conjugates exhibited much stronger photocytocicity than Photofrin II and were shown to readily induce necrosis in treated cells.

Synthesis of glycoporphyrin derivatives and their antiviral activity against herpes simplex virus types 1 and 2

Studies on the synthesis, structural elucidation, and antiviral evaluation of several carbohydrate-substituted meso-tetraarylporphyrins against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are described. The potential of those photosensitizers, and of their precursors, on the photoinactivation of HSV-1 and HSV-2 was examined in Vero cells. Their virucidal and viral replication effects were assessed under white light, at their maximum noncytotoxic concentrations. The highest inhibitory effects on viral replication, for both viruses, were obtained with the glycoporphyrins where the sugar moiety bears unprotected hydroxyl groups. Strong inhibition of virus yield was observed even at concentrations much lower than their maximum noncytotoxic concentrations. These compounds can be postulated to be useful as potential drugs for the treatment of herpes simplex viruses infections.

Amino porphyrins as photoinhibitors of Gram-positive and -negative bacteria

Twenty four aminoporphyrin derivatives have been tested in vitro for their antibacterial photoactivity against Escherichia coli and Staphylococcus aureus. Two of these compounds, bearing polyamine units, exhibited a significant activity especially against Gram-negative bacteria (E. coli).

Microwave-assisted glycosylation for the synthesis of glycopeptides

An efficient one-step synthesis of O-linked glycosylamino acids is described. This methodology converts commercially available peracetylated mono- and disaccharides activated by cheap and environmentally safe FeCl(3) under microwave irradiation with Fmoc-Ser-OBn to the corresponding beta-glycosides in short reaction times and moderate yields.

Novel Carbohydrate-Appended Metal Complexes for Potential Use in Molecular Imaging

Seven discrete sugar-pendant diamines were complexed to the {M(CO)(3)}(+) ((99m)Tc/Re) core: 1,3-diamino-2-propyl beta-D-glucopyranoside (L(1)), 1,3-diamino-2-propyl beta-D-xylopyranoside (L(2)), 1,3-diamino-2-propyl alpha-D-mannopyranoside (L(3)), 1,3-diamino-2-propyl alpha-D-galactopyranoside (L(4)), 1,3-diamino-2-propyl beta-D-galactopyranoside (L(5)), 1,3-diamino-2-propyl beta-(alpha-D-glucopyranosyl-(1,4)-D-glucopyranoside) (L(6)), and bis(aminomethyl)bis[(beta-D-glucopyranosyloxy)methyl]methane (L(7)). The Re complexes [Re(L(1)-L(7))(Br)(CO)(3)] were characterized by (1)H and (13)C 1D/2D NMR spectroscopy which confirmed the pendant nature of the carbohydrate moieties in solution. Additional characterization was provided by IR spectroscopy, elemental analysis, and mass spectrometry. Two analogues, [Re(L(2))(CO)(3)Br] and [Re(L(3))(CO)(3)Br], were characterized in the solid state by X-ray crystallography and represent the first reported structures of Re organometallic carbohydrate compounds. Conductivity measurements in H(2)O established that the complexes exist as [Re(L(1)-L(7))(H(2)O)(CO)(3)]Br in aqueous conditions. Radiolabelling of L(1)-L(7) with [(99m)Tc(H(2)O)(3)(CO)(3)](+) afforded in high yield compounds of identical character to the Re analogues. The radiolabelled compounds were determined to exhibit high in vitro stability towards ligand exchange in the presence of an excess of either cysteine or histidine over a 24 h period.

In Vitro Demonstration of the Heavy-Atom Effect for Photodynamic Therapy

Photodynamic therapy (PDT) is an emerging treatment modality for a range of disease classes, both cancerous and noncancerous. This has brought about an active pursuit of new PDT agents that can be optimized for the unique set of photophysical characteristics that are required for a successful clinical agent. We now describe a totally new class of PDT agent, the BF2-chelated 3,5-diaryl-1H-pyrrol-2-yl-3,5-diarylpyrrol-2-ylideneamines (tetraarylazadipyrromethenes). Optimized synthetic procedures have been developed to facilitate the generation of an array of specifically substituted derivatives to demonstrate how control of key therapeutic parameters such as wavelength of maximum absorbance and singlet-oxygen generation can be achieved. Photosensitizer absorption maxima can be varied within the body's therapeutic window between 650 and 700 nm, with high extinction coefficients ranging from 75,000 to 85,000 M(-1) cm(-1). Photosensitizer singlet-oxygen generation level was modulated by the exploitation of the heavy-atom effect. An array of photosensitizers with and without bromine atom substituents gave rise to a series of compounds with varying singlet-oxygen generation profiles. X-ray structural evidence indicates that the substitution of the bromine atoms has not caused a planarity distortion of the photosensitizer. Comparative singlet-oxygen production levels of each photosensitizer versus two standards demonstrated a modulating effect on singlet-oxygen generation depending upon substituent patterns about the photosensitizer. Confocal laser scanning microscopy imaging of 18a in HeLa cervical carcinoma cells proved that the photosensitizer was exclusively localized to the cellular cytoplasm. In vitro light-induced toxicity assays in HeLa cervical carcinoma and MRC5-SV40 transformed fibroblast cancer cell lines confirmed that the heavy-atom effect is viable in a live cellular system and that it can be exploited to modulate assay efficacy. Direct comparison of the efficacy of the photosensitizers 18b and 19b, which only differ in molecular structure by the presence of two bromine atoms, illustrated an increase in efficacy of more than a 1000-fold in both cell lines. All photosensitizers have very low to nondeterminable dark toxicity in our assay system.

Chloroalkyl piperazine and nitrogen mustard porphyrins: synthesis and anticancer activity

Fifteen new chloroalkyl piperazine and nitrogen mustard porphyrins have been synthesized by the direct condensation of chloroalkyl piperazine, nitrogen mustard benzaldehyde, and pyrrole. Each porphyrin bears 1-4 chloroalkyl piperazine or nitrogen mustard moieties, which have been used as drugs. The Lindsey method was modified to synthesize chloroalkyl piperazine and nitrogen mustard porphyrins. To successfully synthesize chloroalkyl piperazine and nitrogen mustard porphyrins, catalyst acidity was proved to be the key factor, while the ratio of pyrrole to aldehyde had great influence on product yield. The synthetic chloroalkyl piperazine and nitrogen mustard porphyrins were characterized by elementary analysis, MS, (1)H NMR, IR, and UV-vis. Their anticancer activity to bel-7404 liver cancer cells was tested by the MTT assay. Most of the synthetic porphyrins had good anticancer activity toward bel-7404 liver cancer cells in the absence of light. These compounds might be potential anticancer medicines.

Speciation of new tri- and tetra-glucoconjugated tetrapyrrolic macrocycles (porphyrins and chlorins): an electronic molecular spectroscopy study

In this work, we study the physicochemical properties of some newly developed glycoconjugated photosensitizers that can be used in photodynamic therapy (PDT) of cancers: meso-tri- and tetra-(meta-O-beta-D-glucosyloxyphenyl)porphyrins and meso-, tri-, and tetra-(meta-O-beta-D-glucosyloxyphenyl)chlorins. Their properties are compared to the non-glycosylated hydroxylated parent compounds meso-tetra-(meta-hydroxyphenyl) porphyrin and meso-tetra-(meta-hydroxyphenyl)chlorin. It was found that at the ground state, all porphyrins present, independent of the substitution, have the same mean ionization constant (pKa = 2.7), corresponding to two indistiguishable steps of protonation of tetrapyrrolic nitrogens. On the other hand, in the case of chlorins, one proton process can be observed and the corresponding nitrogen exhibits a slightly superior basicity (pKa = 3.0) with respect to porphyrins. Hydroxylated compounds present a second transition at high pH corresponding to the ionization of phenol groups (pKa = 10.5). Consequently, all photosensitizers are not charged at physiological pH (approximately 7.4), and so the ionization process does not influence their activity in biological media. Ionization induces very important variations in photosensitizer absorption and emission spectra. For example, absorption in the red region (band V), one of the most important characteristics of a good photosensitizer, is only important for diprotonated porphyrins and neutral chlorins. As far as fluorescence emission is concerned, neutral chlorins are almost six times more fluorescent than the corresponding neutral porphyrins (phi(chlorin)/phi(porphyrin) approximately = 6). It should be emphasized that the spectra modifications induced by pH variations can find interesting applications in the optimization of visible and fluorescence detection in high-performance liquid chromatography (HPLC) as well as in the development of direct, rapid fluorimetric analytical methods.

Self-assembling of the porphyrin-linked acyclic penta- and heptapeptides in aqueous trifluoroethanol

The conjugates of porphyrin with links to the acyclic penta- and heptapeptides were synthesized to mimic natural multiple porphyrin systems. The linear penta- and heptapeptide with hydrophilic/hydrophobic alternative sequences took a random structure in aqueous trifluoroethanol (TFE). However, these polypeptides took a beta-sheet structure in the same solvent when the N-terminal Cys linked to the porphyrin, suggesting that the conjugates self-assembled via the intermolecular hydrophobic interaction between the porphyrins. The circular dichroism (CD) spectra, UV/vis spectra, size exclusion chromatography (SEC), and (1)H NMR spectroscopy supported the self-assembling. In the self-assembled structure of the pentapeptide linking porphyrin at the p-phenyl position (9), the porphyrins were involved in two porphyrin-porphyrin interactions, i.e., the side-by-side interaction between the neighboring polypeptide chains and the face-to-face interaction between the first and the third peptide chains. The CD spectra of 9 showed two sets of Cotton effects probably arising from these two interactions. The UV/vis spectra also supported the above interpretation, showing multiple absorptions in the longwave and shortwave shifted regions. The SEC analyses showed the assembled structure of the conjugates. The (1)H NMR signals of the porphyrin rings of 9 were hardly observed in D(2)O-CD(3)OD because of the shortened spin-spin relaxation time T(2)().

Study on synthesis, characterization and biological activity of some new nitrogen heterocycle porphyrins

Seven new nitrogen heterocycle porphyrins, 5,10,15,20-tetra[4-(N-pyrrolidinyl)phenyl]porphine (TBPPH(2)), 5,10,15,20-tetra[4-(4'-ethylpiperazinyl)phenyl]porphine (TEPPH(2)), 5,10,15,20-tetra [4-(4'-butylpiperazinyl)phenyl]porphine (TUPPH(2)), 5,10,15,20-tetra[4-(4'-heptylpiperazinyl) phenyl]porphine (THPPH(2)), 5-[4-(4'-ethylpiperazinyl)phenyl]-10,15,20-triphenylporphine (MEPPH(2)), 5-[4-(4'-buthylpiperazinyl)phenyl]-10,15,20-triphenylporphine (MUPPH(2)) and piperazine bridge porphine dimer N,N'-di(5,10,15,20-tetraphenylporphinato)piperazine (DiPPH(2)) have been synthesized by the direct condensation of nitrogen heterocycle substituted benzaldehydes with pyrrole. Each porphine bears one or four substituted pyrrolidine or piperazine moieties that have been used as drugs. Their structures were characterized by elementary analysis, MS, 1H NMR, IR and UV-vis. These nitrogen heterocycle porphyrins aggregates in water and THF solution were studied by the spectrophotofluorimetry. The anticancer activity of these porphines for the liver cancer cells, the stomach tumor cells and the nasopharyngeal carcinoma cancer cells were tested by the MTT assay. Compared with cis-platinum (cis-Pt) and 5-Fluorouracil (5-Fu), the nitrogen heterocycle porphyrins have the better biological activity and might have potential application in medicine.

Synthesis, cellular internalization and photodynamic activity of glucoconjugated derivatives of tri and tetra(meta-hydroxyphenyl)chlorins

Glucoconjugated tri and tetra(meta-hydroxyphenyl)chlorins have been synthesized in order to explore how glucoconjugation of the macrocycle affects the photoactivity of the molecule. Internalization processes, photosensitizing efficacy of TPC(m-O-GluOH)(3) and TPC(m-O-GluOH)(4), in HT29 human adenocarcinoma cells have been compared to those of tetra(meta-hydroxyphenyl) chlorin (m-THPC, Foscan). The tetra glucoconjugated chlorin, TPC(m-O-GluOH)(4), was found to be poorly internalized and weakly photoactive. In contrast, the asymmetric and more amphiphilic compound TPC(m-O-GluOH)(3), exhibited superior phototoxicity compared to m-THPC. Drug concentration, temperature and sodium azide effects indicated that TPC(m-O-GluOH)(3) internalization partly proceeds via an active receptor-mediated endocytosis mechanism. Cellular uptake appeared as a saturable process and remained 30% lower than for mTHPC. However, a maximum phototoxicity in HT29 cells (survival fraction of 2+/-0.6%) were observed for concentration as low as 2 microM. A 4-fold higher concentration of m-THPC was necessary to observe the same level of photoactivity. This higher phototoxicity has been correlated to a greater mitochondrial affinity. On the basis of these results, work is in progress to further evaluate the potential of glycosylated chlorins in photodynamic therapy (PDT).

Synthesis and biological evaluation of thioglycosylated porphyrins for an application in photodynamic therapy

The aim of this work is the synthesis of a new family of glycosylated porphyrins in which the sugar moieties are linked to the tetrapyrrole ring by a thioglycosidic bond. Two series have been designed. The first one corresponds to meso-aryl porphyrin derivatives. The second one has been obtained from protoporphyrin IX derivatization. Aryl-porphyrins were prepared from tristolyl o- and p-hydroxyporphyrins followed by bromoallylation and thioglycosylation with peracetylated S-glucose, mannose and galactose and deprotection. The other series has been synthesized from protoporphyrin IX dimethylester with a regioselective glycosylation of terminal alkenyl carbon. The UV-visible, NMR and MALDI mass spectra are presented. Photocytotoxicities of the synthesized compounds against K562 chronic leukaemia cell line has been evaluated.

Unprecedented sugar-dependent in vivo antitumor activity of carbohydrate-pendant cis-diamminedichloroplatinum(II) complexes

Eight carbohydrate-pendant platinum(II) complexes have been synthesized from carbohydrate-diamine conjugates. D-Glucose, D-mannose, D-galactose, D-xylose, and L-glucose are attached to the dichloroplatinum(II) moiety by 1,3- or 1,2-diaminopropane chelates through with an O-glycoside bond. All the carbohydrate moieties reduced the toxicity inherent with platinum(II) complexes.

Synthesis and biological evaluation of methoxyphenyl porphyrin derivatives as potential photodynamic agents

A new meso-2,4,6-trimethoxyphenyl porphyrin covalently linked to a 2',6'-dinitro-4'-trifluoromethylphenyl group by an amine bond 5 and its metal complex with Cd(II) 6 was prepared. The photodynamic activities of 5 and 6 were evaluated in vitro on Hep-2 cells. A considerable increase in the photocytotoxic effect was found for 6, which has higher singlet molecular oxygen, O(2)((1)Delta(g)), production.

Photodynamic studies of metallo 5,10,15,20-tetrakis(4-methoxyphenyl) porphyrin: photochemical characterization and biological consequences in a human carcinoma cell line

The photodynamic activities of the free-base 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin (TMP) and their metal complexes with zinc(II) (ZnTMP), copper(II) (CuTMP) and cadmium(II) (CdTMP) have been compared in two systems: reverse micelle of n-heptane/sodium bis(2-ethylhexyl)sulfosuccinate/water bearing photooxidizable substrates and Hep-2 human larynx carcinoma cell line. The quantum yields of singlet molecular oxygen, O2(1 delta g), production (phi delta) of TMP, ZnTMP and CdTMP in tetrahydrofuran, were determined yielding values of 0.65, 0.73 and 0.73, respectively, while O2(1 delta g) formation was not detected for CuTMP. In the reverse micellar system, the amino acid L-tryptophan (Trp) was used as biological substrate to analyze the O2(1 delta g)-mediated photooxidation. The observed rate constants for Trp photooxidation (kobsTrp) were proportional to the sensitizer quantum yield of O2(1 delta g). A value of approximately 2 x 10(7) s-1 M-1 was found for the second-order rate constant of Trp (krTry) in this system. The response of Hep-2 cells to cytotoxicity photoinduced by these agents in a biological medium was studied. The Hep-2 cultures were treated with 1 microM of porphyrin for 24 h at 37 degrees C and the cells exposed to visible light. The cell survival at different light exposure levels was dependent on phi delta. Under these conditions, the cytotoxic effect increases in the order: Cu-TMP << TMP < ZnTMP approximately CdTMP, correlating with the production of O2(1 delta g). A similar behavior was observed in both the chemical and biological media indicating that the O2(1 delta g) mediation appears to be mainly responsible for the cell inactivation.

Photodynamic activity of 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin on the Hep-2 human carcinoma cell line: effect of light dose and wavelength range

The photodynamic activity of 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin (TMP) has been investigated in two systems: reverse micelles of n-heptane/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/water-bearing photooxidizable substrates and on a Hep-2 human carcinoma cell line. The effect of variation in the light dose and wavelength range (360-800, 455-800, and 590-800 nm) was compared in both media. The aerobic singlet oxygen-mediated photooxidation of L-tryptophan (Trp) was used as a model of biological substrate in a micellar system. A considerable increase of the observed rate constants of Trp (k(Trp)(obs)) was noted, increasing the irradiated area of the TMP spectrum. In vitro, the survival curves of Hep-2 cells, treated with TMP, were markedly dependent on the light wavelength ranges used for irradiation. A linear behavior between k(Trp)(obs) and the photoinactivation rate of Hep-2 cells was found, indicating that the singlet oxygen (1O2 ) is the main species responsible for cell inactivation. These results contributed to an understanding of the photodynamic process yielded by this porphyrin in vitro and the sensitivity of Hep-2 cells to photodamage.