Antifungal activity of silver and zinc complexes of sulfadrug derivatives incorporating arylsulfonylureido moieties

Ligation Motifs in Zinc-Bound Sulfonamide Drugs Assayed by IR Ion Spectroscopy

The sulfonamide–zinc ion interaction, performing a key role in various biological contexts, is the focus of the present study, with the aim of elucidating ligation motifs in zinc complexes of sulfa drugs, namely sulfadiazine (SDZ) and sulfathiazole (STZ), in a perturbation-free environment. To this end, an approach is exploited based on mass spectrometry coupled with infrared multiple photon dissociation (IRMPD) spectroscopy backed by quantum chemical calculations. IR spectra of Zn(H2O+SDZ−H)+ and Zn(H2O+STZ−H)+ ions are consistent with a three-coordinate zinc complex, where ZnOH+ binds to the uncharged sulfonamide via N(heterocycle) and O(sulfonyl) donor atoms. Alternative prototropic isomers Zn(OH2)(SDZ−H)+ and Zn(OH2)(STZ−H)+ lie 63 and 26 kJ mol−1 higher in free energy, respectively, relative to the ground state Zn(OH)(SDZ)+ and Zn(OH)(STZ)+ species and do not contribute to any significant extent in the sampled population.

Biocompatibility and Effectiveness of a Novel, Organic Olive Oil-Based Denture Adhesive: A Multicenter Randomized and Placebo-Controlled Clinical Trial

To assess the clinical efficacy of a novel, organic olive oil-based denture adhesive and its effect on Candida albicans growth in maxillary edentulous individuals wearing complete dentures, individuals were selected from two dental schools in Portugal and Spain. Twenty-eight complete dentures were relined, following a standardized protocol. The novel product (test) was compared with a commercialized adhesive (control) and Vaseline (placebo) randomly assigned in a cross-study design. The retention resistance was measured with a gnathometer and a dynamometer. The patients related outcome evaluations with a five-point questionnaire, and the Candida albicans growth in a Sabouraud dextrose agar (SDA) medium was used to evaluate differences between the placebo and experimental product. Twenty-three participants were included. The dynamometer evaluation showed significant differences between not using a denture adhesive and using either (experimental, p = 0.03; control, p = 0.04) and no significant differences between the two adhesives (p > 0.05). In the subjective analysis, the experimental adhesive showed a significantly longer effectiveness (p = 0.001), and the control reported better results in taste (p = 0.03) and in chewing (p = 0.001). The test adhesive showed better (p < 0.001) Candida albicans growth inhibition. The experimental adhesive showed longer effectiveness than the control and the placebo with a better inhibition capacity for the growth of Candida albicans. Patients reported better abilities for speech, chewing, taste, and retirement in the control adhesive.

Antimicrobial and antitumor activity of S-methyl dithiocarbazate Schiff base zinc(II) complexes

Schiff bases (SB) obtained from S-methyl dithiocarbazate and aromatic aldehydes: salicylaldehyde (H₂L¹), o-vanillin (H₂L²), pyridoxal (H₂L³) and 2,6-diformyl-4-methylphenol (H₃L⁴), and their corresponding Zn(II)-complexes (1-4), are synthesized. All compounds are characterized by elemental analyses, infrared, UV-Vis, nuclear magnetic resonance spectroscopy and mass spectrometry. The structures of H₂L² and [Zn₂(L¹)₂(H₂O)(DMF)] (1a) (DMF = dimethylformamide) are solved by single crystal X-ray diffraction. The SB coordinates the metal center through the O_phenolate, N_imine and S_thiolate atoms. The radical scavenging activity is tested using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, with all ligand precursors showing IC₅₀ values ~40 μM. Cytotoxicity studies with several tumor cell lines (PC-3, MCF-7 and Caco-2) as well as a non-tumoral cell line (NHDF) are reported. Interestingly, 1 has relevant and selective antiproliferative effect against Caco-2 cells (IC₅₀ = 9.1 μM). Their antimicrobial activity is evaluated in five bacterial strains (Klebsiella pneumoniae, Acinetobacter baumannii, Listeria monocytogenes, Pseudomonas aeruginosa and Staphylococcus aureus) and two yeast strains (Candida albicans and Candida tropicalis) with some compounds showing bacteriostatic and fungicidal activity. The minimal inhibitory concentration (MIC₉₀) of H_nL against Mycobacterium tuberculosis is also reported, with H₂L² and H₃L⁴ showing very high activity (MIC₉₀ < 0.6 μg/mL). The ability of the compounds to bind bovine serum albumin (BSA) and DNA is evaluated for H₃L⁴ and [Zn₂(L⁴)(CH₃COO)] (4), both showing high binding constants to BSA (ca. 10⁶ M^-1) and ability to bind DNA. Overall, the reported compounds show relevant antitumor and antimicrobial properties, our data indicating they may be promising compounds in several fields of medicinal chemistry.

High Bactericidal Self-Assembled Nano-Monolayer of Silver Sulfadiazine on Hydroxylated Material Surfaces

Anti-infective surfaces are a modern strategy to address the issue of infection related to the clinical use of materials for implants and medical devices. Nanocoatings, with their high surface/mass ratio, lend themselves to being mono-layered on the material surfaces to release antibacterial molecules and prevent bacterial adhesion. Here, a “layer-by-layer” (LbL) approach to achieve a self-assembled monolayer (SAM) with high microbicidal effect on hydroxylated surfaces is presented, exploiting the reaction between a monolayer of thiolic functions on glass/quartz surfaces and a newly synthesized derivative of the well-known antibacterial compound silver sulfadiazine. Using several different techniques, it is demonstrated that a nano-monolayer of silver sulfadiazine is formed on the surfaces. The surface-functionalized materials showed efficient bactericidal effect against both Gram-positive and Gram-negative bacteria. Interestingly, bactericidal self-assembled nano-monolayers of silver sulfadiazine could be achieved on a large variety of materials by simply pre-depositing glass-like SiO₂ films on their surfaces.

Quinolone-fused cyclic sulfonamide as a novel benign antifilarial agent

Search of potent antifilarial drugs has been a major thrust area in tropical medicine research over the decades. Herein, we report 4,7-dimethyl-3,4,7,8-tetrahydro-3λ⁶-[1,2]thiazino[4,3-f]quinoline-3,3,8-trione (8l) as a new class of antifilarial agent which is extremely potent, with lethality against all the developmental stages (oocyte, microfilaria and adult) of the filarial parasite Setaria cervi. Molecular investigation on its mode of action revealed that 8l is a typical inducer of reactive oxygen species that triggers oxidative stress inside the filarid and further signals induction of apoptosis by activating both intrinsic and extrinsic pathways. Moreover, 8l is also active against Wolbachia, the essential endosymbiont of several human infectious filarids. Selective toxicity against filarial parasites and non-toxic nature in rat model were found as unique traits of 8l to be a future medicine. Taken en masse, this maiden report on a novel quinolone fused cyclic sulfonamide presents a promising therapeutic lead for lymphatic filariasis in future.

The crystal structure of tetrakis(1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane-κP)silver(I) chloride dihydrate, C24H60AgClN12O6P4

C24H60AgClN12O6P4, tetragonal, P42/nmc (no. 137), a = 14.1874(3) Å, c = 9.8721(3) Å, V = 1987.08(1) Å3, Z = 2, R gt(F) = 0.0148, wR ref(F 2) = 0.0417, T = 100 K.

Design, Synthesis and in Vivo Evaluation of Novel Glycosylated Sulfonylureas as Antihyperglycemic Agents

Sulphonylurea compounds have versatile activities such as antidiabetic, diuretic, herbicide, oncolytic, antimalarial, antifungal and anticancer. The present study describes the design, synthesis and in vivo testing of novel glycosylated aryl sulfonylurea compounds as antihyperglycaemic agents in streptozocine-induced diabetic mice. The rational for the introduction of the glucosamine moiety is to enhance selective drug uptake by pancreatic β-cells in order to decrease the cardiotoxic side effect commonly associated with sulfonylurea agents. 2-Deoxy-2-(4-chlorophenylsulfonylurea)-d-glucopyranose was found to be the most potent antihyperglycaemic agents among the synthesized compounds in diabetic mice. This investigation indicates the importance of this novel class as potential antihyperglycaemic agents.

Improvement of antibacterial activity of some sulfa drugs through linkage to certain phthalazin-1(2H)-one scaffolds

RAB1 5 is a lead antibacterial agent in which trimethoprim is linked to phthalazine moiety. Similarly, our strategy in this research depends on the interconnection between some sulfa drugs and certain phthalazin-1(2H)-one scaffolds in an attempt to enhance their antibacterial activity. This approach was achieved through the combination of 4-substituted phthalazin-1(2H)-ones 9a, b or 14a, b with sulfanilamide 1a, sulfathiazole 1b or sulfadiazine 1c through amide linkers 6a, b to produce the target compounds 10a-d and 15a-e, respectively. The antibacterial activity of the newly synthesized compounds showed that all tested compounds have antibacterial activity higher than that of their reference sulfa drugs 1a-c. Compound 10c represented the highest antibacterial activity against Gram-positive bacteria Streptococcus pneumonia and Staphylococcus aureus with MIC = 0.39 μmol/mL. Moreover, compound 10d displayed excellent antibacterial activity against Gram-negative bacteria Escherichia coli and Salmonella typhimurium with MIC = 0.39 and 0.78 μmol/mL, respectively.

Synthesis and antimicrobial activity of novel heterocyclic sulfamoyl-phenyl-carboximidamides derived from clinically applied sulfonamides

A series of novel heterocyclic sulfamoyl-phenyl-carboximidamides were synthesized in satisfactory yields via condensation of clinically applied sulfonamides with heterocyclic methyl carbimidates. New structures were confirmed by IR and NMR spectra as well as elemental analyses. All the compounds were screened for their antibacterial, antifungal, and tuberculostatic activities. Preliminary results indicated that some target compounds exhibited promising antibacterial potency. Especially, N-[4-(thiazol-2-sulfamoyl)phenyl]pyrazine-2-carboximidamide (16) was found to be as potent as clinically applied sulfamethoxypyridazine.

Synthesis of novel aryl(heteroaryl)sulfonyl ureas of possible biological interest

The course of reaction of aryl and heteroaryl sulfonamides with diphenylcarbonate (DPC) and 4-dimethylaminopyridine (DMAP) was found to depend on the pKa of the sulfonamide used. Aryl sulfonamides with pK_a ~ 10 gave 4-dimethylamino-pyridinium arylsulfonyl-carbamoylides, while the more acidic heteroaryl sulfonamides (pK_a ~ 8) furnished 4-dimethylaminopyridinium heteroarylsulfonyl carbamates. Both the carbamoylides and carbamate salts reacted with aliphatic and aromatic amines with the formation of appropriate aryl(heteroaryl)sulfonyl ureas, and therefore, can be regarded as safe and stable substitutes of the hazardous and difficult to handle aryl(heteroaryl)sulfonyl isocyanates.

Review on supermolecules as chemical drugs

Supramolecular medicinal chemistry field has been a quite rapidly developing, increasingly active and newly rising interdiscipline which is the new expansion of supramolecular chemistry in pharmaceutical sciences, and is gradually becoming a relatively independent scientific area. Supramolecular drugs could be defined as medicinal supermolecules formed by two or more molecules through non-covalent bonds. So far a lot of supermolecules as chemical drugs have been widely used in clinics. Supermolecules as chemical drugs, i.e. supramolecular chemical drugs or supramolecular drugs, which might have the excellences of lower cost, shorter period, higher potential as clinical drugs for their successful research and development, may possess higher bioavailability, better biocompatibility and drug-targeting, fewer multidrug-resistances, lower toxicity, less adverse effect, and better curative effects as well as safety, and therefore exhibit wide potential application. These overwhelming advantages have drawn enormous special attention. This paper gives the definition of supramolecular drugs, proposes the concept of supramolecular chemical drugs, and systematically reviews the recent advances in the research and development of supermolecules, including organic and inorganic complex ones as chemical drugs in the area of antitumor, anti-inflammatory, analgesic, antimalarial, antibacterial, antifungal, antivirus, anti-epileptic, cardiovascular agents and magnetic resonance imaging agents and so on. The perspectives of the foreseeable future and potential application of supramolecules as chemical drugs are also presented.

Oxazoline chemistry — Part IV: Synthesis and characterization of oxazoline complexes of the zinc halides

The synthesis and characterization of 11 zinc halide derivatives that contain monodentate oxazoline ligands is described. The treatment of ether solutions of [ZnX2] (X = Cl, Br, I) with 2-aryl- or 2-methyl-2-oxazolines results in the formation of mildly hygroscopic complexes of the general formulae [ZnX2(ox)2] (ox = 2-methyl-2-oxazoline (1), 2,4,4-trimethyl-2-oxazoline (2), 2-phenyl-2-oxazoline (3), or 4,4-dimethyl-2-phenyl-2-oxazoline (4)), except in the case of ZnI2, which does not form an isolable complex — likely for steric reasons — with oxazoline 4. Treatment of [ZnBr2(4)2] with 1 reveals (1H NMR) that 1 only sluggishly displaces coordinated 4 at temperatures below 50 °C. The structural characterization, via single crystal X-ray diffraction, of six of the complexes, viz. [ZnI2(1)2], [ZnI2(2)2], [ZnX2(3)2] (X = Cl, Br, or I), and [ZnBr2(4)2], is also reported. All of these structurally characterized complexes are mononuclear zinc compounds with an overall distorted tetrahedral arrangement of the two halide and two oxazoline ligands around the zinc metal centre. The oxazoline series of complexes reported herein show little structural diversity, a facet which is in contrast to their substituted pyridine analogues.Key words: oxazoline, zinc, X-ray crystal structure, coordination complex, NMR spectroscopy, Zn(II).

Antimycobacterial activity of 3,4-dichlorophenyl-ureas, N,N-diphenyl-ureas and related derivatives

Substituted urea derivatives were prepared by reacting 3,4-dichlorophenyl isocyanate with amino acids, dipeptides, histamine or dicyandiamide among others, or from N,N-diphenyl-carbamoyl chloride and amino acids, dipeptides, or histamine. Other derivatives were obtained by reaction of PABA or PAS with arylsulfonyl halides. Some of the new compounds showed appreciable activity as antimycobacterial agents against Mycobacterium tuberculosis H37Rv, producing an inhibition of growth in the range of 80-89%, at a concentration of 6.25 microM. Some derivatives of this series might constitute interesting lead molecules for designing novel types of drugs effective against M. tuberculosis, a re-emerging pathogen both in the developed and under-developed countries.

Antimycobacterial activity of 9-sulfonylated/sulfenylated-6-mercaptopurine derivatives

A series of 9-sulfonylated/sulfenylated-6-mercaptopurines has been prepared by reaction of 6-mercaptopurine with sulfonyl/sulfenyl halides. These compounds constitute a new class of potent antimycobacterial agents, possessing MIC values against Mycobacterium tuberculosis H37Rv in the range of 0.39-3.39 microg/mL, as well as appreciable activity against Mycobacterium avium. Furthermore, a compound of this small series exhibited good activity (MIC under 1 microg/mL) against several drug resistant strains of M. tuberculosis.