Metal complexes of a novel heterocyclic benzimidazole ligand formed by rearrangement-cyclization of the corresponding Schiff base. Electrosynthesis, structural characterization and antimicrobial activity.

The electrochemical oxidation of anodic metals (M = cobalt, nickel, copper, zinc and cadmium) in a solution of the ligand 1H-anthra[1,2-d]imidazol-6,11-dione-2-[2-hydroxyphenyl] [H2L] afforded homoleptic [ML] compounds. The addition to the electrochemical cell of coligands (L') such as 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen) allowed the synthesis, in one step, of heteroleptic [MLL'] compounds. The crystal structures of H2L (1), [CoL(MeOH)]2 (2), [CoL(phen)]2 (3), [NiL(bpy)]2 (4), [CuL(bpy)] (5), [CuL(phen)] (6) and [CdL(bpy)]2 (7) have been determined by X-ray diffraction techniques. The crystal structures of 2, 3, 4 and 7 consist of dimeric species in which both metallic atoms are connected through two phenolate bridges in a penta-coordinated (2) or hexa-coordinated (3, 4 and 7) environment. Copper compounds 5 and 6 are monomeric species with the metal in a pentacoordinated [N4O] environment. In all the compounds, the main interactions responsible for the crystal packing are classic (N-HO, O-HN and O-HO) and non-classic (C-HO and C-HN) hydrogen bond interactions, and π interactions (π-π-stacking and C-Hπ). All compounds were also characterized by microanalysis, IR spectroscopy, FAB mass spectrometry and 1H NMR spectroscopy. Magnetic susceptibility data were measured for 2-4 over the temperature range 2-300 K, and their analysis has revealed the occurrence of intramolecular antiferromagnetic coupling for 2 (J = -2 cm-1) and ferromagnetic coupling for 3 (J = 7.8 cm-1) and 4 (J = 2.8 cm-1) [J being the isotropic magnetic coupling parameter]. The nature of the magnetic coupling in 2-4 is correlated with the magnitude of the M-Ophenolate-M angle between the phenolate bridge and the metallic centers [M(ii) = Co, Ni]. The in vitro antimicrobial properties of the novel ligand and its metal complexes were detected against Gram positive and Gram negative bacteria and fungi. [NiL(bpy)]2 and all tested Cd(ii) complexes were the most active compounds, showing the highest inhibitory effect against bacilli (MIC 1.5-3 µg mL-1) and Sarcina, Streptococci and Haemophilus influenzae bacterial strains (MIC 12-50 µg mL-1), while almost no antifungal properties were observed.

Thermoneutral housing is a critical factor for immune function and diet-induced obesity in C57BL/6 nude mice.

OBJECTIVES: Obesity-related cancers represent public health burdens of the first order. Nevertheless, suitable mouse models to unravel molecular mechanisms linking obesity to human cancer are still not available. One translational model is the immunocompromised Foxn1 (winged-helix/forkead transcription factor) nude mouse transplanted with human tumor xenografts. However, most xenograft studies are conducted in nude mice on an in-bred BALB/c background that entails protection from diet-induced obesity. To overcome such resistance to obesity and its sequelae, we here propose the dual strategy of utilizing Foxn1 nude mice on a C57BL/6 background and housing them at their thermoneutral zone. METHODS: C57BL/6 nude and corresponding wild-type mice, housed at 23 or 33 °C, were subjected to either low-fat diet or high-fat diet (HFD). Energy expenditure, locomotor activity, body core temperature, respiratory quotient as well as food and water intake were analyzed using indirect calorimetry. Immune function at different housing temperatures was assessed by using an in vivo cytokine capture assay. RESULTS: Our data clearly demonstrate that conventional housing protects C57BL/6 nude mice from HFD-induced obesity, potentially via increased energy expenditure. In contrast, HFD-fed C57BL/6 nude mice housed at thermoneutral conditions develop adiposity, increased hepatic triglyceride accumulation, adipose tissue inflammation and glucose intolerance. Moreover, increased circulating levels of lipopolysaccharide-driven cytokines suggest a greatly enhanced immune response in C57BL/6 nude mice housed at thermoneutrality. CONCLUSION: Our data reveals mild cold stress as a major modulator for energy and body weight homeostasis as well as immune function in C57BL/6 nude mice. Adjusting housing temperatures to the thermoneutral zone may ultimately be key to successfully study growth and progression of human tumors in a diet-induced obese environment.

Decreased number of circulating endothelial progenitor cells in patients with Graves' hyperthyroidism.

OBJECTIVE: A relevant biological role of circulating endothelial progenitor cells (EPC) was recently demonstrated. EPC are generated in the bone marrow, and interact with damaged endothelium, restoring the integrity of the monolayer. Therefore, aim of the present study was to evaluate EPC in the blood of patients with untreated Graves' hyperthyroidism (GD), in whom an increased oxidative stress was observed. DESIGN AND METHODS: Twenty-three patients with untreated active GD and 18 matched normal controls (NC) were included in the study. Circulating EPC were isolated from peripheral blood. Mononuclear cells were cultured with endothelial basal medium supplemented with EGM SingleQuots, and were identified by positive double staining after 7 days in culture. Circulating levels of C reactive protein, total antioxidant power, interleukin (IL)-6, IL- 18, monocyte chemoattractant protein-1, tumor necrosis facotr- α, soluble vascular cell adhesion molecule (VCAM) and intracellular adhesion molecule were evaluated by enzymelinked immunosorbent assay kit. EPC number was also evaluated in a subgroup of GD patients after restoration of euthyroidism. RESULTS: Systolic blood pressure resulted increased in GD patients compared with control subjects whereas diastolic blood pressure was not significantly different. Patients with GD showed an increase in circulating levels of IL-18 and VCAM-1 and a reduction of total antioxidant power (p<0.05) compared to NC. Moreover, a reduced number of EPC was observed in patients with GD compared to NC (p<0.05) which turned to NC values after restoring euthyroidism. CONCLUSION: Patients with GD showed a reduction in the physiological protective mechanisms against endothelial damage, probably induced by increased inflammation and oxidative stress.

Antimicrobial and mutagenic properties of organotin(IV) complexes with isatin and N-alkylisatin bisthiocarbonohydrazones.

A new series of ligands is synthesised starting from thiocarbonohydrazide and isatin (H(2)itc) or N-alkylisatin (methyl, H(2)mtc; butyl, H(2)btc; pentyl, H(2)ptc); the X-ray structure of H(2)mtc is discussed. The bis imine ligands are reacted with diorganotin(IV) compounds, obtaining monometallic complexes. In order to establish unequivocally their coordination geometry, the X-ray structures of (C(2)H(5))(2)Sn(Hmtc)Cl.THF (THF, tetrahydrofuran) and (C(6)H(5))Sn(Hptc)Cl(2) are determined. In (C(2)H(5))(2)Sn(Hmtc)Cl.THF, the ligand results monodeprotonated and, essentially, monodentate through the sulphur atom, while in (C(6)H(5))Sn(Hptc)Cl(2) the ligand is still monodeprotonated but SNO tridentate. The organotin(IV) complexes of isatin and N-methylisatin exhibit good antibacterial activity, better than that of the corresponding N-butyl and N-pentylisatin derivatives. Gram positive bacteria are the most sensitive microorganisms. No growth inhibition of fungi is detected up to the concentration of 100 microg/ml. H(2)mtc shows mutagenic activity with and without metabolic activation, whereas no mutagenicity is found for its organotin complexes and for the other compounds.

In vitro and in vivo study of 5-methoxypsoralen skin concentration after topical application.

The aim of this work was to study the skin distribution of 5-methoxypsoralen (5-MOP) after application of topical gels, in vitro and in vivo, in both healthy and psoriatic skin sites of 6 psoriatic patients. Drug skin distribution was determined using the thin slicing technique and subsequent HPLC analysis. In the presence of dermatological disease, i.e. psoriasis, the permeability of the tissue changed considerably, leading to an important increase in the cumulative amount of 5-MOP recovered in the skin after topical application. The amount of 5-MOP found in vitro in the human skin was intermediate between those cumulated in healthy and psoriatic skin sites during an in vivo experiment. The gel formulation is an efficacious carrier for the topical photochemotherapy of psoriasis with 5-MOP, since it allows drug penetration in psoriatic skin.

Effect of drying methods on retention of moist sucralfate gel properties.

The aim of this work was to find a drying procedure for moist sucralfate gel capable of producing dried sucralfate gel that retains the original gel properties of bioadhesion, rheology, and micromeritics. Spray-drying and microwave-drying procedures were employed. Mannitol was used as a gel-protective substance during the drying processes. The spray drying of moist sucralfate gel gave rise to a powder whose water suspensions showed significantly reduced viscosity. The bioadhesion of spray-dried sucralfate gel was strongly reduced by drying. When mannitol was used as a gel protector, the spray-dried sucralfate in part maintained the original bioadhesion of moist sucralfate gel. The preparation of a dried sucralfate gel retaining the bioadhesion characteristics, avoiding the use of mannitol, was made possible using the microwave-drying procedure. The microwave-dried product possesses a granular morphology suitable for direct compression because it is a free flowing and strongly coherent granular powder.

Antimicrobial and genotoxic activities of N-(2-hydroxyethyl)-1,2-benzisothiazol-3(2H)-thione carbamic esters.

The antimicrobial properties of N-(2-hydroxyethyl)-1,2-benzisothiazol-3(2H)-thione (1a,b) and its carbamic esters 2a,b-6a,b were tested in vitro against Gram positive and Gram negative bacteria, yeasts and dermatophytes. All compounds markedly inhibit the growth of Gram positive bacteria exhibiting MIC values ranging from 1.25 to 10 micrograms/ml. A strong antifungal activity is exerted against dermatophytes with MICs, in general, between 0.7 and 12 micrograms/ml. Structure-activity relationship studies show that these compounds are, in most cases, more effective than the corresponding benzisothiazolone analogues 7-12. None of the tested compounds shows genotoxic properties by Bacillus subtilis rec-assay and Salmonella-microsome test.

Cellular toxicity of N-substituted 2,2'-dicarboxamidodiphenyldisulphides with high antimicrobial activity.

In the present paper we evaluate the cellular toxicity of some N-substituted 2,2'-dicarboxamidodiphenyldisulphides with high antimicrobial activities, in view of their potential application in humans or animals. The toxicological studies have been conducted in the murine cell line of 3T3 fibroblasts as eucaryotic cellular model. Our results have allowed the identification of a series of derivatives exhibiting antimicrobial activity and low cellular toxicity. Structure-cytotoxic activity relationships are also discussed.

Antimicrobial and mutagenic activity of some carbono- and thiocarbonohydrazone ligands and their copper(II), iron(II) and zinc(II) complexes.

Several mono- and bis- carbono- and thiocarbonohydrazone ligands have been synthesised and characterised; the X-ray diffraction analysis of bis(phenyl 2-pyridyl ketone) thiocarbonohydrazone is reported. The coordinating properties of the ligands have been studied towards Cu(II), Fe(II), and Zn(II) salts. The ligands and the metal complexes were tested in vitro against Gram positive and Gram negative bacteria, yeasts and moulds. In general, the bisthiocarbonohydrazones possess the best antimicrobial properties and Gram positive bacteria are the most sensitive microorganisms. Bis(ethyl 2-pyridyl ketone) thiocarbonohydrazone, bis(butyl 2-pyridyl ketone)thiocarbonohydrazone and Cu(H2nft)Cl2 (H2nft, bis(5-nitrofuraldehyde)thiocarbonohydrazone) reveal a strong activity with minimum inhibitory concentrations of 0.7 microgram ml-1 against Bacillus subtilis and of 3 micrograms ml-1 against Staphylococcus aureus. Cu(II) complexes are more effective than Fe(II) and Zn(II) ones. All bisthiocarbono- and carbonohydrazones are devoid of mutagenic properties, with the exception of the compounds derived from 5-nitrofuraldehyde. On the contrary a weak mutagenicity, that disappears in the copper complexes, is exhibited by monosubstituted thiocarbonohydrazones.

Antimicrobial activity of some 1,2-benzisothiazoles having a benzenesulfonamide moiety.

Some sulfonamide and sulfonylurea derivatives of unsubstituted and 5-methylsubstituted 1,2-benzisothiazole were studied in vitro for their antimicrobial properties against bacteria and fungi. Compounds 7 and 8 exhibited good antibacterial activity against Gram positive bacteria. A strong synergism was observed when their growth-inhibitory effect was assayed in combination with trimethoprim by using Bacillus subtilis and Staphylococcus aureus as test microorganisms. The antimycotic action of benzenesulfonylurea derivative 9 was very marked for Madurella mycetomatis and dermatophytes Epidermophyton floccosum, Microsporum gypseum and Trichophyton spp.. Structure-activity relations are discussed.

Organotin complexes with pyrrole-2,5-dicarboxaldehyde bis(acylhydrazones). Synthesis, structure, antimicrobial activity and genotoxicity.

Mono- and bimetallic organotin complexes with pyrrole-2,5-dicarboxaldehyde bis(2-hydroxybenzoylhydrazone) (H5dfps) and pyrrole-2,5-dicarboxaldehyde bis(2-picolinoylhydrazone) (H3dfpp) were synthesized and characterized by IR, 1H and 119Sn NMR spectroscopy. X-ray analysis of the complex [Sn(H3dfps)(C6H5)2].(CH3)2SO revealed a pentacoordination around tin through a N,N,O terdentate ligand behaviour of the hydrazone. This complex is the most active compound, exhibiting MIC values of 3 and 12 micrograms/ml against Gram positive and Gram negative bacteria, respectively. None of the ligands or complexes produced DNA-damage in the Bacillus subtilis rec-assay or showed mutagenic activity in the Salmonella-microsome test.

Organotin complexes with pyrrole-2-carboxaldehyde monoacylhydrazones. Synthesis, spectroscopic properties, antimicrobial activity, and genotoxicity.

A series of organotin complexes with pyrrole-2-carboxaldehyde 2-hydroxybenzoylhydrazone (H3mfps) and pyrrole-2-carboxaldehyde 2-picolinoylhydrazone (H2mfpp) was investigated. The IR, 1H, and 119Sn nuclear magnetic resonance spectroscopic characterization of all the compounds is reported and discussed in connection with the ligand behaviour of the hydrazone and the structure of the organotin complex. Complexes exhibit antibacterial properties higher than those of the corresponding ligands but they turn out to be less potent than the parent organotin compounds. Sn(H3mfps) (C6H5)2Cl2.2H2O and Sn(Hmfpp)(n-C4H9)2Cl are the most active antibacterial compounds showing MIC values between 3-6 micrograms/ml against Bacillus subtilis and Staphylococcus aureus and between 6-25 micrograms/ml against Escherichia coli; the first compound also strongly inhibits the growth of Aspergillus niger. All the ligands and complexes are devoid of DNA-damaging activity in the Bacillus subtilis rec-assay. H2mfpp and its complexes Sn(Hmfpp)(C2H5)2Cl and Sn3(Hmfpp)(mfpp) (C6H5)3Cl6 are shown by the Salmonella-microsome assay to be mutagenic substances in the presence of a metabolic activation system. The obtained results are discussed on the basis of structure-activity relationships.

Evaluation of preservative effectiveness in pharmaceutical products: the use of a wild strain of Pseudomonas cepacia.

A sodium benzoate-sorbic acid preservative system of a pharmaceutical product was proved effective against a wild strain of Pseudomonas cepacia, following the official method of the Italian and British Pharmacopoeias. However, this preservative system was ineffective against a challenge of Ps. cepacia wild strain cells grown in the unpreserved pharmaceutical product and on culture media different from those described by the Pharmacopoeias. The adaptive resistance of the wild strain of Ps. cepacia was not demonstrated with a laboratory strain (ATCC 25609). In contrast, p-hydroxybenzoate-based preservative systems proved to be efficient in protecting the pharmaceutical product against a challenge of wild and laboratory strains of Ps. cepacia grown in the different conditions described above. The results obtained suggest the usefulness, in the official methods for testing pharmaceutical preservatives, of using wild microbial strains isolated from the pharmaceutical environment. Metabolic adaptive responses, capable of affecting the antimicrobial sensitivity of wild micro-organisms used to challenge the preserved product, can be detected by using cells grown in the unpreserved pharmaceutical product.

Antimicrobial and genotoxic activities of N-hydroxyalkyl-1, 2-benzisothiazol-3(2H)-one carbamic esters.

N-Hydroxyethyl- and N-hydroxypropyl-1,2-benzisothiazol-3(2H)-one carbamic esters were prepared in order to test their activity against representative bacterial and fungal strains. The obtained results were compared with those reported for parent alcohols and some interesting considerations were drawn. None of the studied derivatives possess genotoxic activity in the Bacillus subtilis rec-assay and Salmonella-microsome test.

Synthesis, antimicrobial and genotoxic properties of some benzoimidazole derivatives.

A number of 1H-benzoimidazol-2-ylamine and of 1-methyl-1H-benzoimidazol-2-ylamine derivatives were synthesized and the crystal and molecular structure of N-[4-(2-amino-benzoimidazole-1-sulfonyl)-phenyl] acetamide was determined by X-ray diffraction analysis. The compounds obtained were investigated for antimicrobial and genotoxic activities.

Synthesis and antimicrobial activity of N-(1,2-benzisothiazol-3-yl)amidines.

Several N-(1,2-benzisothiazol-3-yl)amidines were synthesized and examined for their in vitro antimicrobial activity. Some of the compounds studied were effective against bacteria and fungi. Amidines carrying unsaturated alkylic chains showed the highest antimicrobial activity, the propenyl derivative 7 proving to be the most potent with minimum inhibitory concentrations of 25 micrograms/ml against Gram positive bacteria and mould and of 3-12 micrograms/ml against yeasts. The results indicate that an unsaturated moiety is an important function for enhancing the antimicrobial activity in the compounds under investigation.

Guiera senegalensis J. F. Gmelin (Combretaceae): Biological activities and chemical investigation.

Guiera senegalensis J. F. Gmelin (Combretaceae) leaves are used in African traditional medicine for gastrointestinal disorders, cough and topically for wound healing. This paper regards the evaluation of antiradical, antielastase, antimicrobial, genotoxic and antimutagenic activities of the leaf extracts and the determination of chemical structure of the elastase inhibitors. Antimicrobial activity was tested against Gram positive and negative bacteria, moulds and yeasts. Genotoxic potential was assayed with Bacillus subtilis rec -assay and Salmonella-microsome test. The latter was used also for determining antimutagenic activity. Antiradical properties were evaluated as inhibition of ADP-Fe(2+) induced lipoperoxidation in rat liver microsomes. Porcine pancreatic elastase was used to test enzyme inhibition. The methanolic extract was fractionated with dichloromethane, w-butanol and water and these fractions were tested for the above mentioned activities. The crude extract possessed a mild antimicrobial effect only on Gram positive bacteria (MIC 0.8-1.5 mg/ml) and the effect was associated to dichloromethane and n-butanol fractions. The crude extract and the dichloromethane and n-butanol fractions were weakly genotoxic but showed also a significant antimutagenicity. Inhibition of lipoperoxidation was assignable mainly to the n-butanol fraction. Elastase was inhibited (IC(50) 181 µg/ml) and the inhibition was retained in the water soluble fraction (IC(50) 37µg/ml). The compounds responsible for the enzyme inhibition were a mixture of proanthocyanidins constituted predominantly by (-)-epicatechin and (-)-epigallocatechin units. The mean degree of polymerization was 2-6.

Biological studies on 1,2-benzisothiazole derivatives VI Antimicrobial activity of 1,2-benzisothiazole and 1,2-benzisothiazolin-3-one derivatives and of some corresponding 1,2-benzisoxazoles.

Numerous 1,2-benzisothiazole and 1,2-benzisothiazolin-3-one derivatives, variously substituted in the different positions of the molecule, were tested for their in vitro antimicrobial activity. Some corresponding 1,2-benzisoxazoles and 1,2-benzisoxazolin-3-ones were also considered. Several compounds possess a potent and broad antibacterial and antifungal activity, particularly against Gram positive microorganisms, yeasts and dermatophytes. 1,2-Benzisothiazolin-3-ones were found to be the most active substances. On the contrary, the benzisoxazoles and the benzisoxazolin-3-ones considered were devoid of activity. The results obtained are discussed on the basis of structure-activity relationships.

Biological studies on 1,2-benzisothiazole derivatives V. Antimicrobial properties of N-alkanoic, N-arylalkanoic and N-aryloxyalkanoic derivatives of 1,2-benzisothiazolin-3-one: QSAR study and genotoxicity evaluation.

N-alkanoic, N-arylalkanoic and N-aryloxyalkanoic acids of 1,2-benzisothiazolin-3-one, esters and amides of N-arylalkanoic and N-aryloxyalkanoic acids and 1,1-dioxide derivatives of N-arylalkanoic acids and esters were investigated in vitro antimicrobial activity. N-arylalkanoic and N-aryloxyalkanoic acids (compounds 4-12) and their esters and amides (compounds 13-26) exhibited a good antimicrobial activity against Gram positive bacteria, with several compounds showing potencies 10-20 times higher than 1,2-benzisothiazolin-3-one. None of the chemicals tested inhibited the growth of E. coli. Yeasts and moulds possess a considerable susceptibility to compounds 12-23. The logP (octanol-water) of esters and amides of N-arylalkanoic and N-aryloxyalkanoic acids were measured by the shake-flask technique and the potencies against Gram positive bacteria of the compounds tested was related to their lipophilicity. QSAR analysis showed a bilinear relation, with a logD0 around 3 for the activity on B. subtilis. The phenoxyacetic and phenoxybutyric acid derivatives are positive outliers, showing a potency higher than that predicted from their lipohilicity. The most active compounds were further tested against different Gram positive bacteria and moulds, including Bacilli, Sarcina lutea, Staphylococcus epidermidis, Candida spp. and dermatophytes. The antibacterial and antifungal activity was specific for 1,2-benzisothiazolin-3-ones, the corresponding 1,1-dioxide derivatives being inactive. The genotoxic properties of the compounds studied were evaluated by the Bacillus subtilis rec-assay and Salmonella-microsome test. None of the compounds showed DNA-damaging or mutagenic activity.

Synthesis, structure, and biological activity of organotin compounds with di-2-pyridylketone and phenyl(2-pyridyl) ketone 2-aminobenzoylhydrazones.

The ligand behavior of di-2-pyridylketone 2-aminobenzoylhydrazone (Hdpa), and phenyl(2-pyridyl)ketone 2-aminobenzoylhydrazone (Hdba) towards organotin derivatives was investigated. The synthesis and the IR and 119Sn NMR spectroscopic characterization of the compounds is reported, together with the X-ray crystal structures of Hdpa and Sn(C6H5)3Cl(OH2).Hdpa, which are discussed and compared. The in vitro evaluation of antimicrobial properties revealed the strong activity of Sn(C6H5)2(Hdpa)Cl2 and Sn(C6H5)3Cl(OH2).Hdpa complexes. None of the compounds showed genotoxicity in the Bacillus subtilis rec-assay and in the Salmonella-microsome test.