In vitro evaluation of the amoebicidal activity of rosemary (Rosmarinus officinalis L.) and cloves (Syzygium aromaticum L. Merr. & Perry) essential oils against Acanthamoeba polyphaga trophozoites

Several species of the genus Acanthamoeba cause human diseases. Treatment of infections involves various problems, emphasising the need to develop alternative antiprotozoal agents. We studied the anti-amoebic activity of Essential Oils (EOs), derived from rosemary (Rosmarinus officinalis L.) and cloves (Syzygium aromaticum L. Merr. & Perry), against Acanthamoeba polyphaga strain. The amoebicidal activity of cloves and rosemary EOs was preliminary demonstrated by the morphology change (modifications in the cell shape, the presence of precipitates in the cytoplasm, autophagic vesicles, membrane blends) of the treated trophozoites. The cell-counts, carried out after staining trophozoites with a Trypan blue solution, revealed that both EOs were active in a dose-dependent manner and in relation to the exposure time. This activity was evident after few hours, with encouraging results obtained in particular with cloves EO, able to act at the lower concentrations and after 1 h, probably for its high eugenol content (65.30%).     

An Unusual Product from the Reaction of C(PPh3)2 with [Mn2(CO)10]: Formation and Crystal Structure of [Mn(OPPh3)2{O2CC(PPh3)2}2][Mn(CO)5]2

The carbodiphosphorane C(PPh₃)₂ ( 1 ) reacts with [Mn₂(CO)₁₀] in THF to produce quantitatively the salt‐like complex (HC{PPh₃}₂)[Mn(CO)₅] ( 2 ) as THF solvate. If the reaction is carried out in 1,2‐dimethoxyethane (DME) small amounts of [Mn(OPPh₃)₂{O₂CC(PPh₃)₂}₂][Mn(CO)₅]₂ ( 3 ) as DME solvate along with solvent free 2 as the main product were isolated. Proton abstraction from the solvent led to the formation of 2 ; the ligands OPPh₃ and O₂CC(PPh₃)₂}₂ of 3 are the results of a side reaction from [Mn₂(CO)₁₀] and 1 in a Wittig type manner. From the reaction in benzene small amounts of 3 were also obtained, crystallizing as benzene solvate 3· 4C₆H₆. The crystal structures of 2· THF, 2 , 3· 1.75DME and 3· 4C₆H₆ are reported. The compounds are further characterized by IR and ³¹P NMR spectroscopy.     

Terpyridine–Porphyrin Hetero‐Pacman Compounds

The two different coordination spheres afforded by Pacman architectures offer cooperativity derived from two different metal centers. A modular strategy is developed to produce a hetero‐Pacman scaffold featuring a porphyrin and terpyridine for metal‐ion binding. A double Suzuki reaction was employed to first attach a terpyridine moiety to a xanthene backbone and then attach a porphyrin. The new hetero‐Pacman scaffold has been characterized and all building blocks have been isolated and structurally characterized. The principle objective to incorporate different metal centers was confirmed by isolating a trinuclear complex comprising two porphyrinic units and a bis(terpyridine)–iron unit. The compounds described herein expand the Pacman scaffold concept by allowing for the incorporation of a terpyridine–metal complex proximate to a porphyrin‐cofactor active site for small‐molecule activation.     

Analysis of furanocoumarins from Yemenite Dorstenia species by liquid chromatography/electrospray tandem mass spectrometry

A series of prevailing prenylated furanocoumarins from leaves of Dorstenia gigas and Dorstenia foetida (Moraceae) were investigated by liquid chromatography/electrospray tandem mass spectrometry. The mass spectral behavior of the furanocoumarins under positive ion electrospray conditions is discussed using both an ion trap and a triple quadrupole system. It is demonstrated that both methods represent valuable tools not only for the rapid classification of this type of compounds, but also with respect to their substitution pattern.     

Probing small parton densities in ultraperipheral A A and pA collisions at the CERN large Hadron Collider

We calculate photoproduction rates for several hard processes in ultraperipheral proton-lead and lead-lead collisions at the CERN Large Hadron Collider (LHC) with square root of sNN = 8.8 and 5.5 TeV, respectively, which could be triggered in the large LHC detectors. We use ATLAS as an example. The lead ion is treated as a source of (coherently produced) photons with energies and intensities greater than those of equivalent ep collisions at the DESY collider HERA. We find very large rates for both inclusive and diffractive production that will extend the HERA x range by nearly an order of magnitude for similar virtualities. We demonstrate that it is possible to reach the kinematic regime where nonlinear effects are larger than at HERA.     

Scanning electron microscopy examination of endothelium morphology in human carotid plaques

In recent years, experimental and clinical evidence has been provided regarding endothelial dysfunction and its contribution to the inflammatory process leading to atherosclerotic plaque formation. All the techniques employed direct to the study of endothelial dysfunction, however usually require isolation of endothelial cells and therefore tissue manipulation and destruction, with subsequent loss of information regarding morphology and topographical distribution of the lesions.By means of scanning electron microscopy (SEM), we have investigated the characteristics of the endothelial layer in carotid specimens obtained from subjects undergoing carotid endarterectomy. Carotid specimens obtained from 6 patients undergoing carotid endarterectomy for stenosis ≥ 70% were fixed, prepared and examined by use of SEM in a direct mode.All the plaque specimens showed increased thickness of subendothelial connective tissue with respect to post-mortem tissue obtained from an healthy subject. Endothelial layers were typically detached from the basal lamina surface and infiltrating cells (mainly erythrocytes and, possibly, monocytes) could be identified. Endothelial cells in proximity of the plaques had irregular shape, with prominent nuclei. In several areas, the endothelial layer was completely absent and basal lamina completely uncovered.In the present study, by using SEM analysis, the morphological features of dysfunctional endothelium in human carotid plaques were extensively documented at the ultrastructural level. SEM is a powerful investigational technique which allows tridimensional examination of specimens without disruption of the originary morphology.     

Nucleobases modified azo‐polysiloxanes,materials with potential application in biomolecules nanomanipulation

Here we show the possibility to obtain azopolysiloxanes modified with nucleobases (adenine and thymine) with potential application in immobilization and nanomanipulation of biomolecules. We propose a photofluidization mechanism based on the concept of the conformational instability, which can explain the presence of the fluid state below the glass transition. The azopolymers were characterized by ¹H NMR, GPC, DSC, DTG, UV spectroscopy, AFM analysis, and molecular simulations. Depending on the type of nucleobase used, the surface of the azopolysiloxane film can be structured in different ways under UV irradiation. Photoisomerization studies in solid state were carried out to demonstrate the influence of the operational conditions (presence or absence of natural visible light) on the polymeric film UV response. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4240–4248, 2007     

Synthesis and cytotoxicity of silylalkylthio‐substituted N‐heterocycles and their hydroselenites

New hydroselenites of the different silylalkylthio‐substituted N‐heterocycles have been prepared by the reaction of selenium dioxide with N‐heterocycles in an aqueous medium. Their structure was confirmed by ¹H, ¹³C, and ⁷⁷Se NMR data. Most of these silylalkylthio‐substituted N‐heterocycles and their hydroselenites have an expressed cytotoxic activity on the MG‐22A (mouse hepatoma), HT‐1080 (human fibrosarcoma), B16 (mouse melanoma), and Neuro 2A (mouse neuroblastoma) cell lines. Some of the hydroselenites exhibit free‐radical protection simultaneously with a high cytotoxic effect. The substances studied were also active in vivoagainst sarcoma S‐180. Copyright © 2003 John Wiley & Sons, Ltd.     

A Novel Pentadentate Redox‐Active Ligand and Its Iron(III) Complexes: Electronic Structures and O2 Reactivity

A novel redox‐active ligand, H₄^Ph2SL^AP ( 1 ) which was designed to be potentially pentadentate with an O,N,S,N,O donor set is described. Treatment of 1 with two equivalents of potassium hydride gave access to octametallic precursor complex [H₂^Ph2SL^APK₂(thf)]₄ ( 2 ), which reacted with FeCl₃ to yield iron(III) complex [H₂^Ph2SL^APFeCl] ( 3 ). Employing Fe[N(SiMe₃)₂]₃ for a direct reaction with 1 led to ligand rearrangement through C?S bond cleavage and thiolate formation, finally yielding [HL^APFe] ( 5 ). Upon exposure to O₂, 3 and 5 are oxidized through formal hydrogen‐atom abstraction from the ligand NH units to form [^Ph2SL^SQFeCl] ( 4 ) and [L^SQFe] ( 6 ) featuring two or one coordinated iminosemiquinone moieties, respectively. Mössbauer measurements demonstrated that the iron centers remain in their +III oxidation states. Compounds 3 and 5 were tested with respect to their potential as models for the catechol dioxygenase. Thus, they were treated with 3,5‐di‐tert‐butyl‐catechol, triethylamine and O₂. It turned out that the iron–catecholate complexes react with O₂ in dichloromethane at ambient conditions through C?C bond cleavage mainly forming extradiol cleavage products. Intradiol products are only side products and quinone formation becomes negligible. This observation has been rationalized by a dissociation of two donor functions upon coordination of the catecholate.