Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Azulenes”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2004

Phototoxicity and DNA damage induced by the cosmetic ingredient chemical azulene in human Jurkat T-cells.

Previous study showed that the cosmetic ingredient chemical azulene and its derivative gauiazulene exhibited photomutagenicity four- to five-fold higher than spontaneous mutation in Salmonella typhimurium TA102. In this study, phototoxicity including photogenotoxicity of azulene in human Jurkat T-cells is reported. When the cell suspensions are irradiated by light (UVA plus visible light) in the presence of azulene, an azulene dose-dependent cellular DNA damage is observed. At the highest azulene concentration of 50 microM, the average DNA fragmentation is 33 +/- 10%, determined by single cell gel electrophoresis (Comet assay). Cell viability assay using fluorescein diacetate indicates that the cells could endure the damage and remain viable. Further study revealed that the combination of light and azulene can cause single-strand cleavage on pure PhiX174 plasmid DNA in solution. Studies using scavengers reveal that singlet oxygen and free radicals are involved in causing DNA cleavage. This suggests that the photomutagenicity of azulene in S. typhimurium TA102 could be due to DNA fragmentation caused by the concurrent exposure to azulene and light.

Azulenes↗
PubMed1993

Azulenic retinoids: novel nonbenzenoid aromatic retinoids with anticancer activity.

Several novel azulene-containing retinoids were prepared and evaluated for their ability to suppress carcinogen-induced neoplastic transformation and to concomitantly up-regulate gap junctional communication in the in vitro mouse fibroblast C3H/10T1/2 cell bioassay. The azulenic retinoids were divided into two groups: compounds 1-6 were modeled after retinoic acid with flexible polyenic side chain whereas retinoids 7-13 featured a benzoic acid moiety analogous to the prototypic retinobenzoate (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2- naphthalenyl)-1-propenyl]benzoic acid (TTNPB). Within this latter group the side chains for compounds 7, 10, and 11 were attached at the 1-, 2-, and 8-positions of the azulenic terminus, respectively. Biological activities were determined for all the new compounds. Two of these novel retinoids, azulenic retinobenzoic acid derivatives 7 and 11, were completely effective inhibitors of transformation at 10(-6) M. The most active azulenic retinoids also enhanced gap junctional communication in untransformed cells; this was associated with up-regulated expression of connexin 43, a structural protein of the gap junction. Two fluorinated analogs were also tested. The azulenic fluoro acid 5 was found to be more potent than the trifluoromethyl analog 6. Azulenic analogs with hydroxyl or carboxaldehyde side chain functional groups were ineffective transformation inhibitors. In general, azulenic retinobenzoic acid analogs structurally akin to TTNPB were more effective than flexible side chain analogs related to retinoic acid.

Animals↗
PubMed2005

Effect of sodium azulene sulfonate on capsaicin-induced pharyngitis in rats.

Sodium azulene sulfonate is a water-soluble derivative of azulene which is an antiinflammatory component of chamomile of the family of Asteraceae. Sodium azulene sulfonate is clinically used as a therapeutic agent in the treatment of pharyngitis as well as other inflammatory diseases such as tonsillitis, stomatitis and conjunctivitis. There has been no documentation on the effect of sodium azulene sulfonate on pharyngitis in laboratory models, probably because of no availability of such models. We recently established a pharyngitis model using capsaicin application on pharyngeal mucosa in rats. The present study investigated the antipharyngitis activity of sodium azulene sulfonate comparing with those of ruthenium red (vanilloid receptor antagonist, 8.5 and 85 mg/ml), ascorbic acid (antioxidative compound, 100 microg/ml), povidone iodine (gargle as disinfectant, oxidative compound, 5 and 20 mg/ml) and diclofenac sodium (cyclooxygenase inhibitor, 0.1 and 1 mg/ml). As an antipharyngeal effect, the capsaicin-induced plasma exudation in the pharyngeal mucosa of the rat was evaluated. The capsaicin-induced plasma exudation in the pharyngeal mucosa was inhibited by sodium azulene sulfonate (100 and 200 microg/ml) as well as ruthenium red and ascorbic acid, but not by povidone iodine and dicrofenac sodium; povidone iodine rather promoted the plasma exudation. In conclusion, the antipharyngitis effect of sodium azulene sulfonate was demonstrated for the first time in a laboratory model. Although the mechanism by which sodium azulene sulfonate inhibited the capsaicin-induced pharyngitis is not yet unraveled, antioxidative effect, but not inhibitory effect on cyclooxygenase pathway, might be involved.

Animals↗
PubMed2004

Intramolecular vibrational energy redistribution in bridged azulene-anthracene compounds: ballistic energy transport through molecular chains.

Intramolecular vibrational energy flow in excited bridged azulene-anthracene compounds is investigated by time-resolved pump-probe laser spectroscopy. The bridges consist of molecular chains and are of the type (CH(2))(m) with m up to 6 as well as (CH(2)OCH(2))(n) (n=1,2) and CH(2)SCH(2). After light absorption into the azulene S(1) band and subsequent fast internal conversion, excited molecules are formed where the vibrational energy is localized at the azulene side. The vibrational energy transfer through the molecular bridge to the anthracene side and, finally, to the surrounding medium is followed by probing the red edge of the azulene S(3) absorption band at 300 nm and/or the anthracene S(1) absorption band at 400 nm. In order to separate the time scales for intramolecular and intermolecular energy transfer, most of the experiments were performed in supercritical xenon where vibrational energy transfer to the bath is comparably slow. The intramolecular equilibration proceeds in two steps. About 15%-20% of the excitation energy leaves the azulene side within a short period of 300 fs. This component accompanies the intramolecular vibrational energy redistribution (IVR) within the azulene chromophore and it is caused by dephasing of normal modes contributing to the initial local excitation of the azulene side and extending over large parts of the molecule. Later, IVR in the whole molecule takes place transferring vibrational energy from the azulene through the bridge to the anthracene side and thereby leading to microcanonical equilibrium. The corresponding time constants tau(IVR) for short bridges increase with the chain length. For longer bridges consisting of more than three elements, however, tau(IVR) is constant at around 4-5 ps. Comparison with molecular dynamics simulations suggests that the coupling of these chains to the two chromophores limits the rate of intramolecular vibrational energy transfer. Inside the bridges the energy transport is essentially ballistic and, therefore, tau(IVR) is independent on the length.

Journal Article↗
PubMed2003

The azulene-to-naphthalene rearrangement revisited: a DFT study of intramolecular and radical-promoted mechanisms.

Intramolecular and radical-promoted mechanisms for the rearrangement of azulene to naphthalene are assessed with the aid of density functional calculations. All intramolecular mechanisms have very high activation energies (>/=350 kJ mol(-1) from azulene) and so can only be competitive at temperatures above 1000 degrees C. Two radical-promoted mechanisms, the methylene walk and spiran pathways, dominate the reaction below this temperature. The activation energy for an orbital symmetry-allowed mechanism via a bicyclobutane intermediate is 382 kJ mol(-1). The norcaradiene-vinylidene mechanism that has been proposed in order to explain the formation of small amounts of 1-phenyl-1-buten-3-ynes from flash thermolysis of azulene has an activation energy of 360 kJ mol(-1); subtle features of the B3LYP/6-31G(d) energy surface for this mechanism are discussed. All intermediates and transition states on the spiran and methylene walk radical-promoted pathways have been located at the B3LYP/6-31G(d) level. Interconversion of all n-H-azulyl radicals via hydrogen shifts was also examined, and hydrogen shifts around the five-membered ring are competitive with the mechanisms leading to rearrangement to naphthalene, but those around the seven-membered ring are not. Conversion of a tricyclic radical to the 9-H-naphthyl radical is the rate-limiting transition state on the spiran pathway, and lies 164.0 kJ mol(-1) above that of the 1-H-azulyl radical. The transition state for the degenerate hydrogen shift between the 9-H-azulyl and 10-H-azulyl radicals is 7.4 kJ mol(-1) lower. Partial equilibration of the intermediates in the spiran pathway via this shift may therefore occur, and this can account for the surprising formation of 1-methylnaphthalene from 2-methylazulene. The rate-limiting transition state for the methylene walk pathway involves the concerted transfer of a methylene group from one ring to the other and lies 182.3 kJ mol(-1) above that of the 1-H-azulyl radical. It is shown that rearrangement via a combination of 31% methylene walk and 69% spiran pathways can account semiquantitatively for all the products from 1-(13)C-azulene, 9-(13)C-azulene, and 4,7-(13)C(2)-azulene, in addition to accounting for the products from methylazulenes, and the formation of naphthalene-d(0) and -d(2) from azulene-4-d. It is also pointed out that a small extension to the spiran pathway could provide an alternative explanation for the formation of 1-phenyl-1-buten-3-ynes.

Journal Article↗
PubMedDate not supplied

Relationship between electronic structure and cytotoxic activity of azulenes.

The structure-activity relationship of the cytotoxic activity of azulene and azulene derivatives was discussed, using theoretically calculated results. In order to clearly divide the azulenes into three groups according to their functional groups, the CC50, four different dipole moments (muG, muESP-G, muwand muESP-W) and heats of formation (deltaHf) of the azulenes [1-24] were separately calculated in two states, gas-phase and water, by the conductor-like screening model/parametric method 3 (COSMO/PM3). For the halogenated azulenes and isopropyl azulenes, the cytotoxic activity might follow the three quantitative structure-activity relationship (QSAR) parameters: deltadeltaHf, HOMO energy and muw Whereas, for the other ten compounds [3-5, 7-8, 10, 15-18], the cytotoxic activity might be related to the three QSAR parameters, deltadeltaHf, LUMO energy and muG

Antineoplastic Agents↗
PubMed2003

Photomutagenicity of cosmetic ingredient chemicals azulene and guaiazulene.

The photomutagenicity of the popular skin conditioning agents azulene and guaiazulene were tested in Salmonella typhimurium TA98, TA100 and TA102. Following irradiation with UVA and/or visible light, both azulene and guaiazulene exhibited mutagenicity 4-5-fold higher than the spontaneous background mutation. In contrary, naphthalene, a structural isomer of azulene, was not photomutagenic under the same conditions. Azulene was photomutagenic when irradiated with UVA light alone, visible light alone, or a combination of UVA and visible light. Azulene and guaiazulene are not mutagenic when the experiment is conducted with the exclusion of light. Therefore, extreme care must be taken when using cosmetic products with azulene/guaiazulene as ingredients since after applying these products on the skin, exposure to sunlight is inevitable.

Azulenes↗
PubMed2003

Synthesis, stabilities, and redox behavior of Di(1-azulenyl)(6-azulenyl)methylium hexafluorophosphates. Generation of a donor-acceptor-substituted neutral radical by azulenes.

Several di(1-azulenyl)(6-azulenyl)methanes and 1,3-bis[(1-azulenyl)(6-azulenyl)methyl]azulenes were prepared by the condensation reaction of azulenes with diethyl 6-formylazulene-1,3-dicarboxylate under acidic conditions. The products were converted into di(1-azulenyl)(6-azulenyl)methylium hexafluorophosphates and azulene-1,3-diylbis[(1-azulenyl)(6-azulenyl)methylium] bis(hexafluorophosphate)s via hydride abstraction reaction with DDQ following the exchange of counterions. These mono- and dications exhibited high stability with large pK(R)(+) values (5.6-10.1), despite the captodative substitution of azulenes. The electrochemical reduction of the monocations upon cyclic voltammetry (CV) exhibited a reversible two-step, one-electron reduction wave with a small difference between the first reduction potential (E(1)(red)) and the second one (E(2)(red)), which exhibited the generation of highly amphoteric neutral radicals in solution. The electrochemical reduction of dications showed voltammograms, which were characterized by subsequent two single-electron waves and a two-electron transfer upon CV attributable to the formation of a radical cation, a diradical (or twitter ionic structure), and a dianionic species, respectively. Formation of a persistent neutral radical from a monocation was revealed by ESR and UV-vis spectroscopies and theoretical calculations. The ESR spectra of the neutral radical gave two hyperfine coupling constants: a(H) = 0.083 (6H) and 0.166 mT (9H) (g = 2.0024), indicating that an unpaired electron delocalizes over all three of the azulene rings. The stable monoanion, which shows the localization of the charge on the 6-azulenyl substituent, was also successfully generated from the di(1-azulenyl)(6-azulenyl)methane derivative.

Journal Article↗
PubMed2005

Vibrational energy relaxation of azulene studied by the transient grating method. I. Supercritical fluids.

The vibrational energy dissipation process of the ground-state azulene in supercritical xenon, carbon dioxide, and ethane has been studied by the transient grating spectroscopy. In this method, azulene in these fluids was photoexcited by two counterpropagating subpicosecond laser pulses at 570 nm, which created a sinusoidal pattern of vibrationally hot ground-state azulene inside the fluids. The photoacoustic signal produced by the temperature rise of the solvent due to the vibrational energy relaxation of azulene was monitored by the diffraction of a probe pulse. The temperature-rise time constants of the solvents were determined at 383 and 298 K from 0.7 to 2.4 in rho(r), where rho(r) is the reduced density by the critical density of the fluids, by the fitting of the acoustic signal based on a theoretical model equation. In xenon, the temperature-rise time constant was almost similar to the vibrational energy-relaxation time constant of the photoexcited solute determined by the transient absorption measurement [D. Schwarzer, J. Troe, M. Votsmeier, and M. Zerezke, J. Chem. Phys. 105, 3121 (1996)] at the same reduced density irrespective of the solvent temperature. On the other hand, the temperature-rise time constants in ethane were larger than the vibrational energy-relaxation time constants by a factor of about 2. In carbon dioxide, the difference was small. From these results, the larger time constants of the solvent temperature rise than those of the vibrational energy relaxation in ethane and carbon dioxide were interpreted in terms of the vibrational-vibrational (V-V) energy transfer between azulene and solvent molecules and the vibrational-translational (V-T) energy transfer between solvent molecules. The contribution of the V-V energy transfer process against the V-T energy transfer process has been discussed.

Journal Article↗
PubMed2003

Highly substituted azulene dyes as multifunctional NLO and electron-transfer compounds.

Two highly substituted azulene derivatives were synthesised by Pd-mediated dimerisation from the corresponding tolan species. One azulene derivative (2) has donor functionalities (dianisylaminophenyl and dianisylamino) in the 1-, 2-, 3- and 6-positions, while the other (1) has donors (dianisylaminophenyl) in the 2- and 6-positions and acceptors (nitrophenyl) in the 1- and 3-positions. Each azulene derivative shows strong bond length alternation in the solid state, determined by X-ray crystal analysis, and an intense CT band around 450-500 nm in its UV/Vis spectrum. The first-order hyperpolarisability of 1 and of 2 was measured by hyper-Rayleigh scattering and is about that of disperse red DR1. Both azulene derivatives show multiple oxidation processes. The intramolecular adiabatic ET behaviour of the mixed valence radical cations of 1 and of 2 was investigated by UV/Vis/NIR spectroelectrochemistry. The intervalence-CT band of 1(+) could be analysed by the Generalised Mulliken-Hush theory, which yields an electronic coupling V=1140 cm(-1) for the optically induced adiabatic hole transfer.

Journal Article↗
PubMed1993

Design, synthesis, and pharmacology of 3-substituted sodium azulene-1-sulfonates and related compounds: non-prostanoid thromboxane A2 receptor antagonists.

A series of novel azulene-1 carboxylic acid derivatives 28-30, azulene-1 sulfonic acid sodium salts 41a-c, and related compounds were synthesized. These compounds were tested for TXA2 receptor antagonistic activity. The inhibitory concentrations (IC50) of these compounds for vascular contraction (TXA2 tau receptor) and platelet aggregation (TXA2 alpha receptor) induced by (15S)-15-hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5(Z),13(E)- dienoic acid (U-46619) were obtained. Azulene-1-sulfonic acid sodium salts 41a-c were over 3 times more potent than azulene-1-carboxylic acids 28-30. The most potent compound, 41b was 4 orders of magnitude more potent than a TXA2 antagonist, BM13,177, in inhibiting vascular contraction (tau receptor) and had an IC50 of 9.0 x 10(-10) M. Compound 41b was also found to be a tau receptor selective antagonist (IC50 of contraction/IC50 of aggregation = 378) and to have no TXA2 synthetase inhibitory activity at concentrations up to 10(-4) M and no partial agonistic activity at concentrations up to 10(-5) M in rabbit aorta (tau receptor) and up to 10(-4) M in rabbit platelet-rich plasma (alpha receptor). In a radioligand binding assay using rabbit gel-filtered platelets, compound 41b had a high-affinity binding for the TXA2 receptor. In an in vivo study, compound 41b inhibited U-46619-induced sudden death in mice at a dose of 0.3 mg/kg and its duration of action was over 8 h when administered orally at 3 mg/kg.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2000

[Study of the electronic transitions of azulene and several of it's derivitives and their auto-association by the monopole-dipole atomic interaction (AMDI) model].

The corresponding hydrogen, carbon and nitrogen atomic dipolar polarisabilities and effective charges given by Fraga are used for the determination of theoretical UV absorption spectra of azulene, 1,3-diaza-azulene and 2-phenyl-1,3-diaza-azulene and their self-associations. These spectra are obtained for the first time using the atom monopole dipole interaction model and compared to those given experimentally by other authors.

Azulenes↗
PubMed2002

Synthesis of new azulene derivatives and study of their effect on lipid peroxidation and lipoxygenase activity.

The relationship between free radicals and acute or chronic inflammation has been well established. We have previously reported the significant antioxidant activity of the natural azulene derivatives chamazulene and guaiazulene. Furthermore, some synthetic azulene analogues have been found to possess anti-inflammatory activity. In this investigation we report the synthesis of five 3-alkyl or 3-(hydroxy)alkylazulene-1-carboxylic acids and esters, from tropolone, via the corresponding furanone. The synthesised compounds were tested for their effect on the peroxidation of rat hepatic microsomal membrane lipids, applying the 2-thiobarbituric acid test. Their anti-inflammatory activity was evaluated in vitro by the offered inhibition of soybean lipoxygenase. All the tested molecules were found to inhibit lipid peroxidation by 100% at 1 mM. They were also found to considerably inhibit lipoxygenase activity. The above results are discussed in relation to the structure and physicochemical properties of the examined azulene derivatives.

Animals↗
PubMed1981

Metabolism of azulene in rats.

1. Azulene was rapidly metabolized in the rat and excreted in the urine as the sulphate conjugate of 1-hydroxyazulene; 45% of the dose was recovered as pure metabolite from the 0-24 h urine. 2. [1,3(-2)H2]Azulene was converted in vivo to 1-hydroxyazulene sulphate which was shown by 1H-n.m.r. spectroscopy to contain one deuterium at C-3 and essentially no detectable deuterium at C-2. This result suggests that, if a 1,2-oxide of azulene was an intermediate in the 1-hydroxylation, it rearranged with direct loss of deuterium from C-1 rather than an NIH shift to C-2.

Animals↗
PubMedDate not supplied

Inhibition of LPS-stimulated NO production in mouse macrophage-like cells by azulenes.

We investigated the effect of twenty-seven azulenes on nitric oxide (NO) production by mouse macrophage-like Raw 264.7 cells. No azulene derivative alone induced NO production by the Raw 264.7 cells, but inhibited lipopolysaccharide (LPS)-stimulated NO production to various extents. The ability of azulenes to inhibit NO generation by activated macrophages was generally increased when their cytotoxic activity declined. Western blot and RT-PCR analyses demonstrated that the most potent compound, 1,3-difluoroazulene [11], slightly inhibited the expression of inducible NO synthase (iNOS), but only at extremely high concentrations. ESR spectroscopy showed that [11] did not produce radical under alkaline condition, nor scavenged O2- (generated by HX-XOD reaction) or NO (generated by NOC-7). These data suggest that the inhibitory effect of [11] may be produced via a mechanism other than iNOS induction and a radical-mediated mechanism.

Animals↗
PubMed2000

Azo-azulene derivatives as second-order nonlinear optical chromophores

The molecular and solid state nonlinear optical (NLO) properties of several (phenylazo)-azulenes are investigated. In particular, (4-nitrophenylazo)-azulene (2b) exhibits a quadratic hyperpolarizability (beta(vec)) of 80 x 10(-30) cm5esu recorded at 1.907 microm by the electric field-induced second-harmonic (EFISH) technique. This molecular material, which crystallizes in the monoclinic noncentrosymmetric space group Pc, exhibits an efficiency 420 times that of urea in second-harmonic generation. The origin of the optical nonlinearity in azo-azulene is discussed in relation with crystal structures and semiempirical calculations within the INDO/SOS formalism, and compared with that of the well known disperse red one (DR1) organic dye.

Journal Article↗
PubMed2004

A convenient synthetic route to benz[cd]azulenes: versatile ligands with the potential to bind metals in an eta5, eta6, or eta7 fashion.

A facile method for preparing the 2H-benz[cd]azulene system, based upon an elaboration of the guaiazulene framework, is presented. Aerial oxidation to the corresponding 8-(2-propylidene)-benz[cd]azulene, and also cycloaddition reactions with tetracyanoethylene (TCNE), are described. The first X-ray crystal structure of a 2H-benz[cd]azulene, as an eta6-coordinated Cr(CO)3 complex, is reported.

Journal Article↗
PubMed2006

Energy transfer between polyatomic molecules. 3. Energy transfer quantities and probability density functions in self-collisions of benzene, toluene, p-xylene and azulene.

This paper is the third and last in a series of papers that deal with collisional energy transfer, CET, between aromatic polyatomic molecules. Paper 1 of this series (J. Phys. Chem. B 2005, 109, 8310) reports on the mechanism and quantities of CET between an excited benzene and cold benzene and Ar bath. Paper 2 in the series (J. Phys. Chem., in press) discusses CET between excited toluene, p-xylene and azulene with cold benzene and Ar and CET between excited benzene colliding with cold toluene, p-xylene and azulene. The present work reports on CET in self-collisions of benzene, toluene, p-xylene and azulene. Two modes of excitation are considered, identical excitation energies and identical vibrational temperatures for all four molecules. It compares the present results with those of papers 1 and 2 and reports new findings on average vibrational, rotational, and translational energy, , transferred in a single collision. CET takes place mainly via vibration to vibration energy transfer. The effect of internal rotors on CET is discussed and CET quantities are reported as a function of temperature and excitation energy. It is found that the temperature dependence of CET quantities is unexpected, resembling a parabolic function. The density of vibrational states is reported and its effect on CET is discussed. Energy transfer probability density functions, P(E,E'), for various collision pairs are reported and it is shown that the shape of the curves is convex at low temperatures and can be concave at high temperatures. There is a large supercollision tail at the down wing of P(E,E'). The mechanisms of CET are short, impulsive collisions and long-lived chattering collisions where energy is transferred in a sequence of short internal encounters during the lifetime of the collision complex. The collision complex lifetimes as a function of temperature are reported. It is shown that dynamical effects control CET. A comparison is made with experimental results and it is shown that good agreement is obtained.

Journal Article↗