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PubMed2005

Adsorption of phthalic acid and its esters onto high-area activated carbon-cloth studied by in situ UV-spectroscopy.

The adsorption behavior of phthalic acid and its three esters dimethyl phthalate, diethyl phthalate and diallyl phthalate onto high-area activated carbon-cloth was studied by in situ UV-spectroscopic technique. The effect of ionization of phthalic acid on its adsorption was examined by carrying out the adsorption process in three media; water, 1 M H(2)SO(4) and 0.005 M NaOH. Maximum adsorption was observed in 1 M H(2)SO(4) and almost no adsorption in 0.005 M NaOH. These results were discussed in terms of electrostatic and dispersion interactions between the adsorbate species and the carbon-cloth surface taking the point of zero charge (pH(pzc)) of the carbon-cloth into account. The adsorption process for the phthalate species studied was found to follow the first-order rate law, and the rate constants were determined. The isotherm data for the adsorption of phthalic acid and its esters were derived experimentally and fitted to Langmuir and Freundlich isotherm equations. Both equations were found to represent the experimental isotherm data almost equally well.

Adsorption↗
PubMed1980

Effects of phthalic acid monoesters on mouse testes.

Effects of phthalic acid monoesters on mouse testes have been studied. Testosterone concentrations in the testes on mice fed diets containing 2% of mono-n-butyl (MBP), mono-iso-butyl (MIBP), mono-2-ethylhexyl (MEHP) or mono-n-octyl phthalate (MOP) were lower than in control animals and relative testicular weights were increased in all mice except those which received MOP. Zinc concentration in the testes decreased in mice that received MBP, MIBP or MEHP.

Animals↗
PubMed2006

A new phthalic acid ester from Ajuga bracteosa.

A new phthalic acid ester 1,2-benzenedicarboxylic acid bis(2S-methyl heptyl) ester (1) was isolated from the hexane extract of the whole plant of Ajuga bracteosa. In addition, chloroform and methanol extracts yielded neo-clerodane diterpene ajugarin-I and two iridoid glycosides, reptoside and 8-O-acetyl harpagide. The structures of all the compounds were confirmed by extensive spectroscopic analysis. From the two oily fractions nine and six volatile constituents respectively were identified by GCMS. Linalyl acetate was found to be common in both the oil fractions. This plant is a new source of linalyl acetate, a valuable perfumery compound.

Ajuga↗
PubMed2005

Phthalic acid diamides activate ryanodine-sensitive Ca2+ release channels in insects.

Flubendiamide represents a novel chemical family of substituted phthalic acid diamides with potent insecticidal activity. So far, the molecular target and the mechanism of action were not known. Here we present for the first time evidence that phthalic acid diamides activate ryanodine-sensitive intracellular calcium release channels (ryanodine receptors, RyR) in insects. With Ca(2+) measurements, we showed that flubendiamide and related compounds induced ryanodine-sensitive cytosolic calcium transients that were independent of the extracellular calcium concentration in isolated neurons from the pest insect Heliothis virescens as well as in transfected CHO cells expressing the ryanodine receptor from Drosophila melanogaster. Binding studies on microsomal membranes from Heliothis flight muscles revealed that flubendiamide and related compounds interacted with a site distinct from the ryanodine binding site and disrupted the calcium regulation of ryanodine binding by an allosteric mechanism. This novel insecticide mode of action seems to be restricted to specific RyR subtypes because the phthalic acid diamides reported here had almost no effect on mammalian type 1 ryanodine receptors.

Animals↗
PubMed2006

Surface complexes of phthalic acid at the hematite/water interface.

The adsorption of o-phthalic acid at the hematite/water interface was investigated experimentally using batch adsorption experiments and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy over a wide range of solution pH, surface loading, and ionic strength conditions. Molecular orbital calculations for several possible surface complexes were also performed to assign atomistic structures to the features observed in the ATR-FTIR spectra. The results of the batch adsorption experiments exhibit typical anionic characteristics with high adsorption at low pH and low adsorption at high pH. The adsorption of phthalic acid also exhibits a strong dependence on ionic strength, which suggests the presence of outer-sphere complexes. ATR-FTIR spectra provide evidence of three fully deprotonated phthalate surface complexes (an outer-sphere complex and two inner-sphere complexes) under variable chemical conditions. A fully deprotonated outer-sphere complex appears to dominate adsorption in the circumneutral pH region, while two fully deprotonated inner-sphere complexes that shift in relative importance with surface coverage increase in importance at low pH. Comparison of experimental and theoretical calculations suggests the two inner-sphere complexes are best described as a mononuclear bidentate (chelating) complex and a binuclear bidentate (bridging) complex. The mononuclear bidentate inner-sphere complex was favored at relatively low surface coverage. With increasing surface coverage, the relative contribution of the binuclear bidentate inner-sphere complex increased in importance.

Journal Article↗
PubMed2003

Oxidative degradation of cardiotoxic anticancer anthracyclines to phthalic acids. Novel function or ferrylmyoglobin.

We show that the pseudoperoxidase activity of ferrylmyoglobin (MbIV) promotes oxidative degradation of doxorubicin (DOX), an anticancer anthracycline known to induce severe cardiotoxicity. MbIV, formed in vitro by reacting horse heart MbIII with H2O2, caused disappearance of the spectrum of DOX at 477 nm and appearance of UV-absorbing chromophores that indicated opening and degradation of its tetracyclic ring. Electron spray ionization mass spectrometry analyses of DOX/MbIV ultrafiltrates showed that DOX degradation resulted in formation of 3-methoxyphthalic acid, the product of oxidative modifications of its methoxy-substituted ring D. Other methoxy-substituted anthracyclines similarly released 3-methoxyphthalic acid after oxidation by MbIV, whereas demethoxy analogs released simple phthalic acid. Kinetic and stoichiometric analyses of reactions between DOX and MbIII/H2O2 or hemin/H2O2 showed that the porphyrin radical of MbIV-compound I and the iron-oxo moiety of MbIV-compound II were sequentially involved in oxidizing DOX; however, oxidation by compound I formed more 3-methoxyphthalic acid than oxidation by compound II. Sizeable amounts of 3-methoxyphthalic acid were formed in the heart of mice treated with DOX, in human myocardial biopsies exposed to DOX in vitro, and in human cardiac cytosol that oxidized DOX after activation of its endogenous myoglobin by H2O2. Importantly, H9c2 cardiomyocytes were damaged by low concentrations of DOX but could tolerate concentrations of 3-methoxyphthalic acid higher than those measured in murine or human myocardium. These results unravel a novel function for MbIV in the oxidative degradation of anthracyclines to phthalic acids and suggest that this may serve a salvage pathway against cardiotoxicity.

Animals↗
PubMed2002

Analysis of mono- and diesters of o-phthalic acid by solid-phase extractions with polystyrene-divinylbenzene-based polymers.

Retention mechanisms of an unmodified and a hydroxylated polystyrene-divinylbenzene polymer were studied by solid-phase extraction of o-phthalic acid and some of its mono- and diesters from purified water and then analysing by GC-MS. The monoesters and phthalic acid were retained only when protonated (i.e. acidified with HCI to pH 0.9). Of all elution solvents tested, ethyl acetate gave the best overall recoveries (61-89%) with both polymers. Applicability to complex matrixes (e.g. acidogenic landfill leachates) was examined by introducing a washing step with acetone in acidified water (pH 0.9) to eliminate volatile fatty acids (C2-C6) from the cartridge. Finally, the method was tested on real samples.

Esters↗
PubMed2004

[Preparation and properties of complex of europium lanthanum with crown ether and p-phthalic acid].

Two complexes of crown ether europium (EuL) and crown ether lanthanum (LaL) were synthesized by europium perchlorate and lanthanum perchlorate with 18-crown-6(18-C-6) respectively. The heternuclear complexes of europium-lanthanum p-phthalic acid crown ether were prepared by the two complexes (EuL and LaL) with p-phthalic acid. The elemental analysis shows that its composition is EuLaL2L'(ClO4)4.6H2O(L = 18-C-6 and L' = p-C6H4 (COO)2). The IR spectra, UV-spectra and molar conductor indicate that both ligands (L and L') coordinate rare earth ions (Eu3+ and La3+), but perchlorate group is free. The fluorescence spectra show that the fluorescence intensities of the complex of heternuclear (EuLaL2L'(ClO4)4.6H2O) are more than eight times that of the crown ether europium complex. It was shown that the linked ligand (p-phthalic acid) can transfer the absorbed energy of Lanthanum-crown ether to europium-crown ether with high efficiency.

Crown Ethers↗
PubMed2006

Adsorption of phthalic acid and salicylic acid and their effect on exchangeable Al capacity of variable-charge soils.

Low-molecular-weight (LMW) organic acids may be adsorbed by soils and the adsorption could affect their biodegradation and efficiency in many soil processes. In the present study, the adsorption of phthalic acid and salicylic acid and their effect on the exchangeable Al capacity of variable-charge soils were investigated. The results indicated that phthalic acid and salicylic acid were adsorbed by four variable-charge soils to some extent, oxisols showed a greater adsorption capacity for organic acids than ultisols, and the ability of the four variable-charge soils to adsorb the organic acids at different pH generally followed the order Kunming oxisol > Xuwen oxisol > Jinxian ultisol > Lechang ultisol, which was closely related to their content of free iron oxides and amorphous iron and aluminum oxides. The adsorption of organic acids induced a decrease in the zeta potentials of soils and oxides. Goethite has greater adsorption capacity for organic acid than Xuwen oxisol and the adsorption of organic acids resulted in a bigger decrease in the zeta potential of goethite suspensions. After free iron oxides were removed, less organic acid was adsorbed by Xuwen oxisol and no change was observed in zeta potential for the soil suspension after organic acid was added. The presence of phthalic acid increased the capacity of exchangeable Al and the increment in the four variable-charge soils also followed the order Kunming oxisol > Xuwen oxisol > Lechang ultisol and Jinxian ultisol. The presence of salicylic acid increased the capacity of exchangeable Al in Kunming oxisol, Xuwen oxisol, and Jinxian ultisol, but decreased it in Lechang ultisol due to less adsorption of the acid and formation of soluble Al-salicylate complexes in solution. After free iron oxides were removed, less effect of organic acid on exchangeable Al was observed for Xuwen oxisol, which further confirmed that the iron oxides played a significant role in organic acid adsorption and had a consequent effect on the capacity of exchangeable Al in variable-charge soils. Therefore, the higher the content of iron oxides, the greater the adsorption of organic acids by soils and the greater the increase in soil exchangeable Al induced by the organic acids.

Journal Article↗
PubMed1996

Anaerobic degradation of phthalic acid esters during digestion of municipal solid waste under landfilling conditions.

Anaerobic microorganisms in municipal solid waste samples from laboratory-scale landfill reactors and a pilot-plant biogas digestor were investigated with the aim of assessing their ability to transform four commercially used phthalic acid esters (PAEs) and phthalic acid (PA). The PAEs studied were diethyl phthalate (DEP), butylbenzyl phthalate (BBP), dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP). No biological transformation of DEHP could be detected in any of the experiments. Together with waste samples from the simulated landfilling conditions, the PAEs (except DEHP) were hydrolytically transformed to their corresponding monoesters. These accumulated as end products, and in most cases they were not further degraded. During incubation with waste from the biogas digestor, the PAEs (except DEHP) were completely degraded to methane and carbon dioxide. The influence of the landfill development phase on the transformations was investigated utilizing PA and DEP as model substances. We found that during both the intense and stable methanogenic (but not the acidogenic) phases, the microorganisms in the samples had the potential to transform PA. A shorter lag phase was observed for the PA transformation in the samples from the stable methanogenic phase as compared with earlier phases. This indicates an increased capacity to degrade PA during the aging phases of the municipal solid waste in landfills. No enhancement of the DEP transformation could be observed as conditions in the methanogenic landfill model changed over a year's time. The results indicate that microorganisms developing in a methanogenic landfill environment have a substantially lower potential to degrade compared with those developing in a biogas reactor.

Anaerobiosis↗
PubMed1980

Effect of phthalic acid esters on mouse testes.

Effects of three phthalic acid esters (PAEs) on mouse testes are described and discussed. Zinc concentrations in the testes of mice fed a diet containing 2% dibutyl (DBP), di-iso-butyl (DIBP) or di-2-ethylhexyl phthalate (DEHP) were less than those of control animals. Testosterone concentrations in the testes were decreased in DEHP-treated mice, and the relative testis weight of DBP-, DIBP- and DEHP-treated mice was increased.

Animals↗
PubMed1977

Phthalic acid esters in various foodstuffs and biological materials.

Phthalic acid esters (PAEs) are ubiquitous environmental contaminants in Japan. Di-n-butyl phthalate (DNBP) and di-2-ethylhexyl phthalate (DEHP) are the most commonly found of nine PAEs examined. DNBP and DEHP residues in 22 kinds of commerical foodstuffs (55 examples), mostly in plastic containers, are recorded. The level is generally higher in powdered foodstuffs than in other materials and the content of PAEs increased sharply during their storage. A close correlation is found between the content of PAE residues in packing materials and those of foodstuffs. The levels of DNBP and DEHP in human blood samples are found to be much higher than those of PCBs.

Adult↗
PubMed2000

Endocrine disrupting chemicals, phthalic acid and nonylphenol, activate Pregnane X receptor-mediated transcription.

Recently, Pregnane X receptor (PXR), a new member of the nuclear receptor superfamily, was shown to mediate the effects of several steroid hormones, such as progesterone, glucocorticoid, pregnenolone, and xenobiotics on cytochrome P450 3A genes (CYP3A) through the specific DNA sequence for CYP3A, suggesting that PXR may play a role in steroid hormone metabolism. In this paper, we demonstrated that phthalic acid and nonylphenol, endocrine-disrupting chemicals (EDCs), stimulated PXR-mediated transcription at concentrations comparable to those at which they activate estrogen receptor-mediated transcription using a transient reporter gene expression assay in COS-7 cells. However, bisphenol A, another EDC, had no effect on PXR-mediated transcription, although this chemical significantly enhanced ER-mediated transcription. In the yeast two-hybrid protein interaction assay, PXR interacted with two nuclear receptor coactivator proteins, steroid hormone receptor coactivator-1 and receptor interacting protein 140, in the presence of phthalic acid or nonylphenol. Thus, EDC-occupied PXR may regulate its specific gene expression through the receptor-coactivator interaction. In contrast, these EDCs had no effect on the interaction between PXR and suppressor for gal 1, a component of proteasome. Finally, the expression of CYP3A1 mRNA in the liver of rats exposed to phthalic acid or nonylphenol markedly increased compared with that in rats treated with estradiol, bisphenol A, or ethanol as assessed by competitive RT-PCR. These data suggest that EDCs may affect endocrine functions by altering steroid hormone metabolism through PXR.

Animals↗
PubMed1985

Circulating concentrations of di(2-ethylhexyl) phthalate and its de-esterified phthalic acid products following plasticizer exposure in patients receiving hemodialysis.

The degree of exposure to the plasticizer di(2-ethylhexyl) phthalate (DEHP) was assessed in 11 patients undergoing maintenance hemodialysis for the treatment of renal failure. The amount of DEHP leached from the dialyzer during a 4-hr dialysis session was estimated by monitoring the DEHP blood concentration gradient across the dialyzer. Circulating concentrations of the biologically active products of DEHP de-esterification, viz., mono(2-ethylhexyl) phthalate (MEHP) and phthalic acid, were also determined during the dialysis session. On the average, an estimated 105 mg of DEHP was extracted from the dialyzer during a single dialysis session, with a range of 23.8 to 360 mg. The rate of extraction of DEHP from the dialyzer was correlated with serum lipid content as expressed by the sum of serum cholesterol and triglyceride concentrations (r = +0.65, p less than 0.05). Time-averaged circulating concentrations of MEHP during dialysis (1.33 +/- 0.58 micrograms/ml) were similar to those of DEHP (1.91 +/- 2.11 micrograms/ml). Blood concentrations of phthalic acid (5.22 +/- 3.94 micrograms/ml) were higher than those of the esters. The length of time patients had been receiving regular dialysis treatment was not a determinant of circulating concentrations of DEHP or MEHP. In contrast, time-averaged circulating concentrations of phthalic acid correlated strongly with the duration (in years) of dialysis treatment (r = +0.92, p less than 0.001). The results indicated substantial exposure to DEHP during hemodialysis and that the de-esterified products of DEHP are present in significant concentrations in the systemic circulation. Further study is needed to assess the contribution of these metabolites to the biological actions of DEHP in man.

Adult↗
PubMed1990

[The breakdown of phthalic acid esters by microorganisms].

The distribution in environment of phthalic acid esters classified according to their inherent toxicity, teratogenic, mutagenic properties and cancerogenic activity into a group of priority pollutants of biosphere is described in this review. The role of microbial community in degradation of phthalate esters has been demonstrated. The effect of such environmental factors as pH of the medium, temperature, humidity, concentration of organic matter, the introduction of promising microbial strains in natural biocenoses has been examined. The pathways of phthalate ester metabolism have been analysed in representatives of active bacterial destructors belonging to genera Nocardia, Pseudomonas and Micrococcus. The decomposition rate of phthalate esters has been shown to be correlated with structure, concentration and culture conditions.

Bacteria↗
PubMed2003

Degradation of anthracene by Mycobacterium sp. strain LB501T proceeds via a novel pathway, through o-phthalic acid.

Mycobacterium sp. strain LB501T utilizes anthracene as a sole carbon and energy source. We analyzed cultures of the wild-type strain and of UV-generated mutants impaired in anthracene utilization for metabolites to determine the anthracene degradation pathway. Identification of metabolites by comparison with authentic standards and transient accumulation of o-phthalic acid by the wild-type strain during growth on anthracene suggest a pathway through o-phthalic acid and protocatechuic acid. As the only productive degradation pathway known so far for anthracene proceeds through 2,3-dihydroxynaphthalene and the naphthalene degradation pathway to form salicylate, this indicates the existence of a novel anthracene catabolic pathway in Mycobacterium sp. LB501T.

Anthracenes↗
PubMed2005

Enrichment of Pb(II) ions using phthalic acid functionalized XAD-16 resin as a sorbent.

A simple and reliable method has been developed using polymeric material containing phthalic acid as a chelating agent to concentrate ultratrace amounts of lead ions in aqueous solutions. After characterization by CHN, IR, and thermal studies, the static and dynamic sorption behavior of Pb(II) ions onto new synthetic resin has been investigated. The sorption has been optimized with respect to pH, shaking speed, and contact time between the two phases. Maximum sorption is achieved from solution of pH 5-8 after 10 min agitation time. The lowest concentration for quantitative recovery is 5.8 ng cm(-3) with a preconcentration factor of approximately 850. The kinetics of sorption follows the first-order rate equation with the rate constant k=0.58+/-0.04 min(-1). The variation of the equilibrium constant K(c) with temperature between 10 and 50 degrees C yields values of DeltaH, 52.4+/-1.65 kJmol(-1), DeltaS, 186+/-5.21 Jmol(-1)K(-1), and DeltaG(303K), -4.15+/-0.002 kJmol(-1). The sorption data of Pb(II) ions in the concentration range from 2.41x10(-6) to 1.44x10(-4) molL(-1) follows the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms at all temperatures investigated. The sorption of Pb(II) ions onto synthesized resin in the presence of common anions and cations has also been measured. The possible sorption mechanism of Pb(II) ions onto phthalic acid modified XAD-16 is also discussed. The sorption procedure is utilized to preconcentrate Pb(II) ions prior to their determination in automobile exhaust particulates by atomic absorption spectrometry using direct and standard addition methods.

Journal Article↗