Sorption and manganese-induced oxidative coupling of hydroxylated aromatic compounds by natural geosorbents

The sorption/desorption equilibria and solvent extractabilities of phenol, o-cresol, and p-chlorophenol with respect to natural sorbents having different types of soil organic matter were investigated. Parallel tests in systems amended with birnessite (delta-MnO2), a solid-phase oxidative coupling catalyst, were also conducted. Sorption/desorption isotherms and solvent extraction data reveal that the relative isotherm linearities, desorption hysteresis, and extractabilities of these compounds are related to the geochemical nature of the sorbent organic matter and to the existence of system conditions that promote oxidative coupling reactions. When suitable coupling catalysts are present, soils containing primarily diagenetically "young" and highly amorphous organic matter (e.g., humic materials) are more likely to retain those solutes than are those containing primarily diagenetically "old" and more condensed organic matter (e.g., kerogens). The sorption/desorption properties of the solutes were significantly altered in the presence of birnessite as a result of both cross-coupling reactions with reactive soil organic matter components and self-coupling reactions with each other to form polymeric species. Under appropriate conditions, mineral-catalyzed oxidative coupling may exert a dominant influence on the sorption and transport of hydroxylated aromatic compounds in soil and sediment systems.     

Occurrence of polycyclic aromatic hydrocarbons and their hydroxylated metabolites in infant foods

Eleven polycyclic aromatic hydrocarbons (PAHs) have been analysed in commercial milk formulae and infant cereals. Two hydroxylated PAHs metabolites (1-OH-Pyr and 3-OH-B[a]P) and their conjugates were also analysed in milk samples. To determine the selected PAH metabolites, a simple, fast quantitative and economic method was developed. This method comprising ultrasound-assisted solvent extraction, enzymatic hydrolysis, solid-phase clean-up and detection by liquid chromatography with fluorescence detection (LC–FD) and liquid chromatography tandem mass spectrometry (LC–MS/MS) as confirmatory technique. The method was evaluated by constructing calibration curves, measurement of recovery, precision and the limits of detection. The purpose of this survey was to determine the selected analytes, to assess the exposure of babies and infants and to produce data for comparison with proposed limits that were being considered at the time of the survey. The results showed that not only no samples would have exceeded the limit for benzo[a]pyrene which is used as an indicator for the presence of PAHs, but also no hydroxy PAH metabolites have been detected.     

Photocatalytic degradation of aromatic pollutants: a pivotal role of conduction band electron in distribution of hydroxylated intermediates

The modulation of the yield distribution of intermediates formed in the photocatalytic degradation of organic pollutants is of extreme importance for the application of photocatalysis in environmental cleanup, as different intermediates usually exhibit distinct biological toxicity and secondary reactivity. In this paper, we report that the distribution of monohydroxylated intermediates (m-, p- and o-) formed during the photocatalytic oxidation of aromatic compounds changes with the variation of reaction conditions, such as O(2) partial pressure and substrate concentration. By detailed product analysis, theoretical calculation, and oxygen isotope labeling experiments, we show that these changes are due to the selective reduction of HO-adduct radicals (the precursors of hydroxylated intermediates) by conduction band electrons (e(cb)(-)) back to the original substrate, that is, p- and o-HO-adduct radicals are more susceptible to e(cb)(-) than the m- one. Our experiments give an example that, even under oxidative conditions, the yield distribution of isomeric intermediates can be modulated by e(cb)(-)-initiated reduction. This study also illustrates that the unique redox characteristics of photocatalysis, that is, both oxidation and reduction reactions take place on or near the surface of a single nanoparticle, can provide opportunities for the reaction control.     

Milk and urine excretion of polycyclic aromatic hydrocarbons and their hydroxylated metabolites after a single oral administration in ruminants

The aim of this study was to establish the transfer of phenanthrene, pyrene, and benzo[a]pyrene and their major hydroxylated metabolites to milk and to urine after a single oral administration (100 mg per animal of each compound) in 4 lactating goats. Detection and identification of the analytes (native compounds, 1-OH pyrene, 3-OH phenanthrene, 3-OH benzo[a]pyrene) were achieved using gas chromatography-mass spectrometry. Benzo[a]pyrene, phenanthrene, and pyrene were rapidly detected in the plasma stream, whereas 1-OH pyrene and 3-OH phenanthrene appeared later in plasma. These data suggest that pyrene and phenanthrene are progressively metabolized within the organism. Recovery rates of pyrene and phenanthrene in milk over a 24-h period appeared to be very low (0.014 and 0.006%, respectively), whereas the transfer rates of their corresponding metabolites were significantly higher: 0.44% for 1-OH pyrene and 0.073% for 3-OH phenanthrene. Recovery rates in urine were found to be higher (1 to 10 times) than recovery rates in milk. The 1-OH pyrene was found to be the main metabolite in urine as well as in milk. Thus, as has been established for humans, 1-OH pyrene could be considered as a marker of ruminant exposure to polycyclic aromatic hydrocarbons. Because 1-OH pyrene and 3-OH phenanthrene were measured in milk (unlike their corresponding native molecules), metabolites of polycyclic aromatic hydrocarbons should be taken into consideration when evaluating the safety of milk. Benzo[a]pyrene and 3-OH benzo[a]pyrene were (less than 0.005%) transferred to milk and urine in very slight amounts. This very limited transfer rate of both compounds suggests a low risk of exposure by humans to benzo[a]pyrene or its major metabolite from milk or milk products.     

Emissions of parent, nitro, and oxygenated polycyclic aromatic hydrocarbons from residential wood combustion in rural china

Residential wood combustion is one of the important sources of air pollution in developing countries. Among the pollutants emitted, parent polycyclic aromatic hydrocarbons (pPAHs) and their derivatives, including nitrated and oxygenated PAHs (nPAHs and oPAHs), are of concern because of their mutagenic and carcinogenic effects. In order to evaluate their impacts on regional air quality and human health, emission inventories, based on realistic emission factors (EFs), are needed. In this study, the EFs of 28 pPAHs (EF(PAH28)), 9 nPAHs (EF(PAHn9)), and 4 oPAHs (EF(PAHo4)) were measured for residential combustion of 27 wood fuels in rural China. The measured EF(PAH28), EF(PAHn9), and EF(PAHo4) for brushwood were 86.7 ± 67.6, 3.22 ± 1.95 × 10(-2), and 5.56 ± 4.32 mg/kg, which were significantly higher than 12.7 ± 7.0, 8.27 ± 5.51 × 10(-3), and 1.19 ± 1.87 mg/kg for fuel wood combustion (p < 0.05). Sixteen U.S. EPA priority pPAHs contributed approximately 95% of the total of the 28 pPAHs measured. EFs of pPAHs, nPAHs, and oPAHs were positively correlated with one another. Measured EFs varied obviously depending on fuel properties and combustion conditions. The EFs of pPAHs, nPAHs, and oPAHs were significantly correlated with modified combustion efficiency and fuel moisture. Nitro-naphthalene and 9-fluorenone were the most abundant nPAHs and oPAHs identified. Both nPAHs and oPAHs showed relatively high tendencies to be present in the particulate phase than pPAHs due to their lower vapor pressures. The gas-particle partitioning of freshly emitted pPAHs, nPAHs, and oPAHs was primarily controlled by organic carbon absorption.     

Epigenetic toxicity of hydroxylated biphenyls and hydroxylated polychlorinated biphenyls on normal rat liver epithelial cells

2-Biphenylol, 3-biphenylol, 2,2'-biphenyldiol, 3,3'-biphenyldiol, 3-chloro-2-biphenylol, and 4,4'-dichloro-3-biphenylol were evaluated using the scrape-loading/dye transfer (SL/ DT) technique to determine in vitro gap junctional intercellular communication (GJIC) in a normal rat liver epithelial cell line as a measure of the epigenetic toxicity. Cytotoxicity was determined using the neutral red uptake assay. A dose range of 0-300 microM was examined. Only 3,3'-biphenyldiol and 4,4'-dichloro-3-biphenylol induced cytotoxicity within the tested dose ranges. Noncytotoxic doses were selected for evaluation of epigenetic toxicity. 4,4'-Dichloro-3-biphenylol was most inhibitory to GJIC at the lowest dose. The cytotoxicity and GJIC inhibitory effects observed for 4,4'-dichloro-3-biphenylol might be, although not exclusively, a consequence of the lipophilic nature of this chemical. 3-Chloro-2-biphenylol was least inhibitory to GJIC. 3-Chloro-2-biphenylol was less inhibitory to GJIC than 2-biphenylol because of the presence of the chlorine functional group, which appears to attenuate the toxic effect of the ortho-hydroxyl group. Although cells were capable of complete recovery of GJIC after removal of each of the chemicals, only with 2,2'-biphenyldiol and 4,4,'-dichloro-3-biphenylol did the cells demonstrate partial recovery without removal of the chemical. The more noncoplanar conformation of 2,2'-biphenyldiol and 2-biphenylol might explain their more inhibitory behavior in comparison to 3,3'-biphenyldiol and 3-biphenylol, respectively.     

羟基化大豆磷脂酰化改性的研究

以顺丁烯二酸酐为酰化试剂,对羟基化大豆磷脂进行酰化改性。考察了反应时间、反应温度和酰化试剂加入量对羟酰化改性大豆磷脂酰化率的影响。通过响应面优化实验,最终确定了羟基化大豆磷脂酰化改性的最佳工艺条件。结果表明,当反应时间为30 min、反应温度为55℃、顺丁烯二酸酐加入量为4%时,改性后大豆磷脂的酰化率为61.60%。采用红外图谱分析得出改性后的磷脂有酰胺基的生成,通过乳化稳定性实验得出羟酰化中和后磷脂的乳化稳定性有一定程度的提高。     

Chemistry and health effects of polymethoxyflavones and hydroxylated polymethoxyflavones

Polymethoxyflavones (PMFs) and hydroxylated polymethoxyflavones exist exclusively in citrus genus, especially in the citrus peels which have been used as herbal medicine for several diseases for thousands of years. In this review, the natural occurrence, isolation and separation of PMFs; synthetic scheme of hydroxylated PMF preparation, especially the reaction mechanism of preparation of 5-hydroxylated PMFs; biotransformation and metabolic fate of PMFs; the preliminary study on PMF bioavailability and the close relationship among solubility, permeability, absorption and oral bioavailability are summarized. The published bioactivity data on anti-inflammatory, anti-cancer and anti-atherogenic properties of PMFs have also been detailed along with a report of new findings of hydroxylated PMFs and their potent biological activities.     

Hexabromocyclododecane enantiomers: microsomal degradation and patterns of hydroxylated metabolites

The degradation of the enantiomers of α-, β-, and γ-hexabromocyclododecane (HBCD) by phase I metabolism was investigated using induced rat liver microsomes. HBCD isomers were quantified using HPLC-MS/MS (ESI(-)) after separation on a combination of a reversed phase and a chiral analytical column. The degradation of all six isomers followed first-order kinetics and the estimated half-lives ranged from 6.3 min for both β-HBCD enantiomers to 32.3 min in case of (+)-γ-HBCD. (+)-α- and (-)-γ-HBCD displayed significantly shorter half-lives than their corresponding antipodes. It could be shown that this degradation led to a significant enrichment of the first eluting enantiomers (-)-α- and (+)-γ-HBCD. Individual patterns of mono- and dihydroxylated derivatives obtained from each α- and γ-HBCD enantiomer were seen to be distinctly characteristic. The patterns of monohydroxylated HBCD derivatives detected in liver and muscle tissues of pollack, mackerel and in herring gull eggs were largely similar to those observed in the in vitro experiments with rat liver microsomes. This enabled individual hydroxy-HBCDs to be assigned to their respective parent HBCD enantiomers.     

Synthesis and antioxidant activity of hydroxylated phenanthrenes as cis-restricted resveratrol analogues

Five hydroxylated phenanthrenes as "cis-configuration-fixed" resveratrol analogues differing in the number and position of the hydroxyl groups were designed and synthesized. Their antioxidant activity was studied by ferric reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging, and DNA strand breakage-inhibiting assays, corresponding to their electron-donating, hydrogen-transfer and DNA-protecting abilities, respectively. In the above assays, their activity depends significantly on the number and position of the hydroxyl groups, and most of them are more effective than resveratrol. Noticeably, compound 9b (2,4,6-trihydroxyl phenanthrene) with the same hydroxyl group substitutions as resveratrol, is superior to the reference compound, highlighting the importance of extension of the conjugation over multiple aromatic-rings. Similar activity sequences were obtained in different experimental models, but the appreciable differences could contribute detailed insights into antioxidant mechanisms. Based on these results, the hydroxylated phenanthrenes may be considered as a novel type of resveratrol-directed antioxidants.     

Interconversion of hydroxylated and methoxylated polybrominated diphenyl ethers in Japanese medaka

Polybrominated diphenyl ethers (PBDEs), hydroxylated (OH) and methoxylated (MeO), have been widely detected in aquatic environments. However, relationships among these structurally related compounds in exposed organisms are unclear. To elucidate biotransformation relationships among BDE-47, 6-OH-BDE-47, and 6-MeO-BDE-47, dietary accumulation, maternal transfer, and tissue distribution of these compounds and their transformation products were investigated in sexually mature Japanese medaka (Oryzias latipes). In addition, transformation of each compound was determined in vitro using liver microsomes of medaka. OH-PBDEs and MeO-PBDEs were not detected in fish exposed to BDE-47. However, significant concentrations of 6-OH-BDE-47 were detected in medaka or microsomes exposed to 6-MeO-BDE-47. Significant concentrations of 6-MeO-BDE-47 were also measured in fish exposed to 6-OH-BDE-47, but 6-MeO-BDE-47 was not detected in microsomes exposed to 6-OH-BDE-47. Similar patterns of transformation products were observed in medaka eggs from adult fish during exposure. This study presents direct in vivo evidence of biotransformation of 6-MeO-BDE-47 to 6-OH-BDE-47. In addition, this is the ?rst study to demonstrate biotransformation of 6-OH-BDE-47 to 6-MeO-BDE-47. Demethylation of 6-MeO-BDE-47 was the primary transformation pathway leading to formation of 6-OH-BDE-47 in medaka, while the previously hypothesized formation of OH-PBDEs from synthetic BDE-47 did not occur. Biotransformation products formed in adult female medaka were transferred to eggs.     

Photochemical formation of polybrominated dibenzo-p-dioxins from environmentally abundant hydroxylated polybrominated diphenyl ethers

High levels of polybrominated dibenzo-p-dioxins (PBDDs) have been found in Baltic Sea biota, where the toxic load owing to, for example, polychlorinated dibenzo-p-dioxins and other organic pollutants is already high. The levels and geographic pattern of PBDDs suggest biogenic rather than anthropogenic origin, and both biotic and abiotic formation pathways have been proposed. Photochemical formation from hydroxylated polybrominated diphenyl ethers (OH-PBDE) is a proposed pathway for PBDDs in marine environments. Ultraviolet radiation-initiated transformations of OH-BDEs 47, 68, 85, 90, 99, and 123, which all are abundant in the environment, were investigated. It was shown that the most abundant PBDDs in the environment (1,3,7-triBDD and 1,3,8-triBDD) can be formed from the most abundant OH-BDEs (OH-BDE 47 and OH-BDE 68) at high rates and with percentage yields. In fact, most of the PBDDs that have been identified in the Baltic Sea environment were formed with high yield from the six studied OH-PBDE, through initial cyclization and subsequent debromination reactions. The high formation yields point to this route as an important source of PBDDs in biota. However, congeners showing relatively high retention in fish, specifically 1,3,6,8- and 1,3,7,9-tetraBDD, were not formed. These are likely formed by enzymatic coupling of brominated phenols.     

食品中多溴联苯醚及其羟基衍生物的研究进展

近年来,由于多溴联苯醚及其羟基衍生物具有毒性和污染持久性,它们的研究越来越受到重视。本文以食品中多溴联苯醚及其羟基衍生物为重点,对多溴联苯醚及其羟基衍生物的性质、主要来源、毒性、以及在食品中的污染水平和分析方法等进行了评述,为我国开展食品领域内多溴联苯醚及其羟基衍生物的限量制定和研究提供参考。     

新型香醋饮料的研制

结合传统香醋生产工艺，借鉴苗族民间保健醋酸饮料“黑密茶”的加工工艺和配方，以太谷大枣和糯米为发酵主料，配以银杏叶、甘草、生姜、枸杞等参与发酵，并采用根霉糖化、活性干酵母酒化和醋酸发酵，生产出具多种功能因子的新型醋酸饮料。     

Occurrences and fates of hydroxylated polybrominated diphenyl ethers in marine sediments in relation to trophodynamics

While occurrences and origins of hydroxylated (OH-) polybrominated diphenyl ethers (PBDEs) in organisms have been reported, the fates of these compounds in abiotic matrixes and related trophodynamics are unclear. The present study measured concentrations of nine OH-PBDEs, twelve methoxylated (MeO-) PBDEs, and eleven PBDEs in marine sediments and explored the trophodynamics of OH-PBDEs in five invertebrates, eight fish, and two species of birds from Liaodong Bay, north China. While concentrations of PBDEs were less than the limit of quantification in sediments, concentrations of ΣOH-PBDEs and ΣMeO-PBDEs were 3.2-116 pg/g dry weight (dw) and 3.8-56 pg/g dw, respectively. When the detected compounds were incubated in native marine sediments the interconversion between 6-OH-BDE47 and 6-MeO-BDE47 was observed. This result is consistent with the similar spatial distributions and significant correlation between the concentrations of these naturally occurring compounds. 6-OH-BDE47 and 2'-OH-BDE68 were detected as the two major congeners in organisms collected from Liaodong Bay, and concentrations were 0.24 ± 0.005 ng/g lw (lipid weight) and 0.088 ± 0.006 ng/g lw, respectively. Biota-sediment accumulation factors (BSAFs) for invertebrates of 6-OH-BDE47 and 2'-OH-BDE68 were 0.017-0.96 and 0.19-1.5 (except for short-necked clam: 6.3), respectively. Lipid-normalized concentrations of 6-OH-BDE47 and 2'-OH-BDE68 decreased significantly with trophic level with TMFs of 0.21 and 0.15, respectively. The fates of OH-PBDEs in sediment together with their trophodynamics in marine food webs suggested that OH-PBDEs are partitioned into sediment and undergo biodilution in the marine food web.     

Apoptosis-inducing activity of hydroxylated polymethoxyflavones and polymethoxyflavones from orange peel in human breast cancer cells

Sweet orange (Citrus sinensis L.) peel is a rich resource of flavonoids, especially polymethoxyflavones (PMFs). Citrus flavonoids exert a broad spectrum of biological activity, including antiproliferative and proapoptotic effects in cancer cells. We have recently shown that individual PMFs from orange peel induce Ca(2+)-mediated apoptosis in human breast cancer cells and that hydroxylation of PMFs is critical for enhancing their proapoptotic activity. Here, we report that the fraction of orange peel extract containing a mixture of non-hydroxylated PMFs (75.1%) and hydroxylated PMFs (5.44%) and the fraction containing only hydroxylated PMFs (97.2%) induce apoptosis in those cells as well. Treatment of MCF-7 breast cancer cells with these fractions inhibited growth and induced apoptosis associated with an increase in the basal level of intracellular Ca(2+). Effective concentrations of the hydroxylated PMFs fraction in inhibiting growth, inducing apoptosis, and increasing intracellular Ca(2+) were lower than those of the non-hydroxylated PMFs fraction. Our results strongly imply that bioactive PMFs from orange peel exert proapoptotic activity in human breast cancer cells, which depends on their ability to induce an increase in intracellular Ca(2+ )and thus, activate Ca(2+)-dependent apoptotic proteases.     

Characterization of aromatic compounds and biological activities of essential oils from Tunisian aromatic plants

The aromatic compounds and biological activities of essential oils from six Tunisian aromatic plants including Artemisia herba-alba, Rosmarinus officinalis, Thymus capitatus, Mentha piperita, Ocimum basilicum and Artemisia absinthium were investigated. Hydro-distillation was used to extract essential oil from these plants. The identification of compounds from essential oils was performed using GC–MS analysis. Camphor (28.47%) was the major compound of A. absinthium essential oil. High contents of verbenone (20.99%) and camphor (19.72%) were found in R. officinalis. In the case of T. capitatus, carvacrol (81.09%), gamma terpinene (6.61%) and caryophyllene (4.87%) were identified as the major compounds. While eugenol (24.69%), linalool (18.00%) were characteristic compounds of O. basilicum essential oil, camphor (39.10%) and farnesol (14.25%) together with bornyl acetate (12.31%) were the main constituents of A. absinthium. These oils were also subjected to a screening for their antioxidant activity and essential oil from A. absinthium showed a greater antioxidant activity (IC₅₀?=?0.0063 mg/mL) compared to the standard Vitamin E (IC₅₀?=?0.019 mg/mL). The antibacterial activities of the oils against seven pathogenic strains, Pseudomonas aeruginosa, Bacillus cereus, Salmonella, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis and Micrococcus luteus, were tested. The highest and broadest activity was shown by M. piperita; however, Ocimum basilicum was inactive against all strains. Essential oils were also evaluated for antidiabetic and anti-acetylcholinesterase activities. The IC₅₀ values of A. herba-alba and O. basilicum against α-amylase were respectively 17.76 and 16.32 µg/mL suggesting a powerful anti-diabetic effect comparable to that of acarbose (IC₅₀?=?14.88 µg/mL). R. officinalis, M. piperita and A. absinthium exhibited an interesting acetylcholinesterase inhibition with IC₅₀ equal to 22, 24 and 58 µg/mL respectively.