Highly sensitive and selective determination of 9,10-phenanthrenequinone in airborne particulates using high-performance liquid chromatography with pre-column derivatization and fluorescence detection

A water-soluble Pd4 molecular tweezer for selective encapsulation of isomeric quinones and their recyclable extraction

Quinones (QN) are one of the main components of diesel exhaust particulates that have significant detrimental effects on human health. Their extraction and purification have been challenging tasks because these atmospheric particulates exist as complex matrices consisting of inorganic and organic compounds. In this report, we introduce a new water soluble Pd4L2 molecular architecture (MT) with an unusual tweezer-shaped structure obtained by self-assembly of a newly designed phenothiazine-based tetra-imidazole donor (L) with the acceptor cis-[(tmeda)Pd(NO3)2] (M) [ tmeda = N,N,N',N'-tetramethylethane-1,2-diamine]. The molecular tweezer encapsulates some quinones existing in diesel exhaust particulates (DEPs) leading to the formation of host-guest complexes in 1 : 1 molar ratio. Moreover, MT binds phenanthrenequinone (PQ) more strongly than its isomer anthraquinone (AQ), an aspect that enables extraction of PQ with a purity of 91% from an equimolar mixture of the two isomers. Therefore, MT represents an excellent example of supramolecular receptor capable of selective aqueous extraction of PQ from PQ/AQ with many cycles of reusability.

Synthesis of 5-(4-(1H-phenanthro[9,10-d]imidazol-2-yl)benzylidene)thiazolidine-2,4-dione as promising DNA and serum albumin-binding agents and evaluation of antitumor activity

A series of phenanthro[9,10-d]imidazole/oxazole and acenaphtho[1,2-d]imidazole with different aryl groups at C2-position has been synthesized. These compounds were in vitro evaluated for antitumor activity against a panel of 60 human cancer cell lines. Compound 8 exhibits higher cytotoxicity towards leukemia, colon, melanoma, renal, and breast cancer cell lines than the other evaluated cell panels and low toxicity against normal cell line Hek293. The binding properties of compound 8 with DNA have been investigated with absorption, emission and circular dichroism as well as thermal denaturation experiments which indicate intercalation with base pairs of human and calf thymus DNA. The molecular docking and site-selective binding studies also reveal the predominant intercalation of compound 8 in base pairs of DNA. The interaction between thiazolidine based phenanthrene 8 and serum albumins (HSA and BSA), transport proteins, has also been explored which shows quenching of fluorescence through static mechanism. The thermodynamic parameters, obtained from van't Hoff relationship indicate the prevalence of hydrogen-bonding/hydrophobic interactions for the binding phenomenon.

Cytotoxicity of Air Pollutant 9,10-Phenanthrenequinone: Role of Reactive Oxygen Species and Redox Signaling

Atmospheric pollution has been a principal topic recently in the scientific and political community due to its role and impact on human and ecological health. 9,10-phenanthrenequinone (9,10-PQ) is a quinone molecule found in air pollution abundantly in the diesel exhaust particles (DEP). This compound has studied extensively and has been shown to develop cytotoxic effects both in vitro and in vivo. 9, 10-PQ has been proposed to play a critical role in the development of cytotoxicity via generation of reactive oxygen species (ROS) through redox cycling. This compound also reduces expression of glutathione (GSH), which is critical in Phase II detoxification reactions. Understanding the underlying cellular mechanisms involved in cytotoxicity can allow for the development of therapeutics designed to target specific molecules significantly involved in the 9,10-PQ-induced ROS toxicity. This review highlights the developments in the understanding of the cytotoxic effects of 9, 10-PQ with special emphasis on the possible mechanisms involved.

Determination of Tanshinones in Danshen (Salvia miltiorrhiza) by High-Performance Liquid Chromatography with Fluorescence Detection after pre-Column Derivatisation

INTRODUCTION

Tanshinones are a major class of bioactive ingredients in the traditional herbal medicines, Danshen (Salvia miltiorrhiza). A sensitive and reliable determination method for tanshinones is useful to ensure the quality of Danshen.

OBJECTIVE

To develop a sensitive and selective analytical method for tanshinones by high-performance liquid chromatography (HPLC) with fluorescence detection after pre-column derivatisation.

METHODOLOGY

The proposed method depends on derivatisation reaction of tanshinones with 4-carbomethoxybenzaldehyde and ammonium acetate forming intensely fluorescent imidazole derivative.

RESULTS

The proposed method provided excellent sensitivity with the detection limits of 3.3 nM (66 fmol/injection), 3.2 nM (64 fmol/injection) and 2.0 nM (40 fmol/injection) for cryptotanshinone, tanshinone I and tanshinone IIA, respectively, without the necessity of complicated instrumentations. The developed method is successfully applied to quantify the contents of tanshinones in Danshen.

CONCLUSION

The developed method is the first analytical method for tanshinones by fluorescence detection. Since the derivatisation reaction is selective for the o-quinone structure of tanshinone, the developed method will become a suitable mean for the discovering of tanshinone type diterpenoids from herbal samples. Copyright © 2017 John Wiley & Sons, Ltd.

Comparison of the effectiveness of soil heating prior or during in situ chemical oxidation (ISCO) of aged PAH-contaminated soils

Thermal treatments prior or during chemical oxidation of aged polycyclic aromatic hydrocarbon (PAH)-contaminated soils have already shown their ability to increase oxidation effectiveness. However, they were never compared on the same soil. Furthermore, oxygenated polycyclic aromatic hydrocarbons (O-PACs), by-products of PAH oxidation which may be more toxic and mobile than the parent PAHs, were very little monitored. In this study, two aged PAH-contaminated soils were heated prior (60 or 90 °C under Ar for 1 week) or during oxidation (60 °C for 1 week) with permanganate and persulfate, and 11 O-PACs were monitored in addition to the 16 US Environmental Protection Agency (US EPA) PAHs. Oxidant doses were based on the stoichiometric oxidant demand of the extractable organic fraction of soils by using organic solvents, which is more representative of the actual contamination than only the 16 US EPA PAHs. Higher temperatures actually resulted in more pollutant degradation. Two treatments were about three times more effective than the others: soil heating to 60 °C during persulfate oxidation and soil preheating to 90 °C followed by permanganate oxidation. The results of this study showed that persulfate effectiveness was largely due to its thermal activation, whereas permanganate was more sensitive to PAH availability than persulfate. The technical feasibility of these two treatments will soon be field-tested in the unsaturated zone of one of the studied aged PAH-contaminated soils.

Reactive paper spray mass spectrometry for in situ identification of quinones

RATIONALE

The polycyclic aromatic hydrocarbons quinones are reported to be harmful and could cause mutations and cancer via the generation of reactive oxygen species through their redox cycle in human body. For detection by gas chromatography and high-performance liquid chromatography mass spectrometry (MS), sample pretreatments and chromatographic separation prior to MS are generally required, which makes the whole analytical process laborious and time-consuming, resulting in difficulties for fast screening targets from complicated matrices. Thus facile, rapid and reliable MS methods for detection of quinones in complicated matrices are in great demand.

METHODS

Reactive paper spray mass spectrometry is reported for rapid identification and quantification of quinones in complicated matrices. The method is based on an in situ derivatization reaction between cysteamine and quinones prior to analysis with paper spray mass spectrometry. With the addition of an easily charged chemical tag, the ionization efficiency of analysts is greatly improved. Due to the high ionization efficiency of the drivatives, quinones in complicated matrices could be detected rapidly without any pretreatment.

RESULTS

Under the optimized experimental conditions, the linear dynamic ranges for both 1,4-benzoquinone and 1,4-naphthoquinone are 0.4-40 ng and that for 1,4-anthraquinone is 0.4-20 ng. Limits of detection for these three analytes were measured to be 160, 40 and 200 pg using methyl-p-benzoquinone as internal standard. The capability to conduct MS analysis under ambient pressure is illustrated by identification of 1,4-naphthoquinone and 1,4-anthraquinone in raw urine, raw serum and cell culture medium.

CONCLUSIONS

Reactive paper spray could be applied to fast screening of quinones from complicated matrices. Therefore, we believe that reactive paper spray mass spectrometry might be potentially useful in the fields of environmental sciences, metabolomics and clinic analysis.

An oxygenated metabolite of benzo[a]pyrene increases hepatic β-oxidation of fatty acids in chick embryos

Polycyclic aromatic hydrocarbons (PAHs) are well-known carcinogens to humans and ecotoxicological effects have been shown in several studies. However, PAHs can also be oxidized into more water soluble-oxygenated metabolites (Oxy-PAHs). The first purpose of the present project was to (1) assess the effects of a mixture containing three parent PAHs: anthracene, benz[a]anthracene, and benzo[a]pyrene versus a mixture of their oxygenated metabolites, namely: anthracene-9,10-dione, benz[a]anthracene-7,12-dione, and 9,10-dihydrobenzo[a]pyrene-7-(8H)-one on the hepatic fatty acid β-oxidation in chicken embryos (Gallus gallus domesticus) exposed in ovo. The second and also main purpose of the project was to (2) assess the effects of the parent PAHs versus their oxy-PAHs analogues when injected individually, followed by (3) additional testing of the individual oxy-PAHs. The hepatic β-oxidation was measured using a tritium release assay with [9,10-(3)H]-palmitic acid (16:0) as substrate. The result from the first part (1) showed reduced hepatic β-oxidation after exposure in ovo to a mixture of three PAHs, however, increased after exposure to the mixture of three oxy-PAHs compared to control. The result from the second part (2) and also the follow-up experiment (3) showed that 9,10-dihydrobenzo[a]pyrene-7-(8H)-one was the causative oxy-PAH. The implication of this finding on the risk assessment of PAH metabolite exposure in avian wildlife remains to be determined. To the best of our knowledge, no similar studies have been reported.

[Development of selective determination methods for quinones with fluorescence and chemiluminescence detection and their application to environmental and biological samples]

Quinones are compounds that have various characteristics such as a biological electron transporter, an industrial product and a harmful environmental pollutant. Therefore, an effective determination method for quinones is required in many fields. This review describes the development of sensitive and selective determination methods for quinones based on some detection principles and their application to analyses in environmental, pharmaceutical and biological samples. Firstly, a fluorescence method was developed based on fluorogenic derivatization of quinones and applied to environmental analysis. Secondly, a luminol chemiluminescence method was developed based on generation of reactive oxygen species through the redox cycle of quinone and applied to pharmaceutical analysis. Thirdly, a photo-induced chemiluminescence method was developed based on formation of reactive oxygen species and fluorophore or chemiluminescence enhancer by the photoreaction of quinones and applied to biological and environmental analyses.

Determination of 9, 10-phenanthrenequinone in airborne particulates by High-Performance Liquid Chromatography with post-column fluorescence derivatization using 2-aminothiophenol

9, 10-Phenanthrenequinone (PQ) is regarded as a harmful environmental pollutant and its presence has been reported in atmospheric environment. The measurement of PQ in environment should be necessary to evaluate the influence of PQ on human health. We found that PQ reacted with 2-aminothiophenol under acidic condition to form fluorescent derivative which emits green fluorescence at 510nm. Based on this reaction, a simple and rapid determination method for PQ was developed by HPLC with post-column derivatization and fluorescence detection. By the proposed HPLC system, PQ was detected at 24min and the detection limit was 67fmol/injection (S/N=3). The proposed method was able to determine the atmospheric PQ concentrations by the direct injection of extract from airborne particulates.

Determination of long-chain fatty acids in bryophyte plants extracts by HPLC with fluorescence detection and identification with MS

A sensitive method for the determination of long-chain fatty acids (LCFAs) (>C20) using 1-[2-(p-toluenesulfonate)-ethyl]-2-phenylimidazole-[4,5-f]-9,10-phenanthrene (TSPP) as tagging reagent with fluorescence detection and identification with post-column APCI/MS has been developed. The LCFAs in bryophyte plant samples were obtained based on distillation extraction with 1:1 (v/v) chloroform/methanol as extracting solvent. TSPP could easily and quickly label LCFAs at 90 degrees C in the presence of K2CO3 catalyst in DMF. Eleven free LCFAs from the extracts of bryophyte plants were sensitively determined. Maximal labeling yields close to 100% were observed with a five-fold excess of molar reagent. Separation of the derivatized fatty acids exhibited a good baseline resolution in combination with a gradient elution on a reversed-phase Eclipse XDB-C8 column. Calculated detection limits from 1.0 pmol injection, at a signal-to-noise ratio of 3, were 26.19-76.67 fmol. Excellent linear responses were observed with coefficients of >0.9996. Good compositional data were obtained from the analysis of the extracted LCFAs containing as little as 0.2g of bryophyte plant samples. Therefore, the facile TSPP derivatization coupled with HPLC/APCI/MS analysis allowed the development of a highly sensitive method for the quantitation of trace levels of LCFAs from biological and natural environmental samples.

Concentration and trend of 9,10-phenanthrenequinone in airborne particulates collected in Nagasaki city, Japan

9,10-Phenanthrenequinone (PQ), one of the components of atmospheric pollutants, has potent harmful effects on human health. PQ in airborne particulates collected in Nagasaki city was determined by HPLC with fluorescence derivatization. PQ extracted from airborne particulates using methanol was derivatized with benzaldehyde in the presence of ammonium acetate to give a fluorescent compound. The average concentration (mean+/-SD, n=52) of PQ found in airborne particulates collected from July 1997 to June 1998 was 0.287+/-0.128 ng m-3. Concentrations of PQ in winter were higher than those in summer. In a weekly variation study, PQ concentrations were higher during weekdays and lower at weekend. The levels of PQ were obviously correlated with those of phenanthrene (PH) that is considered as a parent compound of PQ. This observation suggested that PQ was emitted into the atmosphere from the same source as PH, or PQ was converted from PH in the atmosphere.