ABSTRACT
Over the last decade, human activities in the industrial and agricultural sectors have significantly increased the concentration of persistent and harmful pollutants in aquatic ecosystems. The use of microorganisms is a green strategy for the bio-removal of certain contaminants. However, other pollutants in the same ecosystems can reduce their degrading activity and even affect their survival. Therefore, this study aimed to evaluate the efficiency of benzo(b)fluoranthene (BbF) and benzo(k)fluoranthene (BkF) removal by Selenastrum capricornutum in the presence of triazine herbicides, compounds mainly used in broadleaf weeds. The interest of this work focused on identifying in which of the microalgal components the degrading activity is best evidenced and affected. For this purpose, the use of solid-phase extraction (SPE) and matrix solid-phase dispersion (MSPD) extraction procedures and HPLC-UV analysis allowed the BbF and BkF trace quantification in biomass, liquid medium, and cell lysate separately from cultures exposed to these polycyclic aromatic hydrocarbons (PAHs) alone or with herbicides. The recovery percentages were between 78 and 94 %, good linearity (r2 ≈ 0.99), precision values measured as RSD < 15 %, and limits of detection (LOQs) at levels of ng mL-1 and ng mg-1 were obtained. The individual PAH amounts measured in the components of microalgae cultures show similar removal kinetics (removal percentages: 82-89 %). Likewise, the analysis demonstrated that the removal of PAHs is not affected in the presence of triazine herbicides (atrazine and cyanazine) and with similar removal percentages (79-86 %) compared to those cultures exposed to individual PAHs (74-83 %). These results support the possible real-world applications of PAH removal by extracts from S. capricornutum in aquatic environments contaminated with PAHs and near agriculture areas where triazine herbicides are used.
Subject(s)
Fluorenes , Herbicides , Microalgae , Solid Phase Extraction , Triazines , Solid Phase Extraction/methods , Chromatography, High Pressure Liquid/methods , Herbicides/analysis , Herbicides/isolation & purification , Triazines/analysis , Triazines/isolation & purification , Microalgae/chemistry , Microalgae/metabolism , Fluorenes/analysis , Fluorenes/chemistry , Fluorenes/isolation & purification , Water Pollutants, Chemical/analysis , Biodegradation, EnvironmentalABSTRACT
Eight new decahydrofluorene-class alkaloids, microascones A and B (1 and 2), 2,3-epoxyphomapyrrolidone C (3), 14,16-epiascomylactam B (4), 24-hydroxyphomapyrrolidone A (5), and microascones C-E (6-8), along with five known analogs (9-13) were isolated from the marine-derived fungus Microascus sp. SCSIO 41821. Compounds 1 and 2 have an unprecedented complex macrocyclic alkaloid skeleton with a 6/5/6/5/6/5/13 polycyclic system. Their structures and absolute configurations were determined by spectroscopic analysis, quantum chemical calculations of ECD spectra, and 13C NMR chemical shifts. Compounds 10-13 showed selective enzyme inhibitory activity against PTPSig, PTP1B, and CDC25B, and 4, 9, and 10 exhibited strong antibacterial activity against seven tested pathogens. Their structure-bioactivity relationship was discussed, and a plausible biosynthetic pathway for 1-8 was also proposed.
Subject(s)
Alkaloids , Anti-Bacterial Agents , Microbial Sensitivity Tests , Alkaloids/pharmacology , Alkaloids/chemistry , Alkaloids/isolation & purification , Molecular Structure , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Structure-Activity Relationship , Marine Biology , Ascomycota/chemistry , Fluorenes/pharmacology , Fluorenes/chemistry , Fluorenes/isolation & purification , Protein Tyrosine Phosphatase, Non-Receptor Type 1/antagonists & inhibitorsABSTRACT
Two new compounds, dihydrodengibsinin (1) and dendrogibsol (2), were isolated from the whole plant of Dendrobium gibsonii, together with seven known compounds (3-9). The structures of the new compounds were elucidated by their spectroscopic data. All these isolates were evaluated for their α-glucosidase inhibitory activities. Dendrogibsol (2) and lusianthridin (7) showed strong α-glucosidase inhibitory activity when compared with acarbose. An enzyme kinetic study revealed that dendrogibsol (2) is a noncompetitive inhibitor of α-glucosidase.
Subject(s)
Dendrobium/chemistry , Fluorenes/isolation & purification , Glycoside Hydrolase Inhibitors/isolation & purification , Plant Extracts/isolation & purification , alpha-Glucosidases/metabolism , Fluorenes/metabolism , Glucans/chemistry , Glycoside Hydrolase Inhibitors/metabolism , Molecular Structure , Phenanthrenes/isolation & purification , Phenanthrenes/metabolism , Plant Extracts/metabolism , Solvents/chemistryABSTRACT
In this study, 31 racemates of Nα-FMOC (fluorenylmethoxycarbonyl) amino acids (AAs) with different chemico-physical characteristics (neutral nonpolar, neutral polar, acidic and basic) have been successfully resolved in fast enantioselective chromatography on recently-developed zwitterionic-teicoplanin chiral stationary phases (CSPs). The CSPs were prepared by covalently bonding the teicoplanin selector on fully-porous particles of narrow dispersion particle-size distribution (particle diameter 1.9 µm) and superficially-porous particles (2.0 µm). Both the zwitterionic-teicoplanin CSPs have proved to be ideal media for the separation of this important class of compounds. In particular, the zwitterionic CSP prepared on superficially-porous particles exhibited superior enantioselectivity and resolution, compared to that made of fully porous particles, in virtue of more favorable thermodynamics. The zwitterionic nature of these CSPs allowed avoiding the annoying effect of Donnan's exclusion of enantiomers from the stationary phase. This effect, on the opposite, was frequently observed on a commercial teicoplanin CSP (Teicoshell) employed for comparative purposes. Noticeably, on the zwitterionic-teicoplanin CSPs, by using either acetonitrile- or methanol-rich mobile phases (MPs), it was possible to favor speed over enantioresolution and vice versa. This work gives further replies to the request for rapid determination of enantiomeric excess of Nα-FMOC proteinogenic (and non-proteinogenic) AAs, typically used as preferred chiral synthons in the solid-phase synthesis of therapeutic peptides.
Subject(s)
Amino Acids/isolation & purification , Chromatography/methods , Fluorenes/isolation & purification , Proteins/chemistry , Teicoplanin/chemistry , Porosity , StereoisomerismABSTRACT
A polyaniline composite doped with etched multi-walled carbon nanotubes and UiO-66-NH2 was prepared by electropolymerization. It was used as a sorbent to extract the polycyclic aromatic hydrocarbons (PAHs) phenanthrene, fluoranthene and pyrene. Its surface morphology, crystal structure and capability of adsorbing PAHs were characterized by scanning electron microscopy, X-ray photoelectron spectrometry, Fourier transform infrared spectrometry and zeta potentiometry. The π stacking and anion-π interactions are shown to play dominant roles in the sorption mechanism. Coupled with high performance liquid chromatography, the composite-modified fiber was applied to detect PAHs in lake water samples by direct immersion extraction. The method excels by (a) wide linear range (0.05-20 ng mL-1), (b) low limits of detection (10 pg mL-1), (c) satisfactory recovery from spiked samples (84.7-113.8%), and (d) good reproducibility (relative standard deviations of <6.5%). The method is superior in terms of costs and reproducibility compared to some pretreatment methods with mass spectrometric detection. Graphical abstractSchematic representation for interaction between PANI-etched MWCNT/UiO-66-NH2 and polycyclic aromatic hydrocarbons (phenanthrene, fluoranthene, pyrene).
Subject(s)
Chromatography, High Pressure Liquid/methods , Nanocomposites/chemistry , Polycyclic Aromatic Hydrocarbons/isolation & purification , Water Pollutants/isolation & purification , Adsorption , Aniline Compounds/chemistry , Chromatography, High Pressure Liquid/standards , Fluorenes/isolation & purification , Lakes/chemistry , Limit of Detection , Metal-Organic Frameworks/chemistry , Nanotubes, Carbon/chemistry , Phenanthrenes/isolation & purification , Pyrenes/isolation & purification , Reproducibility of ResultsABSTRACT
Roasting is an important process in cocoa production which may lead to formation of non-desirable compounds such as polycyclic aromatic hydrocarbons (PAHs). Therefore, PAH4 (sum of four different polycyclic aromatic hydrocarbons; benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) in roasted cocoa beans was determined using a modified method (combination of QuEChERS and DLLME), and quantified by HPLC-FLD. The modified method was validated and met the performance criteria required by the EU Regulation (No. 836/2011). Results show a significant (pâ¯<â¯0.05) increase of PAH4 (0.19-7.73â¯ng/g) with an increase in temperatures (110-190⯰C) and duration (10-50â¯min). The PAHs content in whole cocoa bean roasting was detected even at the lowest temperature (110⯰C) compared to nib roasting detected at 150⯰C which indicates that PAHs was transferred from dried shells to roasted cocoa beans during the roasting process. The data obtained may help to control and minimize PAH4 formation during cocoa processing.
Subject(s)
Cacao/chemistry , Chromatography, High Pressure Liquid/methods , Liquid Phase Microextraction/methods , Polycyclic Aromatic Hydrocarbons/analysis , Polycyclic Aromatic Hydrocarbons/isolation & purification , Anthracenes/analysis , Anthracenes/isolation & purification , Benzo(a)pyrene/analysis , Benzo(a)pyrene/isolation & purification , Chrysenes/analysis , Chrysenes/isolation & purification , Fluorenes/analysis , Fluorenes/isolation & purification , Seeds/chemistryABSTRACT
Insulin plays a key role in glucose homeostasis and is hence used to treat hyperglycemia, the main characteristic of diabetes mellitus. Annulohypoxylon annulatum is an inedible ball-shaped wood-rotting fungus, and hypoxylon F is one of the major compounds of A. annulatum. The aim of this study is to evaluate the effects of hypoxylonol F isolated from A. annulatum on insulin secretion in INS-1 pancreatic ß-cells and demonstrate the molecular mechanisms involved. Glucose-stimulated insulin secretion (GSIS) values were evaluated using a rat insulin ELISA kit. Moreover, the expression of proteins related to pancreatic ß-cell metabolism and insulin secretion was evaluated using Western blotting. Hypoxylonol F isolated from A. annulatum was found to significantly enhance glucose-stimulated insulin secretion without inducing cytotoxicity. Additionally, hypoxylonol F enhanced insulin receptor substrate-2 (IRS-2) levels and activated the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway. Interestingly, it also modulated the expression of peroxisome proliferator-activated receptor γ (PPARγ) and pancreatic and duodenal homeobox 1 (PDX-1). Our findings showed that A. annulatum and its bioactive compounds are capable of improving insulin secretion by pancreatic ß-cells. This suggests that A. annulatum can be used as a therapeutic agent to treat diabetes.
Subject(s)
Ascomycota/chemistry , Fluorenes/pharmacology , Insulin Secretion/drug effects , Insulin-Secreting Cells/drug effects , Insulin-Secreting Cells/metabolism , Animals , Cell Line , Fluorenes/isolation & purification , Gene Expression Regulation/drug effects , Homeodomain Proteins/metabolism , Insulin Receptor Substrate Proteins/metabolism , PPAR gamma/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Rats , Signal Transduction/drug effects , Trans-Activators/metabolismABSTRACT
An environmentally benign and cost-effective method was designed for isolating and purifying condensed arenes from acetone-extractable portion (AEP) of a high-temperature coal tar through a high pressure preparative chromatograph (HPPC) with different packings, including silica gel, octadecyl silane, octyl bonded silica gel, and diol bonded silica gel. In total, 196 compounds were detected with a gas chromatograph/mass spectrometer from AEP and its eluates. From the eluates, naphthalene, anthracene, phenanthrene, fluoranthene, and pyrene were successfully isolated and purified, and their structures were confirmed by their 1H and 13C nuclear magnetic resonance spectra in addition to their mass spectra. Extraction-HPPC device and solvent recovery process were designed and developed, which can potentially be applied to industrial production because the process is easy-to-operate and ecofriendliness. In addition, the solvents used can be easily recovered and reused, and neither waste water nor other pollutions are emitted.
Subject(s)
Coal Tar/chemistry , Gas Chromatography-Mass Spectrometry/methods , Hot Temperature , Polycyclic Aromatic Hydrocarbons/isolation & purification , Pressure , Anthracenes/isolation & purification , Fluorenes/isolation & purification , Naphthalenes/isolation & purification , Phenanthrenes/isolation & purification , Pyrenes/isolation & purificationABSTRACT
We evaluated the protective effects of hypoxylonol C and 4,5,4',5'-tetrahydroxy-1,1'-binaphthyl (BNT) isolated from Annulohypoxylon annulatum on pancreatic ß-cell apoptosis, using the ß-cell toxin streptozotocin (STZ). Hypoxylonol C and BNT restored the STZ-induced decrease in INS-1 cell viability in a dose-dependent manner. In addition, treatment of INS-1 cells with 50⯵M STZ resulted in an increase in apoptotic cell death, which was observed as annexin V fluorescence intensity. Apoptotic cell death was decreased by co-treatment with 100⯵M hypoxylonol C and 100⯵M BNT. Similarly, STZ caused a marked increase in the expression of cleaved caspase-8, caspase-3, Bax, and poly (ADP-ribose) polymerase (PARP), as well as a decrease in the expression of B-cell lymphoma 2 (Bcl-2), which was reversed by co-treatment with 100⯵M hypoxylonol C and 100⯵M BNT. These findings suggest that hypoxylonol C and BNT play an important role in protecting pancreatic ß-cells against apoptotic damage.
Subject(s)
Fluorenes/pharmacology , Naphthols/pharmacology , Protective Agents/pharmacology , Streptozocin/toxicity , Animals , Apoptosis/drug effects , Ascomycota/chemistry , Caspase 3/metabolism , Caspase 8/metabolism , Cell Line, Tumor , Fluorenes/isolation & purification , Insulin-Secreting Cells/drug effects , Naphthols/isolation & purification , Oxidative Stress/drug effects , Poly(ADP-ribose) Polymerases/metabolism , Protective Agents/isolation & purification , Proto-Oncogene Proteins c-bcl-2/metabolism , Rats , Reactive Oxygen Species/metabolism , bcl-2-Associated X Protein/metabolismABSTRACT
Diazobenzofluorene-containing atypical angucyclines exhibit promising biological activities. Here we report the inactivation of an amidotransferase-encoding gene flsN3 in Micromonospora rosaria SCSIO N160, a producer of fluostatins. Bioinformatics analysis indicated that FlsN3 was involved in the diazo formation. Chemical investigation of the flsN3-inactivation mutant resulted in the isolation of a variety of angucycline aromatic polyketides, including four racemic aminobenzo[b]fluorenes stealthins Dâ»G (9â»12) harboring a stealthin C-like core skeleton with an acetone or butanone-like side chain. Their structures were elucidated on the basis of nuclear magnetic resonance (NMR) spectroscopic data and X-ray diffraction analysis. A plausible mechanism for the formation of stealthins Dâ»G (9â»12) was proposed. These results suggested a functional role of FlsN3 in the formation/modification of Nâ»N bond-containing fluostatins.
Subject(s)
Aquatic Organisms/metabolism , Bacterial Proteins/metabolism , Fluorenes/isolation & purification , Micromonospora/metabolism , Transaminases/metabolism , Bacterial Proteins/genetics , Biosynthetic Pathways , Computational Biology , Crystallography, X-Ray , Fluorenes/chemistry , Fluorenes/metabolism , Heterocyclic Compounds, 4 or More Rings/chemistry , Magnetic Resonance Spectroscopy , Molecular Structure , Nitrogen/chemistry , Streptomyces , Transaminases/geneticsABSTRACT
A plunger assisted solvent extraction (PASE) method for multi-channel silicone rubber trap samplers was developed and evaluated as an alternative to direct thermal desorption for the monitoring of polycyclic aromatic hydrocarbons (PAHs). The proposed extraction method was simple, fast (a total of 2â¯min for extraction), and used a small volume of solvent (a total of 2â¯mL from two sequential 1â¯mL extractions). The PASE method presented an advantage over thermal desorption in that samples could be re-analyzed, as only a portion of the extract was injected. Additionally, this approach is cost effective and can be applied in laboratories which do not have thermal desorption systems, hence allowing for the more widespread use of the polydimethylsiloxane samplers which can be employed as denuders in the monitoring of gas and particle partitioning of air pollutants. The method was validated over a wide concentration range (0.005-10â¯ng µL-1) and the limits of detection ranged from 13.6â¯ngâ¯m-3 for naphthalene to 227.1â¯ngâ¯m-3 for indeno[1,2,3-cd]pyrene. Overall extraction efficiencies of the target PAHs were good (from 76% for naphthalene to 99% for phenanthrene) with relative standard deviations below 6%. The PASE method was successfully applied to the analysis of domestic fire air emission samples taken at 10 and 20â¯min after ignition, using a sampling flow rate of 500â¯mLâ¯min-1 for 10â¯min in each case. The samples were found to contain primarily naphthalene (maximum concentration of 9.5⯵gâ¯m-3, 10â¯min after ignition), as well as fluorene, anthracene, phenanthrene, fluoranthene and pyrene.
Subject(s)
Air Pollutants/analysis , Polycyclic Aromatic Hydrocarbons/analysis , Silicone Elastomers/chemistry , Solvents/chemistry , Air Pollutants/isolation & purification , Fluorenes/analysis , Fluorenes/isolation & purification , Gas Chromatography-Mass Spectrometry , Limit of Detection , Liquid-Liquid Extraction , Naphthalenes/analysis , Naphthalenes/isolation & purification , Phenanthrenes/analysis , Phenanthrenes/isolation & purification , Polycyclic Aromatic Hydrocarbons/isolation & purificationABSTRACT
Novel and sensitive electrochemical sensor was fabricated for the assay of anti-HCV ledipasvir (LEDV) in different matrices. The designed sensor was based on 3D spinel ferromagnetic NiFe2O4 nanospheres and reduced graphene oxide (RGO) supported by morpholinium acid sulphate (MHS), as an ionic liquid (RGO/NSNiFe2O4/MHS). This sensor design was assigned to synergistically tailor the unique properties of nanostructured ferrites, RGO, and ionic liquid to maximize the sensor response. Electrode modification prevented aggregation of NiFe2O4, increasing electroactive surface area and allowed remarkable electro-catalytic oxidation of LEDV with an enhanced oxidation response. Differential pulse voltammetry was used for detection LEDV in complex matrices whereas; cyclic voltammetry and other techniques were employed to characterize the developed sensor properties. All experimental factors regarding sensor fabrication and chemical sensing properties were carefully studied and optimized. Under the optimum conditions, the designated sensor displayed a wide linear range (0.4-350â¯ngâ¯mL-1) with LOD of 0.133â¯ngâ¯mL-1. Additionally, the proposed sensor demonstrated good selectivity, stability and reproducibility, enabling the quantitative detection of LEDV in Harvoni® tablets, human plasma and in a pharmacokinetic study. Our findings suggest that the developed sensor is a potential prototype material for fabrication of high-performance electrochemical sensors.
Subject(s)
Benzimidazoles/isolation & purification , Biosensing Techniques , Fluorenes/isolation & purification , Hepacivirus/drug effects , Hepatitis C/drug therapy , Benzimidazoles/blood , Benzimidazoles/chemistry , Benzimidazoles/therapeutic use , Catalysis , Dielectric Spectroscopy , Fluorenes/blood , Fluorenes/chemistry , Fluorenes/therapeutic use , Graphite/chemistry , Hepacivirus/pathogenicity , Hepatitis C/blood , Hepatitis C/virology , Humans , Ionic Liquids/chemistry , Limit of Detection , Nanospheres/chemistryABSTRACT
Polycyclic aromatic hydrocarbons (PAHs) are food-processing contaminants considered to be carcinogenic and genotoxic. Due to its drying process stage, teas may be contaminated with PAHs. The aim of the study was to validate an analytical method involving QuEChERS and HPLC-FLD for the determination of PAH4 in teas and evaluate the contamination levels in 10 different types of teas from Brazil. Recoveries varied from 54% to 99% and relative standard deviations from 1% to 21%. Limits of detection and quantification were from 0.03 to 0.3 µg/kg and 0.1 to 0.5 µg/kg, respectively. Mate tea presented the highest PAH levels, with PAH4 varying from 194 to 1795 µg/kg; followed by black (1.8-186 µg/kg), white (24-119 µg/kg), and green teas (3.1-92 µg/kg). Teas with lowest PAH4 were strawberry, lemongrass, peppermint, and boldo. Only trace levels of PAHs were detected in tea infusions, so apparently it would not affect PAH intake by Brazilian population.
Subject(s)
Carcinogens, Environmental/analysis , Food Contamination , Polycyclic Aromatic Hydrocarbons/analysis , Tea/chemistry , Teas, Herbal/analysis , Analytic Sample Preparation Methods , Benz(a)Anthracenes/analysis , Benz(a)Anthracenes/isolation & purification , Benzo(a)pyrene/analysis , Benzo(a)pyrene/isolation & purification , Brazil , Carcinogens, Environmental/isolation & purification , Chromatography, High Pressure Liquid , Chrysenes/analysis , Chrysenes/isolation & purification , Fluorenes/analysis , Fluorenes/isolation & purification , Food Handling , Food Inspection/methods , Ilex paraguariensis/chemistry , Limit of Detection , Oxidation-Reduction , Plant Leaves/chemistry , Polycyclic Aromatic Hydrocarbons/isolation & purification , Reproducibility of Results , Spectrometry, Fluorescence , Tea/economics , Teas, Herbal/economicsABSTRACT
To develop an efficient and environmental-friendly approach to detoxicate nickel (Ni) and fluoranthene co-contaminated soil, the combined application of Coprinus comatus (C. comatus) with Serratia sp. FFC5 and/or Enterobacter sp. E2 was investigated. The pot experiment tested the influences of bacterial inoculation on the growth of C. comatus, content of Ni in C. comatus, Ni speciation in soil, fluoranthene dissipation, soil enzymatic activities, bacterial population and community structure. With the inoculation of bacteria, the fresh weights of C. comatus, concentration of Ni in C. comatus and the dissipation rates of fluoranthene were increased by 17.73-29.38%, 68.97-204.97% and 34.84-60.90%, respectively. Notably, results illustrated that the co-inoculation of FFC5 and E2 showed better effect in biomass enhancement, Ni accumulation and fluoranthene dissipation than solitary inoculation. Simultaneously, higher soil enzymatic and microbiological activities suggested that the integrated detoxication method of bacteria and C. comatus could improve soil quality. Therefore, we can infer that bacterial inoculation strengthened detoxication effect of C. comatus in Ni-fluoranthene co-contaminated soil, indicating that the combined application of C. comatus and bacteria can be an efficient alternative for detoxicating Ni and fluoranthene co-contaminated soil.
Subject(s)
Biodegradation, Environmental , Coprinus , Fluorenes/isolation & purification , Nickel/isolation & purification , Soil Pollutants/isolation & purification , Bacteria , Soil , Soil MicrobiologyABSTRACT
The first synthesis of dendroflorin has been achieved in 10 steps with an overall yield of 5.5%. The key step in the synthesis features the biphenyl structure is built through Suzuki-Miyaura reaction. In addition, the ortho-localization effect induced by aromatic substituent during the bromination of intermediate 8 is also observed and discussed.
Subject(s)
Benzoates/chemical synthesis , Dendrobium/chemistry , Fluorenes/isolation & purification , Benzoates/chemistry , Biphenyl Compounds/chemistry , Catalysis , Fluorenes/chemistry , Hydroquinones/chemistry , Molecular StructureABSTRACT
The chiral separation of d- and l- FMOC amino acids was undertaken using the Lux Cellulose-1 polysaccharide based chiral column in HPLC (normal phase and reverse phase) and SFC conditions. This was done to compare the relative selectivity and separation between the three separation modes and to evaluate the potential benefits of SFC separations with regards to resolution, throughput, economic and environmental impact. It was established that the separation of d- and l- FMOC amino acids in SFC displayed behaviours that were similar to both normal phase and reversed phase, rather than distinctly one or the other. Additionally, although reversed phase conditions yielded significantly higher resolution values between enantiomers across the range of amino acids studied, improvements in selectivity in SFC via the introduction of higher concentrations of formic acid in the mobile phase allowed for better resolution per unit of time. Moreover since the SFC mobile phase is composed mostly of recyclable CO2, there is a reduction in organic solvent consumption, which minimises the economic and environmental costs.
Subject(s)
Amino Acids/chemistry , Amino Acids/isolation & purification , Chlorides/chemistry , Chromatography, High Pressure Liquid/methods , Chromatography, Supercritical Fluid/economics , Chromatography, Supercritical Fluid/methods , Fluorenes/chemistry , Carbon Dioxide/chemistry , Cellulose/chemistry , Chromatography, High Pressure Liquid/economics , Environment , Fluorenes/isolation & purification , Formates/chemistry , Solvents/chemistry , StereoisomerismABSTRACT
Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) are ubiquitous environmental pollutants attracting increasing attention because of their potent mutagenicity to humans. Previous studies of nitro-PAHs focused on investigating their formation mechanisms and detecting them in atmospheric environment; however, few studies have reported their occurrence in food samples, and regulations on nitro-PAHs are still lacking. We report in this study the development and application of a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for determination of nitro-PAHs in rice and vegetable samples. Analysis of the collected samples by the validated method revealed 1-nitropyrene and 2-nitrofluorene were widespread food contaminants. A comparative study with benzo[a]pyrene, the commonly used marker for PAH exposure, showed that carcinogenic nitro-PAHs existed in rice and vegetables at similar concentrations. Dietary exposure risk, which was estimated based on the surveillance data, suggested 3.28-5.03 ng/kg/day of nitro-PAHs exposure for Hong Kong citizens from rice grains and vegetables.
Subject(s)
Carcinogens/isolation & purification , Environmental Pollutants/isolation & purification , Fluorenes/isolation & purification , Oryza/chemistry , Pyrenes/isolation & purification , Vegetables/chemistry , Benzo(a)pyrene/analysis , Benzo(a)pyrene/isolation & purification , Carcinogens/analysis , Chromatography, High Pressure Liquid , Environmental Pollutants/analysis , Fluorenes/analysis , Food Contamination/analysis , Hong Kong , Pyrenes/analysis , Seeds/chemistryABSTRACT
A new validated bioanalytical method based on LC tandem MS has been developed for the simultaneous extraction and determination of sofosbuvir and ledipasvir in human plasma using antiviral daclatasvir as an internal standard (IS). Liquid-liquid extraction of samples was used for the purification and preconcentration of the analytes from a human plasma matrix. Good and consistent recoveries were obtained, with average extraction recoveries of 91.61 and 88.93% for sofosbuvir and ledipasvir, respectively. The chromatographic separation of the three analytes was achieved within only 2.8 min by an isocratic mobile phase consisting of 10 mM ammonium acetate, which was then adjusted to pH 4.0 by acetic acid-acetonitrile-0.1% methanolic formic acid (12 + 25 + 63, v/v/v) flowing through a C18 Zorbax eclipse plus column (5 µm, 100 × 4.6 mm; Agilent). Multiple reaction monitoring transitions were measured in positive ion mode for sofosbuvir, ledipasvir, and daclatasvir (IS). A detailed validation of the method was performed and the standard curves were found to be linear in the range of 0.5 to 2500 and 5 to 2100 ng/mL for sofosbuvir and ledipasvir, respectively, applying weighted (1/X(2)) linear regression. The developed method was applied to the analysis of the two drugs after a single oral administration of Harvoni 400/90 mg film-coated tablets containing 400 mg sofosbuvir and 90 mg ledipasvir to four healthy volunteers.
Subject(s)
Benzimidazoles/blood , Benzimidazoles/isolation & purification , Fluorenes/blood , Fluorenes/isolation & purification , Sofosbuvir/blood , Sofosbuvir/isolation & purification , Chromatography, Liquid , Humans , Molecular Structure , Tandem Mass SpectrometryABSTRACT
Curcumin conjugated ZnO, referred as Zn(cur)O, nanostructures have been successfully synthesized, these sub-micro grain-like structures are actually self-assemblies of individual needle-shaped nanoparticles. The nanostructures as synthesized possess the wurtzite hexagonal crystal structure of ZnO and exhibit very good crystalline quality. FT-Raman and TGA analysis establish that Zn(cur)O is different from curcumin anchored ZnO (ZnO@cur), which is prepared by physically adsorbing curcumin on ZnO surfaces. Chemically Zn(cur)O is more stable than ZnO@cur. Diffuse reflectance spectroscopy indicates Zn(cur)O have more impurities compared to ZnO@cur. The solid-state photoluminescence of Zn(cur)O has been investigated, which demonstrates that increase of curcumin concentration in Zn(cur)O suppresses visible emission of ZnO prepared through the same method, this implies filling ZnO defects by curcumin. However, at excitation wavelength 425 nm the emission is dominated by fluorescence from curcumin. The study reveals that Zn(cur)O can remove to a far extent high concentrations of perylene, fluoranthene, and chrysene faster than ZnO. The removal depends on the extent of curcumin conjugation and is found to be faster for PAHs having smaller number of aromatic rings, particularly, it is exceptional for fluoranthene with 93% removal after 10 minutes in the present conditions. The high rate of removal is related to photo-degradation and a mechanism has been proposed.