Search

While depsidones, depsides or dibenzofuran-like compounds dominate the chemical composition of lichens, the cyanolichen Nephroma laevigatum affords a diversity of quinoid pigments represented by chlorinated anthraquinones derived from emodin and new bianthrones resulting from the homo- or heterodimerization of monomers. Bianthrones were pointed out from the dichloromethane extract by MS/MS-based molecular networking, then isolated and characterized on the basis of extensive spectroscopic analyzes and GIAO NMR shift calculation followed by CP3 analyzes., (Copyright © 2020 Elsevier B.V. All rights reserved.)

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 1 H and 13 C 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., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The soil microbial fuel cells (SMFCs) were constructed to remediate soils contaminated by polycyclic aromatic hydrocarbons (PAHs). With a maximum power density of 12.1mWm -2 and an internal resistance of 470Ω, a closed SMFC showed electricity generation comparable to that by an open SMFC after 175days of operation and meanwhile increased the removal rates of anthracene, phenanthrene, and pyrene to 54.2±2.7%, 42.6±1.9% and 27.0±2.1% from 20.8±1.1%, 17.3±1.2% and 11.7±0.9%, respectively, by the open SMFC. Both the electricity generation and the removal of PAHs increased with the decreased electrode interval. When the electrode interval ranged between 4cm and 10cm, the more closely the electrodes were positioned, the more efficient the electricity generation and removal of PAHs became. Dominated by the genus of Geobacter, the SMFC was enriched in electrogenic bacteria at the anode surface, and the growth of certain microbes other than electrogenic bacteria in the soil was improved by electrical stimulation. This finding reveals the critical mechanism underlying electricity generation and improved the removal of PAHs., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The ethanolic extract of Aloe barbadensis Miller leaf skin showed inhibitory activity against phosphodiesterase-4D (PDE4D), which is a therapeutic target of inflammatory disease. Subsequent bioassay-guided fractionation led to the isolation of two new anthrones, 6'-O-acetyl-aloin B (9) and 6'-O-acetyl-aloin A (11), one new chromone, aloeresin K (8), together with thirteen known compounds. Their chemical structures were elucidated by spectroscopic methods including UV, IR, 1D and 2D NMR, and HRMS. All of the isolates were screened for their inhibitory activity against PDE4D using tritium-labeled adenosine 3',5'-cyclic monophosphate ((3)H-cAMP) as substrate. Compounds 13 and 14 were identified as PDE4D inhibitors, with their IC50 values of 9.25 and 4.42 μM, respectively. These achievements can provide evidences for the use of A. barbadensis leaf skin as functional feed additives for anti-inflammatory purpose., (Copyright © 2014 Elsevier B.V. All rights reserved.)

7-O-methylvariecolortide A (1), variecolortide B (2), and variecolortide C (3), the rare variecolortides existing in racemic manner, were isolated from an endolichenic fungal strain Eurotium sp. (No. 17-11-8-1). With the chiral HPLC technology, (-)-(S)-7-O-methylvariecolortide A (1a), (+)-(R)-7-O-methylvariecolortide A (1b), (-)-(S)-variecolortide B (2a), (+)-(R)-variecolortide B (2b), (-)-(S)-variecolortide C (3a), and (+)-(R)-variecolortide C (3b) were successfully separated and obtained. Their absolute configurations were firstly assigned by ECD experiment and ECD calculation. According to the relation of isolated compounds, a plausible biosynthetic pathway for variecolortides was proposed. In caspase-3 enzymatic assay, compounds 1-3 showed inhibitory activity, with IC50 values of 1.7, 0.8 and 15.7 μM, respectively., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Six C-glucosyl anthrones were characterized as three pairs of epimers by on-line high performance liquid chromatography-circular dichroism (HPLC-CD) analysis and isolated from the roots of Rumex dentatus by column chromatography. Their structures were elucidated by mass spectrometry, nuclear magnetic spectroscopy and HPLC-CD analysis. They are 10R-C-beta-D-glucosyl-10-hydroxyemodin-9-anthrone (rumejaposide E, 1) and 10S-C-beta-D-glucosyl-10-hydroxyemodin-9-anthrone (rumejaposide F, 2), 10R-C-beta-D-glucosylemodin-9-anthrone (rumejaposide G, 3) and 10S-C-beta-D-glucosylemodin-9-anthrone (rumejaposide H, 4), 10S-C-beta-D-glucosyl-10-hydroxychrysophanol-9-anthrone (cassialoin, 5) and 10R-C-beta-D-glucosyl-10-hydroxychrysophanol-9-anthrone (rumejaposide I, 6). Rumejaposides F-I (2-4 and 6) were new C-glucosyl anthrones. Rumejaposide E (1) and cassialoin (5) were isolated for the first time in Rumex plants. On-line HPLC-UV-CD analysis was a useful tool for structure elucidating epimeric C-glycosides anthrones 3-6 because of the poor stability of the pure isomers (3 and 4) and the minute quantity of 5 and 6 in the mixture., (2010 Elsevier B.V. All rights reserved.)

Several studies have been performed reporting antitumoral activity of different mushroom extracts. The current study reports the antiproliferative activity of flavomannin-6,6'-dimethylether obtained from a very common edible mushroom: Tricholoma equestre(L.)P.Kumm, and the characterization of its effects at molecular level. Concentrations causing 50% and 80% growth inhibition on human adenocarcinoma colorectal Caco-2 cells were determined (in microg/mL: IC(50)=96+/-3 after 24 h and 78+/-7 after 48 h, IC(80)=112+/-4 after 24 h and 90+/-3 after 48 h) by using MTT method. It was demonstrated that flavomannin-6,6'-dimethylether induced an arrest in G0/G1 phase of the cell cycle by flow cytometry analysis and an increase of p27 protein level by Western blot. Furthermore, this compound did not induce apoptosis by flow cytometry or DNA fragmentation by gel electrophoresis. Thus, it could be a promising agent due to its cytostatic effect against Caco-2 tumoral cells, and the absence of a genotoxic effect.

Fabrication of porous frits to retain stationary phases is a critical issue in column preparation for capillary electrochromatography (CEC). In this work, porous frits were prepared by applying an external magnetic field to magnetically responsive particles placed inside a fused-silica capillary. Three batches of uniform magnetite spheres with particle diameters of 0.3, 0.4, and 0.6 microm and saturation magnetization values of 73.03, 74.41, and 77.83 emu/g, respectively, were used as frit particles and octadecyl- and phenyl-bonded silica gels were packed successfully into frit-containing capillaries. The performance of the resulting magnetically immobilized frits and packed columns was evaluated. The electroosmotic mobilities in capillaries containing outlet frit only were found to be reduced by 2-4% whereas the plate heights of an unretained marker increased by 30-50% as compared to those in open capillaries. These variations are believed to be associated with the inhomogeneities of the packed structure of the frits. The magnetically immobilized frits showed adequate mechanical strength to withstand the flow drag force, allowing separation in capillaries packed with 5-mum stationary phases up to 10-15 cm, thus rendering column efficiency and reproducibility comparable with those obtained with sintered frits. Taken together, retaining frits made of uniform magnetite particles serves as a viable alternative to sintered frits for column preparation, which offers several distinct advantages such as ease of preparation, improved durability as compared to sintered frits where the removal of the polyimide coating makes the packed column susceptible to breakage, and use of large-bore capillaries for semipreparative separations.

The characterization of a poly(dimethylsiloxane) (PDMS) thin film for active extraction of some polycyclic aromatic hydrocarbons was investigated in both a 1-L aqueous solution and a flow-through system. The thin film was attached to an electric bench-drill at a constant rotation speed for constant agitation and fast extraction. The performance of a PDMS-coated stir bar at a constant stirring speed was also investigated. The comparison showed that the extraction rate was much higher when using the thin film than the stir bar, and that the equilibration time was greatly shortened due to the larger surface area/volume ratio of the thin film. The extraction rate was roughly proportional to surface area of the extraction phase during the initial stage of the extraction process; the amount of analyte extracted was proportional to the ratio of the extraction phase between the thin film and the stir bar. Different agitation and stirring rates of the thin film and stir bar were applied for extraction, revealing that extraction efficiency can be improved by increasing rotation rate. The application of rotated thin film in the field proved it is a valid and easily operated method for the determination of polycyclic aromatic hydrocarbons (PAHs) in a campus river. However, the stir bar is not as convenient as a thin film in field sampling.

We report the aqueous solubilities of phenanthrene and several solid three-ring aromatic heterocycles (phenanthridine, acridine, phenazine, thianthrene, phenothiazine, phenoxathiin, phenoxazine, carbazole, dibenzofuran, dibenzothiophene, and 4,6-dimethyldibenzothiophene) at temperatures ranging from 313K to the solute melting point and at a pressure of 5MPa. The data were measured by dynamic saturation method using an in-house-assembled apparatus for pressurized hot water extraction (PHWE). The solute from a known mass of the saturated aqueous solution was transferred to an organic solvent (hexane or toluene), and the organic phase was analyzed by GC/MS. In any of the solutes, the GC/MS records did not indicate any noticeable decomposition within the temperature range of the measurements. The resultant solubilities were converted to activity coefficients of the individual solutes in saturated aqueous solutions, and the results are discussed in terms of temperature and type/number of heteroatoms.

The in vitro activity of some isolated hydroxyanthracenones belonging to the genus Karwinskia against four bacteria, six filamentous fungi and four yeast are reported. These hydroxyanthracenones were found to possess antimicrobial activity, particularly against Streptococcus pyogenes, Candida albicans, C. boidinii, C. glabrata and Cryptococcus neoformans; minimal inhibitory concentrations range between 16 and 2 microg/ml.

Three types of thiol compounds (n-octadecanethiol, thiophenol, and 2-phenylethanethiol) were used to modify the gold-coated polystyrene particles (dp. 5microm) to prepare a stationary phase for capillary liquid chromatography through the formation of self-assembled monolayer. The column with n-octadecanethiol-modified gold-coated polystyrene particles (C18-Au) demonstrated the higher affinity to phenanthrene and anthracene than small aromatics compared to the ODS column. In addition, the shape selectivity between phenanthrene and anthracene in the C18-Au column was much higher than that in the ODS column (separation factors: 1.82 and 1.14, respectively). The relationship between the retention factor and acetonitrile content in the mobile phase revealed that the retention behaviors in the C18-Au column was more sensitive on the acetonitrile content than those in the ODS column. Relatively higher affinity for phenanthrene and anthracene was commonly observed in all the three thiol-modified Au columns than that for the conventional ODS column, whereas separations of benzene and nitro- and chlorobenzenes were quite different among the three thiol-modified Au and ODS columns.

A novel silica-bonded stationary phase containing a functionalized resorcinarene selector was prepared by a straightforward synthesis. The complete modification of all resorcinic hydroxyl groups was achieved by reaction with isopropyl isocyanate. The derivatized resorcinarene selector was subsequently immobilized via the four alkenyl chains containing a terminal double bond by a free radical-induced reaction on mercaptopropyl-functionalized silica. A comprehensive characterization of the resulting bonded stationary phase was carried out by solid state NMR, IR and elemental analysis. The resulting selector is defined as a "polar headed" reversed phase since the highly ordered polar carbamate groups of the new stationary phase are located, compared to conventional polar embedded stationary phases, at a greater distance from the silica surface. Thus a new concept is introduced in the field of polar modified reversed-phase HPLC. The properties of the novel stationary phase are demonstrated by comparison with commercially available reversed phases.

The enantioseparation of 2,2,2-trifluoro-1-(9-anthryl)ethanol on silica-bonded quinidine carbamate was examined under linear chromatographic conditions. The significant impact of nonselective adsorption on the retention was demonstrated. The influences of a polar additive in the mobile phase on the retention, the selectivity and the thermodynamic quantities of the retention were measured. A small effect of the pressure on the selectivity and on the accuracy of the thermodynamic measurements was observed.

Soil column experiments were conducted to investigate the effect of ozonation duration, contaminant content, particle size, moisture content, OH radical scavenger and soil organic matter on the removal of anthracene by in situ ozonation. In the whole study, the gas flow rate was 100 mL/min and concentration of gaseous ozone was 40 mg/L. The removal efficiency increased with the elapsed time, but the removal rate decreased in the range of 0-90 min. As anthracene content in sand decreased from 50 to 10 mg/kg, the removal efficiency increased from 42.1% to 62.0%, and ozone passed through soil column more rapidly. However, the ozone effectiveness reduced when anthracene content dropped. Small particle size provides a large interfacial area, which led to the high removal efficiency and long ozone breakthrough time in the column. The profile of residual anthracene in soil column varied more greatly at smaller particle size. The removal efficiency reduced when the moisture content rose from 0% to 9.1%. The ozone breakthrough time also decreased with the increasing moisture content. The presence of sodium bicarbonate or humic acid reduced the removal efficiency to some extent. GC-MS was employed in this study to determine 9,10-anthraquinone as the main ozonation product.

The atropisomeric austrocolorins A(1) (7) and B(1) (8), new members of the rare tricolorin class of 10,10'-coupled dihydroanthracenones, are isolated from an indigenous Australian toadstool belonging to the subgenus Dermocybe of Cortinarius, and their structure and absolute central and axial configuration is deduced from the spectroscopic data, and confirmed by chemical degradation and chiral HPLC analysis.

From the aerial parts of Rubus ulmifolius Schott three new anthrones, rubanthrone A, B and C, have been isolated. Their structures were established by spectral procedures including 1D and 2D NMR techniques and chemical derivatization. Rubanthrone A showed antimicrobial activity against Staphylococcus aureus at 4.5 mg/ml.

From the roots of Cassia kleinii two new oxanthrone esters, kleinioxanthrone-3 and kleinioxanthrone-4 have been isolated. Their structures were established as 1,8-dihydroxy-3-methyl-9(10H)-anthracenone-10-oxyhexadecanoate 3 and 2,6,7-trihydroxy-1,8-dimethoxy-3-methyl-9(10H)-anthracenone-10-oxydecanoate 4 respectively based on degradative and spectroscopic evidence.

High-speed counter-current chromatography was successfully applied to the large-scale separation of resveratrol, anthraglycoside A and anthraglycoside B from the crude extract of Polygonum cuspidatum Sieb. et Zucc using a two-phase solvent system composed of chloroform, methanol and water. Resveratrol, anthraglycoside A and anthraglycoside B were separated from multigram quantities (5 g) of crude extract of P. cuspidatum. The separation yielded 200 mg to 1 g of these three compounds each at over 98% purity as determined by HPLC. The chemical structures of these components were identified by nuclear magnetic resonance (NMR) and MS.

From the aerial parts of Cassia kleinii two new oxanthrone esters, kleinioxanthrone-1 and kleinioxanthrone-2 have been isolated. Their structures were established as 1,8-dihydroxy-3-methyl-6-methoxy-9(10H)-anthracenone-10-oxydecanoate 1 and 1,8-dihydroxy-3-methyl-9(10H)-anthracenone-10-oxytetradecanoate 2 respectively based on degradative and spectroscopic evidence.

Three anthracene derivatives, auxenone, oncocalyxonol and auxemim, were isolated from Auxemma ontocalyx. The structures of these compounds as 1,4,8-trihydroxy-2-methoxy-5-methyl-9,10-anthraquinone, rel-9alpha,11alpha-epoxy-1,4,8alpha,11alpha-tetrahydroxy-2-methoxy-8a beta-methyl-5,6,7,8,8a,9, 10,10a beta-octahydro-10-anthracenone and rel-8alpha,11beta-epoxy-2,11-dimethoxy-8a beta-methyl-5,6,7,8,8a,9-hexahydro-1,4-anthracenedione were determined by analysis of spectral data (1D and 2D NMR, IR, HREIMS and UV).

A phytochemical investigation of the leaf exudate of Aloe marlothii has resulted in the isolation of a new chromone (7-O-methylaloeresin A) and a new anthrone (5-hydroxyaloin A 6'-O-acetate). Furthermore 7-O-methylaloesin was isolated as a natural product for the first time from the leaf exudate of Aloe rupestris. The structure elucidation of these compounds was based on spectral data including 2D NMR. The chemotaxonomic value of 7-O-methylaloesin in Aloe series Asperifoliae and section Pachydendron is discussed.

An azaanthracene alkaloid, 1-aza-9,10-dimethoxy-4-methyl-2-oxo-1,2-dihydroanthracene (kalasinamide) has been isolated from the stems of Polyalthia suberosa. In addition, the known N-trans-feruloyltyramine and N-trans-coumaroyltyramine are also reported from the same source. The structures were elucidated by spectroscopic methods.

Tullidinol, a neurotoxin isolated from fruits and roots of several Karwinskia species, was resolved for the first time into two stereoisomers. This was achieved by means of preparative HPLC from roots of Karwinskia parvifolia. Structural assignments were made on the basis of spectroscopic data, including long range correlations as well as geometry optimization by means of semi-empirical methods.

The stem and leaves of Gasteria bicolor afforded three new dihydroanthracenones namely 3,4-dihydro-2,6,9-trihydroxy-8-methyl-1(2H)-anthracenone (gasteriacenone A), 3,4-dihydro-2,4,9-trihydroxy-6-methoxy-8-methyl-1(2H)-anthracenone (gasteriacenone B) and 3,4-dihydro-4,6,9-trihydroxy-7-carbomethoxy-8-methyl-1(2H)-anthraceno ne (gasteriacenone C). Their structures were determined by spectroscopic methods including 2D NMR techniques.

From suspension cultures of Cassia didymobotrya 7-acetylchrysophanol, chrysophanol-physcion-l0,l0'-bianthrone, (E)- and (Z)-3'-hydroxy-3,4,5'-trimethoxystilbene, (E)-4,3'-dihydroxy-3,5'-dimethoxystilbene and 7,4'-dihydroxy-3,5,3'-trimethoxyflavone have been isolated along with several known metabolites.

Strategies are outlined for the separation of biologically active products of plant origin. The techniques involved include low-pressure liquid chromatography, semi-preparative high-performance liquid chromatography, flash chromatography and droplet counter-current chromatography. Their application to the isolation of compounds from Sesamum angolense (Pedaliaceae), Psorospermum febrifugum (Guttiferae) and Cordia goetzei (Boraginaceae) is described.

A preparation method for 9-anthryldiazomethane (ADAM) as a fluorescent labeling reagent for carboxylic acids is described. 9-Anthraldehyde hydrazone is oxidized with an organic oxidant, N-chlorosuccinimide, in an organic solvent such as ethyl acetate to give ADAM, and then the reaction mixture is directly used as the reagent solution for the derivatization of carboxylic acids. Both the oxidation and the derivatization reaction are carried out at room temperature, and an aliquot of the derivatization mixture is directly injected into a chromatograph. 9-Anthrylmethyl ester derivatives formed from ADAM and various carboxylic acids are sufficiently separated on a reversed-phase column and are sensitively detected fluorometrically. The present method was applied to the high-performance liquid chromatographic determination of long and short chain fatty acids, keto acids, and hydroxy acids.

Anthralin and its decomposition products were separated by both column chromatographic and TLC techniques. Two decomposition products were characterized by TLC, melting-point data, and UV and IR spectroscopy. Pure anthralin and its decomposition products also were determined quantitatively.