Sorption of carbendazim and linuron from aqueous solutions with activated carbon produced from spent coffee grounds: Equilibrium, kinetic and thermodynamic approach.

Spent coffee grounds (SCG) have been used for the production of activated carbon (AC) by impregnation with different ratios of phosphoric acid at 600 °C, Xp (H3PO4/coffee): 3:130%, 4:130%, 3:150% and 4:150%. The obtained AC was characterized by BET, FTIR and SEM. BET surface area corresponds to 803.422 m2 g-1. The influences of the main parameters such as contact time, the pesticides initial concentration, adsorbent dose, pH and temperature on the efficiency of separation process were investigated during the batch operational mode. Results were modeled by adsorption isotherms: Langmuir, Freundlich and Temkin isotherms, which gave satisfactory correlation coefficients. The maximum adsorption capacities calculated from the Langmuir isotherms were 11.918 mg g-1 for carbendazim and 5.834 mg g-1 for linuron at room temperature. Adsorption kinetics of carbendazim and linuron have been studied by the pseudo-first-order, the pseudo-second-order and the intraparticle diffusion model. The results of adsorption kinetics have been fitted the best by pseudo-second-order model. The resulted data from FTIR characterization pointed to the presence of many functional groups on the AC surface. SCG adsorbent, as an eco-friendly and low-cost material, showed high potential for the removal of carbendazim and linuron from aqueous solutions.

Anti-inflammatory constituents from Psychotria prainii H. Lév.

One new and three known compounds were isolated from the ethanol extract of Psychotria prainii aerial parts. By means of spectroscopic methods, their structures were elucidated to be deacetylasperulosidic acid 6-ethyl ether (1), asperulosidic acid (2), asperuloside (3) and obtucarbamates C (4). The isolated compounds were evaluated for their inhibitory effect on NO production in LPS-stimulated RAW264.7 cells. Among them, compounds 2 and 4 exhibited strong effect with the IC50 values of 5.75 ± 0.85 and 6.92 ± 0.43 µM, respectively. This is the first report for the chemical composition and biological activity of P. prainii.

Lifecycle modelling systems support inosine monophosphate dehydrogenase (IMPDH) as a pro-viral factor and antiviral target for New World arenaviruses.

Infection with Junín virus (JUNV) is currently being effectively managed in the endemic region using a combination of targeted vaccination and plasma therapy. However, the long-term sustainability of plasma therapy is unclear and similar resources are not available for other New World arenaviruses. As a result, there has been renewed interest regarding the potential of drug-based therapies. To facilitate work on this issue, we present the establishment and subsequent optimization of a JUNV minigenome system to a degree suitable for high-throughput miniaturization, thereby providing a screening platform focused solely on factors affecting RNA synthesis. Using this tool, we conducted a limited drug library screen and identified AVN-944, a non-competitive inosine monophosphate dehydrogenase (IMPDH) inhibitor, as an inhibitor of arenavirus RNA synthesis. We further developed a transcription and replication competent virus-like particle (trVLP) system based on these minigenomes and used it to screen siRNAs against IMPDH, verifying its role in supporting arenavirus RNA synthesis. The antiviral effect of AVN-944, as well as siRNA inhibition, on JUNV RNA synthesis supports that, despite playing only a minor role in the activity of ribavirin, exclusive IMPDH inhibitors may indeed have significant therapeutic potential for use against New World arenaviruses. Finally, we confirmed that AVN-944 is also active against arenavirus infection in cell culture, supporting the suitability of arenavirus lifecycle modelling systems as tools for the screening and identification, as well as the mechanistic characterization, of novel antiviral compounds.

Simultaneous determination of organophosphorus, organochlorine, pyrethriod and carbamate pesticides in Radix astragali by microwave-assisted extraction/dispersive-solid phase extraction coupled with GC-MS.

A simple, rapid and reliable method was proposed for the simultaneous determination of 27 pesticides (organophosphorus, organochlorine, pyrethroid and carbamate pesticides) in Radix astragali. The pesticides were extracted by acetonitrile and the experimental variables, such as temperature, extraction time and volume of acetonitrile, were optimized through orthogonal array experimental design. Cleanup of extracts was performed with dispersive-solid phase extraction using primary secondary amine (PSA) as the sorbent. The determination of pesticides in the final extracts was carried out by gas chromatography-mass spectrometry in selected ion monitoring mode (GC-MS, SIM). The linearity of the calibration curves is good in matrix-matched standard, and yields the coefficients of determination (R(2))≥0.99 for approximately 96% of the target analytes. Under optimized conditions, the average recoveries (six replicates) for most pesticides (spiked at 0.02, 0.1 and 0.2 mg kg(-1)) range from 70% to 120%, and RSDs are less than 17.2%.

Microwave accelerated selective Soxhlet extraction for the determination of organophosphorus and carbamate pesticides in ginseng with gas chromatography/mass spectrometry.

Microwave accelerated selective Soxhlet extraction (MA-SSE), a novel selective extraction technique, was investigated in this study. A Soxhlet extraction system containing a glass filter was designed as an extractor. During the procedure of MA-SSE, both the target analytes and the interfering components were extracted from the sample into the extraction solvent enhanced by microwave irradiation. After the solvent flowed though the sorbent, the interfering components were adsorbed by the sorbent, and the target analytes remaining in the solvent were collected in the extraction bottle. No cleanup or filtration was required after extraction. The efficiency of the MA-SSE approach was demonstrated in the determination of organophosphorus and carbamate pesticide residues in ginseng by gas chromatography/mass spectrometry (GC/MS). Under the optimized conditions, low limits of detection (0.050-0.50 µg/kg) were obtained. The recoveries were in the range of 72.0-110.1% with relative standard deviations less than 7.1%. Because of the effect of microwave irradiation, MA-SSE showed significant advantage compared with other extraction techniques. The sorbent used in this study showed good cleanup ability. The mechanism of MA-SSE was demonstrated to be based on the rupture of the cell walls according to the structural changes of ginseng samples. On the basis of the results, MA-SSE as a simple and effective sample preparation technique for the analysis of pesticide residues in complex matrixes shows great promise.

A new carbamate with cytotoxic activity from the aerial parts of Siegesbeckia pubecens.

AIM: To study the chemical constituents of Siegesbeckia pubescens. METHODS: The chemical constituents were isolated by extraction, crystallization and various chromatographic methods, and the chemical structures were elucidated on the basis of spectral analysis. In addition, the cytotoxic activity of compound 1 was evaluated using human lung cancer cell A 549. RESULTS: Four compounds were obtained, and their structures were identified as (E)-3-(3-oxobut-1-enyl)phenyl dimethylcarbamate (1), ent-2-oxo-15, 16, 19-trihydroxypimar-8(14)-ene (2), 16-acetylkirenol (3), 3, 7-dimethylquercetin (4). CONCLUSION: Compound 1 is a new carbamate, and the IC(50) in MTT method of compound 1 was 58 µg·mL(-1).

Preventative effects of 4,4'-diphenylmethane-bis(methyl) carbamate isolated from cortex mori on human umbilical vein endothelial cell dysfunction induced by advanced glycation end products.

Advanced glycation end-products (AGEs) have been regarded as an initial motivating factor in the pathogenesis of endothelial dysfunction in diabetic complications. 4,4'-Diphenylmethane-bis(methyl) carbamate (DMPC), a carbamate compound, was isolated from Cortex Mori and its prevention effects against AGEs-induced endothelial dysfunction were studied. 4,4'-Diphenylmethane-bis(methyl) carbamate significantly reduced cell apoptosis to normal level at 10⁻9 mol/L concentration. Advanced glycation end-products up-regulated the expression of Bad and Bax and down-regulated Bcl-2 proteins, and pretreatment with DMPC significantly down-regulated Bad and Bax while up-regulating Bcl-2 expressions. In addition, ICAM (intercellular adhesion molecule)-1 and TGF (transforming growth factor)-ß1 expressions in human umbilical vein endothelial cell (HUVEC) were significantly enhanced by AGEs. More importantly, these increases of ICAM-1 and TGF-ß1 expressions were reduced meaningfully with the pretreatment of DMPC. All the results showed DMPC had prevention effects against the progression of AGE-induced endothelial dysfunction, and this compound might be a promising agent against endothelial dysfunction in diabetic vascular complications.

Dispersive solid-phase extraction cleanup combined with accelerated solvent extraction for the determination of carbamate pesticide residues in Radix Glycyrrhizae samples by UPLC-MS-MS.

Dispersive solid-phase extraction (DSPE) cleanup combined with accelerated solvent extraction (ASE) is described here as a new approach for the extraction of carbamate pesticides in Radix Glycyrrhizae samples prior to UPLC-MS-MS. In the DSPE-ASE method, 15 carbamate pesticides were extracted from Radix Glycyrrhizae samples with acetonitrile by the ASE method at 60 °C with a 5 min heating time and two static cycles. Cleanup of a 1 mL aliquot of the extract by the DSPE method used 20 mg PSA (primary secondary amine), 50 mg Al(2)O(3)-N, and 20 mg GCB (graphitized carbon black) (as cleanup sorbents) under the determined optimum conditions. The linearity of the method was in the range of 10 to 200 ng/mL with correlation coefficients (r(2)) of more than 0.996. The limits of detection were approximately 0.2 to 5.0 µg/kg. The method was successfully used for the analysis of target pesticides in Radix Glycyrrhizae samples. The recoveries of the carbamate pesticides at the spiking levels of 50, 100, and 200 µg/kg ranged from 79.7% to 99.3% with relative standard deviations lower than 10%. This multi-residue analytical method allows for a rapid, efficient, sensitive and reliable determination of target pesticides in Radix Glycyrrhizae and other medicinal herbs.

Dibromotyrosine and histamine derivatives from the tropical marine sponge Aplysina sp.

Two new compounds, 3-amino-7,8-dihydroimidazo-[1,5-c]-pyrimidin-5(6H)-one (1) and ethyl 3-(2-amino-1H-imidazol-4-yl)propylcarbamate (2), along with the previously known 7,8-dihydroimidazo-[1,5-c]-pyrimidin-5(6H)-one (3), aeroplysinin-1 (4), dibromoverongiaquinol (5), bisoxazolidinone derivative (6), aerophobins-1 (7) and -2 (8), purealidins J (9) and L, have been isolated from Aplysina sp. from the South China Sea. The structures were elucidated on the basis of 1H, 13C NMR, MS and IR analyses. The histamine-derived alkaloids 1-3 may be unknown bioconversion products of purealidin J (9), aerophobin-2 (8) and aerophobin-1 (7), respectively, when 7-9 are cleaved at C-8-C-9 in reactions of activated chemical defense in Aplysina sponge.

Application of dual counter-current chromatography for rapid sample preparation of N-methylcarbamate pesticides in vegetable oil and citrus fruit.

Dual counter-current chromatography (dual CCC) has been successfully applied to rapid sample preparation for the simultaneous determination of residual carbaryl, fenobucarb and methomyl in vegetable oil and citrus fruit. The citrus fruit samples were extracted with n-hexane solution containing stable isotopically labeled internal standards (methomyl-d3, fenobucarb-d3 and carbaryl-d9), and applied to dual CCC using a two-phase solvent system of n-hexane-acetonitrile to purify the carbamate pesticides from aliphatic sample matrix. The coiled column was rotated at 420 rpm, the lower mobile phase was introduced through the head toward the tail, and the upper mobile phase in the opposite direction. Due to the high partition efficiency of dual CCC, the lower phase fraction collected from 2 to 5 min after injection could be subjected to flow-injection tandem mass spectrometry directly after concentration. Repetitive sample injection can be performed at high reproducibility without a risk of contamination from the compounds retained in the column.

A simple and quick gas chromatographic method for the determination of propham and chlorpropham in potatoes.

This study describes a gas chromatographic method for the quantitative determination of residual propham and chlorpropham in potatoes. Both herbicides are extracted from the foodstuff with methylene chloride. After centrifugation and concentration, propham and chlorpropham are quantitatively determined by gas chromatography thermionic detection using a fused silica capillary column CP Sil 5CB. 2-Chloraniline is used as internal standard. Recoveries of 100 +/- 15% and 99 +/- 10% have been obtained for propham and chlorpropham in blank samples spiked at the level of 0.5, 1.0 and 5.0 mg/kg. The absolute detection limit for both compounds is 1 ng corresponding to 0.1 mg/kg. Of the 161 samples of fresh potatoes analysed using this method, 136 contained residues of these herbicides and 18 of them (11%) exceeded the maximum tolerated value of 5 mg/kg.

N-carbamoyl-2-(p-hydroxyphenyl)glycine from leaves of broad bean (Vicia faba L.).

1. dl-2-(p-Hydroxyphenyl)glycine was resolved through the bromocamphorsulphonate to give its d-isomer. The N-carbamoyl derivatives of these amino acids were synthesized. Circular-dichroism studies on these and related compounds, reported in a deposited Annex, helped to establish the optical configuration. 2. N-Carbamoyl-dl-2-(p-hydroxyphenyl)glycine was isolated from broad-bean leaves. It amounted to about 0.1% of the leaf dry matter. Racemization may or may not have occurred during the isolation. There were indications of the same compound in chicory and in savoy cabbage. Under weakly acidic conditions it was converted gradually into 5-(p-hydroxyphenyl)hydantoin. Both these compounds yielded 2-(p-hydroxyphenyl)glycine on acid hydrolysis. 3. The occurrence is discussed of 2-phenylglycine derivatives in Nature and of N-carbamoyl-amino acids and hydantoins in plants. 4. Gradient elution from anion-exchange resin with acetic acid, besides proving useful for the present work, gave useful separations of pyrrolidonecarboxylic acid and of some N-acetyl-amino acids. 5. Supplementary material (Annex 1: details of experimental work other than ultraviolet and circular-dichroism spectra; Annex 2: ultraviolet absorption and circular dichroism of d-2-phenylglycine and some related compounds) has been deposited as Supplementary Publication SUP 50003 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1971), 121, 7.