Plant Density and Rhizosphere Chemistry: Does Marigold Root Exudate Composition Respond to Intra- and Interspecific Competition?

The development of techniques to non-destructively monitor allelochemical dynamics in soil using polydimethylsiloxane (PDMS) microtubing (silicone tubing microextraction, or STME) provides a means to test important ecological hypotheses regarding the roles of these compounds in plant-plant interactions. The objective of this study was to investigate the impact of intra- and interspecific competition on the exudation of thiophenes by marigolds (Tagetes patula L.). Marigolds were grown at a density of 1, 3 and 5 plants in pots (8.75 × 8.75 cm) containing two STME samplers. An additional treatment included one marigold surrounded by four velvetleaf (Abutilon theophrasti L.) plants. Marigold roots released two primary thiophenes, 3-buten-1-ynyl)-2,2'-bithienyl and α-terthienyl, which are readily absorbed by silicone microtubing. Thiophene exudation was monitored over the period 15-36 days after planting, at 2-5 day intervals. At the end of the study, root and soil samples were also analyzed for thiophene content. Thiophene production per plant increased over time, and thiophene release was strongly correlated with plant size. These results indicate that thiophene release in this study was passively controlled by resource availability. However, poor growth of velvetleaf plants competing with marigold suggests that thiophenes negatively influenced velvetleaf growth. This study, then, provides indirect evidence that thiophene exudation is insensitive to neighbor identity but differentially effective in inhibiting the growth of heterospecific neighbors.

Two new thiophene polyacetylene glycosides from Atractylodes lancea.

Phytochemical investigation on the rhizomes of Atractylodes lancea led to the isolation of two new thiophene polyacetylene glycosides (1 and 2) and six known compounds (3-8). Their structures were elucidated based on the extensive spectroscopic data (UV, IR, 1D and 2D NMR, and HRESIMS). The absolute configurations of new compounds were established by calculated and experimental circular dichroism. All the compounds were assessed on the lipopolysaccharide-induced NO production in BV2 cells and compounds 3, 7, and 8 showed moderate inhibitory activities.

Effect of Temperature on Flavor Compounds and Sensory Characteristics of Maillard Reaction Products Derived from Mushroom Hydrolysate.

Maillard reaction products (MRPs) were prepared from mushroom hydrolysate (MH) by heating with d-xylose and l-cysteine at various temperatures (100 °C-140 °C) for 2 h at a pH of 7.4. The sensory characteristics of MH and MRPs were evaluated by panelists and volatile compounds were analyzed by GC/MS. Additionally, partial least squares regression (PLSR) was performed to analyze the correlation between quantitative sensory characteristics and GC/MS data. GC/MS results revealed that higher reaction temperature resulted in more nitrogen and sulfur containing compounds in MRPs while alcohols, ketones and aldehydes were the major flavor compounds obtained in MH. PLSR results showed that 3-phenylfuran and 2-octylfuran were the compounds responsible for the caramel-like flavor; 1-octen-3-ol, (E)-2-octen-1-ol and geranyl acetone were significantly and positively correlated to mushroom-like flavor, whereas, 2-thiophene-carboxaldehyde, 2,5-thiophenedicarboxaldehyde and 3-methylbutanal positively affected MRPs meat-like attribute. Overall, 125 °C was identified as the optimal temperature for preparing MRPs with abundant volatile compounds and favorable sensory characteristics; the concentration of free amino acids and 5'-GMP, which are associated with the umami taste, in MRPs derived under 125 °C were 3 to 4 times higher than those in MH.

New terpenoids and thiophene derivatives from the aerial parts of Artemisia sieversiana.

One new highly oxygenated nortriterpene, named sieverlactone (1), one new sesquiterpene, 1ß,10ß-epoxy-8α-acetoxyachillin (2), one new natural product, 5-propinyl-thiophene-2-carboxylic acid (3), and one new thiophene, 3-hydroxy-5-propinyl-2-acetyl-thiophene (4), together with 10 other known compounds (5-14), were isolated from the dried aerial parts of Artemisia sieversiana. Their structures were elucidated by a combination of extensive spectroscopic analysis, including 1D, 2D NMR spectroscopic and mass spectrometric data. Meanwhile, the stereochemistry of 1 and 2 was confirmed by single-crystal X-ray diffraction technique using Cu radiation. All the isolates were evaluated for their anti-neuroinflammatory effects on the lipopolysaccharide-induced nitric oxide production in BV-2 murine microglial cells. Compounds 2, 5, and 6 exhibited the significant activities with IC50 values of 6.5 ±â€¯0.5, 11.9 ±â€¯0.7, and 10.1 ±â€¯0.3 µM, respectively, comparable to the positive control, quercetin, with an IC50 value of 16.3 ±â€¯0.4 µM.

Chiral analysis of ammuxetine enantiomers in dog plasma using online SPE/liquid chromatography with tandem mass spectrometric detection after precolumn chiral derivatization.

Ammuxetine (AMT), a novel chiral antidepressant candidate compound, exhibits better antidepression effects than duloxetine in different animal models. In this article, a chiral derivatization method, combined with online solid phase extraction (online SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), was developed for the chiral separation of AMT enantiomers after administration of racemic AMT to dogs. The derivatization reaction employed 2,3,4,6-tetra-O-acetyl-b-glucopyr-anosyl isothiocyanate (GITC) as a precolumn chiral derivatization reagent. A SPE column Retain PEP Javelin (10 × 2.1 mm) was used to remove proteins and other impurities in plasma samples. The enantiomeric derivatives were separated on a ZORBAX SB-C18 column (50 × 2.1 mm × 3.5 µm) with an isocratic elution procedure. The selected multiple reaction monitoring mode of the positive ion was performed and the parent to the product transitions m/z 681.0/543.1 and m/z 687.4/543.1 were used to measure the derivatives of AMT and duloxetine (internal standard) with electrospray ionization. The method was validated in terms of specificity, linearity, sensitivity, precision, accuracy, matrix effect, and stability. The method was applied to a pharmacokinetics study of AMT racemate in dogs. The results suggested that the pharmacokinetic of AMT enantiomers might be stereoselective in dogs.

Inhibition of human cytochromes P450 2A6 and 2A13 by flavonoids, acetylenic thiophenes and sesquiterpene lactones from Pluchea indica and Vernonia cinerea.

The human liver cytochrome P450 (CYP) 2A6 and the respiratory CYP2A13 enzymes play role in nicotine metabolism and activation of tobacco-specific nitrosamine carcinogens. Inhibition of both enzymes could offer a strategy for smoking abstinence and decreased risks of respiratory diseases and lung cancer. In this study, activity-guided isolation identified four flavonoids 1-4 (apigenin, luteolin, chrysoeriol, quercetin) from Vernonia cinerea and Pluchea indica, four hirsutinolide-type sesquiterpene lactones 5-8 from V. cinerea, and acetylenic thiophenes 9-11 from P. indica that inhibited CYP2A6- and CYP2A13-mediated coumarin 7-hydroxylation. Flavonoids were most effective in inhibition against CYP2A6 and CYP2A13, followed by thiophenes, and hirsutinolides. Hirsutinolides and thiophenes exhibited mechanism-based inhibition and in irreversible mode against both enzymes. The inactivation kinetic KI values of hirsutinolides against CYP2A6 and CYP2A13 were 5.32-15.4 and 0.92-8.67 µM, respectively, while those of thiophenes were 0.11-1.01 and 0.67-0.97 µM, respectively.

Antifungal effect of volatile organic compounds produced by Bacillus amyloliquefaciens CPA-8 against fruit pathogen decays of cherry.

The present work focuses on the antifungal effect of volatile organic compounds (VOCs) produced by Bacillus amyloliquefaciens CPA-8 against Monilinia laxa, M. fructicola and Botrytis cinera, three postharvest fruit pathogens of sweet cherry fruit. VOCs were evaluated with a double petri dish assay against mycelial and colony growth of target pathogens. For this purpose, CPA-8 was grown on different media and cultured for 24 and 48 h at 30 °C before assays. Data showed that mycelial growth inhibition was higher when CPA-8 was grown on Tryptone Soya Agar (TSA) while no differences were generally observed when CPA-8 was cultured for either, 24 and 48 h. Moreover, no effects were observed on colony growth. The main volatile compounds emitted by CPA-8 were identified by solid-phase microextraction (SPME)-gas chromatography as 1,3 pentadiene, acetoin (3-hydroxy-2-butanone) and thiophene. Pure compounds were also tested in vitro on mycelial growth inhibition and their EC50 values against the three pathogens were estimated. Thiophene was the most effective VOC, showing more than 82% suppression of mycelial growth at the highest concentration (1.35 µL/mL headspace) and EC50 values ranging from 0.06 to 6.67 µL/mL headspace. Finally, the effectiveness of thiophene and CPA-8 VOCs was evaluated against artificially inoculated cherry fruits. Among the target pathogens, M. fructicola was clearly controlled by CPA-8 with less than 25% of rotten fruits compared to the control (65% disease incidence) and for all pathogens, less than 37.5% of CPA-8 treated decayed fruits produced spores (disease sporulation). Otherwise, pure thiophene showed no effect against any pathogen on disease incidence and disease sporulation. The results indicated that VOCs produced by B. amyloliquefaciens CPA-8 could develop an additive antifungal effect against postharvest fruit pathogens on stone fruit.

Atypical Cyclic Sulfides, Garlicnins G, I, and J, Extracted from Allium sativum.

Newly characterized, atypical sulfides, garlicnins G (1), I (2), and J (3), were isolated from the acetone extracts of garlic bulbs, Allium sativum. Their production pathways are regarded as different from those of cyclic sulfoxides, 3,4-dimethyltetrahydrothiophene-S-oxide derivatives such as onionins A1-A3, garlicnins B1-B4 and C1-C3.

Antimalarial Activity of Acetylenic Thiophenes from Echinops hoehnelii Schweinf.

Malaria is one of the world's most severe endemic diseases and due to the emergence of resistance to the currently available medicines, the need for new targets and relevant antimalarial drugs remains acute. The crude extract, four solvent fractions and two isolated compounds from the roots of Echinops hoehnelii were tested for their antimalarial activity using the standard four-day suppressive method in Plasmodium berghei-infected mice. The 80% methanol extract exhibited suppression of 4.6%, 27.8%, 68.5% and 78.7% at dose of 50, 100, 200 and 400 mg/kg respectively. The dichloromethane fraction displayed chemosuppression of 24.9, 33.5 and 43.0% dose of 100, 200 and 400 mg/kg of body weight. Five acetylenicthiophenes were isolated from the dichloromethane fraction of which 5-(penta-1,3-diynyl)-2-(3,4-dihydroxybut-1-ynyl)-thiophene decreased the level of parasitaemia by 43.2% and 50.2% while 5-(penta-1,3-diynyl)-2-(3-chloro-4-acetoxy-but-1-yn)-thiophene suppressed by 18.8% and 32.7% at 50 and 100 mg/kg, respectively. The study confirmed the traditional claim of the plant to treat malaria and could be used as a new lead for the development of antimalarial drugs.

Dimeric sesquiterpene and thiophenes from the roots of Echinops latifolius.

Phytochemical investigation of the roots of Echinops latifolius led to the isolation of a new carbon skeleton dimeric sesquiterpene (1) and a new thiophene (2), along with six known compounds (3-8). Their structures and relative stereochemistry were elucidated by spectroscopic and spectrometric methods (1H and 13C NMR, COSY, HSQC, HMBC, ROESY, and MS). All isolates were evaluated for their inhibition of LPS-induced NO production in RAW 264.7 cells. Compounds 4 and 5 exhibited the most potent inhibitory effects on NO production.

Study of the enantioseparation capability of chiral dual system based on chondroitin sulfate C in CE.

It has been reported that chiral dual system is able to improve the enantioseparation of enantiomers in many cases. Currently, the dual systems involved in CE chiral separation are mostly dual CDs systems, and the polysaccharides-based chiral dual system was reported in only one paper. To the best of our knowledge, the use of chondroitin sulfate C (CSC)-based dual system for enantiomeric separation has not been reported previously. Herein, four CSC-based chiral dual systems, namely CSC/glycogen, CSC/chondroitin sulfate A (CSA), CSC/hydroxypropyl-ß-CD (HP-ß-CD), as well as CSC/ß-CD (ß-CD), were evaluated for the first time for their enantioseparation capability by CE in this paper. During the course of the work, the influences of chiral selector concentration and buffer pH values on enantioseparation in dual systems were systematically investigated. Under the optimized conditions, the dual system consisting of CSC and glycogen exhibited better separations toward nefopam, duloxetine, sulconazole, atenolol, laudanosine, and cetirizine enantiomers compared to the single CSC or glycogen system. The combination of CSC and HP-ß-CD improved the separation of amlodipine and chlorphenamine enantiomers. However, no synergistic effect was observed in the CSC/CSA and CSC/ß-CD systems.

A new thiophene and two new monoterpenoids from Xanthium sibiricum.

Three new compounds (1-3), together with six known compounds (4-9), were isolated from the fruits of Xanthium sibiricum. The structures and the absolute configurations of sibiricumthionol (1), (+)-(5Z)-6-methyl-2-ethenyl-5-hepten-1,2,7-triol [(+)-2], ( - )-(5Z)-6-methyl-2-ethenyl-5-hepten-1,2,7-triol [( - )-2], (2E,4E,1'S, 2'R, 4'S, 6'R)-dihydrophaseic acid (3), (+)-xanthienopyran [(+)-4] and ( - )-xanthienopyran [( - )-4] were established by extensive spectroscopic analyses, X-ray crystallographic analysis, ECCD analysis and ECD calculations. Caffeic acid (7) and caffeic acid ethyl ester (8) weekly inhibited α-glucosidase enzymatic activity by 44.5% and 40.2%, respectively, at 40 µM. Protocatechuic acid (9) selectively exhibited cytotoxicity against HepG2 cell lines, with an IC50 value of 2.92 µM.

Selective removal of dibenzothiophene from commercial diesel using manganese dioxide-modified activated carbon: a kinetic study.

With a total concentration of 7055 mgS/kgfuel, the content of organosulphur compounds (OSCs) in local diesel is 20 times higher than the regulated value. Analysis revealed that 30% of OSC is originated from dibenzothiophene (DBT). It is known that DBT is a hardly removable compound and selective adsorbents are often needed for its removal with low affinity for other diesel components. In this work, a selective adsorbent based on surface modification of activated carbon (AC) by MnO2 is prepared for DBT removal from diesel. The porous nature of AC enabled carrying large amounts of MnO2 particles to end up with a selective adsorber for DBT. The best performance was observed at a surface loading of 26.8% of Mn and DBT is favourably removed over mono- and diaromatics hydrocarbons in diesel. Adsorption kinetics of DBT is studied under a high initial concentration of 835-11,890 mg/kg and at a ratio of 11 cm3/g (diesel:carbon). The results indicated a fast removal process after surface modification where 96% of the surface is occupied within 30 min of interaction. Kinetic data were best presented by reaction-based models with low prediction error sum of squares values 0.5-47.0, while, diffusion-based models showed limited application for modelling DBT adsorption. Accordingly, adsorption process is controlled by surface reactions and pore diffusion has a minor role in the overall process. The modified adsorbent is satisfactorily regenerated using n-hexane at 65°C.

Foetithiophenes C-F, thiophene derivatives from the roots of Ferula foetida.

CONTEXT: Ferula foetida Regel (Apiaceae) is an Iranian medicinal plant with various biological activities including antispasmodic and anthelmintic. OBJECTIVE: The sulfur compounds from the roots of F. foetida were isolated and characterized to test their cytotoxic and antimicrobial activities. MATERIALS AND METHODS: The methanolic extract of the roots of F. foetida was fractionated using silica column chromatography. The components of each fraction were further purified using RP-HPLC. Their structures were elucidated by 1- and 2-D NMR spectroscopy as well as HREIMS. Their cytotoxic and antimicrobial activities were evaluated using Alamar Blue assay and broth microdilution method, respectively. RESULTS: Four new thiophene derivatives, namely foetithiophenes C-F (3-6), together with four known compounds, foetithiophenes A (1) and B (2), coniferaldehyde, and sinapic aldehyde, were isolated from the roots of F. foetida. Antimicrobial activities were observed in particular against the Gram-positive bacteria. The best antimicrobial activity was observed for compound 6 against B. cereus with a MIC value 50 µg/mL. The tested compounds did not show cytotoxic properties against MCF-7 and K562 cells. CONCLUSION: Four new thiophene derivatives including foetithiophenes C-F (3-6) were characterized from the roots of F. foetida. Foetithiophene F (6) exhibited the most potent activity against the Gram-positive bacteria B. cereus.

Investigation on the enantioseparation of duloxetine by capillary electrophoresis, NMR, and mass spectrometry.

The enantiomeric separation of the antidepressant drug duloxetine was investigated by CE using 15 neutral CDs as chiral selectors. Among them, (2-hydroxypropyl)-ß-CD and methyl-γ-CD gave rise to the highest enantioresolution. The enantiomer migration order for duloxetine was found to be reversed depending on the CD employed: R-duloxetine was the first-migrating enantiomer for (2-hydroxypropyl)-ß-CD while it was the second-migrating enantiomer for methyl-γ-CD. NMR and MS experiments were performed in order to justify this behavior. Although the elucidation of the structure of the enantiomer-CD complexes was not possible, their averaged stoichiometry was studied and their apparent and averaged equilibrium constants were calculated. The results obtained showed that the chiral separation of duloxetine by CE depends not only on the thermodynamic stability of the enantiomer-chiral selector complexes but also on their electrophoretic mobility.

Thiophenes, polyacetylenes and terpenes from the aerial parts of Eclipata prostrate.

One new bithiophenes, 5-(but-3-yne-1,2-diol)-50-hydroxy-methyl-2,20-bithiophene (2), two new polyacetylenic glucosides, 3-O-b-D-glucopyranosyloxy-1-hydroxy-4E,6E-tetradecene-8,10,12-triyne (8), (5E)-trideca-1,5-dien-7,9,11-triyne-3,4-diol-4-O-b-D-glucopyranoside (9), six new terpenoid glycosides, rel-(1S,2S,3S,4R,6R)-1,6-epoxy-menthane-2,3-diol-3-O-b-D-glucopyranoside (10), rel-(1S,2S,3S,4R,6R)-3-O-(6-O-caffeoyl-b-D-glucopyranosyl)-1,6-epoxy menthane-2,3-diol (11), (2E,6E)-2,6,10-trimethyl-2,6,11-dodecatriene-1,10-diol-1-O-b-D-glucopyranoside (12), 3b,16b,29-trihydroxy oleanane-12-ene-3-O-b-D-glucopyranoside (13), 3,28-di-O-b-D-glucopyranosyl-3b,16b-dihydroxy oleanane-12-ene-28-oleanlic acid (14), 3-O-b-D-glucopyranosyl-(1?2)-b-D-glucopyranosyl oleanlic-18-ene acid-28-O-b-D-glucopyranoside (15), along with fifteen known compounds (1, 3­7, and 16­24), were isolated from the aerial parts of Eclipta prostrata. Their structures were established by analysis of the spectroscopic data. The isolated compounds 1­9 were tested for activities against dipeptidyl peptidase IV (DPP-IV), compound 7 showed significant antihyperglycemic activities by inhibitory effects on DPP-IV in human plasma in vitro, with IC50 value of 0.51 lM. Compounds 10­24 were tested in vitro against NF-jB-luc 293 cell line induced by LPS. Compounds 12, 15, 16, 19, 21, and 23 exhibited moderate anti-inflammatory activities.

Biodesulfurization of dibenzothiophene and gas oil using a bioreactor containing a catalytic bed with Rhodococcus rhodochrous immobilized on silica.

Biodesulfurization (BDS) in a bioreactor packed with a catalytic bed of silica containing immobilized Rhodococcus rhodochrous was studied. Various bed lengths and support particle sizes were evaluated for BDS of dibenzothiophene (DBT) and gas oil. The sulfur-containing substrates were introduced separately into the bioreactor at different feed flows. Higher removal of sulfur from DBT and gas oil was achieved with a long bed, lower substrate flow, and larger sizes of immobilization particles. The packed bed bioreactor containing metabolic active cells was recycled and maintained BDS activity.

Acyclic sulfides, garlicnins L-1-L-4, E, and F, from Allium sativum.

Six novel acyclic sulfides, named garlicnins L-1-L-4 (1-4), E (5), and F (6), were isolated from the acetone extracts, with the ability to suppress M2 macrophage activation, of the bulbs of garlic (Allium sativum L.), and their chemical structures were characterized.

Isolation and characterization of new onionins A2 and A3 from Allium cepa, and of onionins A1, A2, and A3 from Allium fistulosum.

In this study, the new stable sulfur-containing compounds onionins A2 (1) and A3 (2) were isolated from the acetone extracts of the bulbs of Allium cepa L. and identified as the stereoisomers of onionin A1 discovered in our previous study. Their chemical structures, 3,4-dimethyl-5-(1E-propenyl)-tetrahydrothiophene-2-sulfenic acid-S-oxides, were characterized using various spectroscopic techniques. In addition, 1 and 2 together with onionin A1 were successfully isolated from the leaves of the Welsh onion, Allium fistulosum L. The onion-extracted fractions showed good potential to inhibit the polarization of M2 activated macrophages, indicating their possible ability to inhibit tumor cell proliferation.

Toxicity of thiophenes from Echinops transiliensis (Asteraceae) against Aedes aegypti (Diptera: Culicidae) larvae.

Structureactivity relationships of nine thiophenes, 2,2': 5',2″-terthiophene (1), 2-chloro-4-[5-(penta-1,3-diyn-1-yl)thiophen-2-yl]but-3-yn-1-yl acetate (2), 4-(2,2'-bithiophen-5-yl)but-3-yne-1,2-diyl diacetate (3), 4-[5-(penta-1,3-diyn-1-yl)thiophen-2-yl]but-3-yne-1,2-diyl diacetate (4), 4-(2,2'-bithiophen-5-yl)-2-hydroxybut-3-yn-1-yl acetate (5), 2-hydroxy-4-[5-(penta-1,3-diyn-1-yl)thiophen-2-yl]but-3-yn-1-yl acetate (6), 1-hydroxy-4-[5-(penta-1,3-diyn-1-yl)thiophen-2-yl]but-3-yn-2-yl acetate (7), 4-(2,2'-bithiophen-5-yl)but-3-yne-1,2-diol (8), and 4-[5-(penta-1,3-diyn-1-yl)thiophen-2-yl]but-3-yne-1,2-diol (9), isolated from the roots of Echinops transiliensis, were studied as larvicides against Aedes aegypti. Structural differences among compounds 3, 5, and 8 consisted in differing AcO and OH groups attached to C(3″) and C(4″), and resulted in variations in efficacy. Terthiophene 1 showed the highest activity (LC50 , 0.16 µg/ml) among compounds 1-9, followed by bithiophene compounds 3 (LC50 , 4.22 µg/ml), 5 (LC50 , 7.45 µg/ml), and 8 (LC50 , 9.89 µg/ml), and monothiophene compounds 9 (LC50 , 12.45 µg/ml), 2 (LC50 , 14.71 µg/ml), 4 (LC50 , 17.95 µg/ml), 6 (LC50 , 18.55 µg/ml), and 7 (LC50 , 19.97 µg/ml). These data indicated that A. aegypti larvicidal activities of thiophenes increase with increasing number of thiophene rings, and the most important active site in the structure of thiophenes could be the tetrahydro-thiophene moiety. In bithiophenes, 3, 5, and 8, A. aegypti larvicidal activity increased with increasing number of AcO groups attached to C(3″) or C(4″), indicating that AcO groups may play an important role in the larvicidal activity.