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The main purpose of this study was to compare the antioxidant and anticancer activities of lycopene samples with different ratios of Z-isomers. Lycopene samples containing 5%, 30%, and 55% Z-isomers were successfully prepared by using thermal treatment combined with anti-solvent crystallization. The in vitro bio-accessibility of lycopene was estimated by the determination of partition factor (PF) and the results showed that lycopene with 55% Z-isomers possessed the highest bio-accessibility. Moreover, DPPH and ABTS assays suggested that the antioxidant activity of lycopene increased with the Z-isomers content from 5% to 55%. However, lycopene inhibited the survival of human hepatocellular carcinoma cells (HepG2) in a dose and time-dependent manner. The highest inhibition of HepG2 cell lines was achieved by 55% Z-ratio of lycopene. The cell viability was 22.54% at 20 μg/mL after incubating for 24 h, the number of cells was significantly reduced and the morphology was shrunk. Furthermore, molecular docking was introduced to compare the binding ability between different lycopene isomers with Scavenger Receptor class B type I (SR-BI), and the results revealed that the affinity of (all-E)-lycopene with SR-BI was lower compared to 5Z-lycopene and 13Z-lycopene, providing the reasons for different bioavailability of the above-mentioned lycopene isomers. All the above results demonstrated that Z-isomers-rich lycopene could enhance bio-accessibility and biological functionality.

The derivatives of isatin have already been known to display a variety of biological activities. Therefore, the studies on their activity and its relation to structure have recently become a popular subject for investigation. The examined compounds were synthesized by the reaction of isatin and substituted primary amines and characterized by spectroscopic methods. The investigation of the antimicrobial and antioxidative activity of the synthesized compounds was performed by broth microdilution method. As for the characterization of the investigated isatin based Schiff bases, the linear solvation energy relationships (LSER) were used to analyze the solvent influence on the UV absorption maxima shifts (max), using the well known Kamlet–Taft model and taking geometrical isomers into consideration when possible. Linear free energy relationships (LFER) were used to analyze substituent effect on pKa, as well as NMR chemical shifts and max values. The antimicrobial activity and characterization were related using both experimental and theoretical methods. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172013]

By using iodine-catalyzed photoisomerization, and HPLC-DAD, we found that were: in the spectrum of each carotene there is a “far UV peak”, which maintains the maximum in all its E/Z isomers and this maximum it is different from E/Z isomers of other carotene. The values of these absorption maxima 294–296 nm for lycopene E/Z isomers; 266–269 nm for α-carotene E/Z isomers; 273–276 nm for β-carotene E/Z isomers; 281–283 nm for γ-carotene E/Z isomers; and 280–282 nm for γ-carotene E/Z isomers. These UV absorption peaks are highly valuable to determine which components are geometrical isomers of the same carotene, since that not only the maximum absorbance is specific for each carotene, but also the shapes of these peaks are clearly different. The utility of this “far UV peak” was tested, by identifying Z isomers in Bactris gasipaes fruit. We found that two carotenoids previously identified as all- E -δ-carotene and Z -γ-carotene, are actually Z -γ-carotene and Z -lycopene respectively. [ABSTRACT FROM AUTHOR]

The Z and E isomers of 3-[4-(dimethylamino)phenyl]-2-(2,4,6-tribromophenyl)acrylonitrile, C17H13Br3N2, ( 1), were obtained simultaneously by a Knoevenagel condensation between 4-(dimethylamino)benzaldehyde and 2-(2,4,6-tribromophenyl)acetonitrile, and were investigated by X-ray diffraction and density functional theory (DFT) quantum-chemical calculations. The ( Z)-( 1) isomer is monoclinic (space group P21/ n, Z′ = 1), whereas the ( E)-( 1) isomer is triclinic (space group P, Z′ = 2). The two crystallographically-independent molecules of ( E)-( 1) adopt similar geometries. The corresponding bond lengths and angles in the two isomers of ( 1) are very similar. The difference in the calculated total energies of isolated molecules of ( Z)-( 1) and ( E)-( 1) with DFT-optimized geometries is ∼4.47 kJ mol−1, with the minimum value corresponding to the Z isomer. The crystal structure of ( Z)-( 1) reveals strong intermolecular nonvalent Br...N [3.100 (2) and 3.216 (3) Å] interactions which link the molecules into layers parallel to (10). In contrast, molecules of ( E)-( 1) in the crystal are bound to each other by strong nonvalent Br...Br [3.5556 (10) Å] and weak Br...N [3.433 (4) Å] interactions, forming chains propagating along [110]. The crystal packing of ( Z)-( 1) is denser than that of ( E)-( 1), implying that the crystal structure realized for ( Z)-( 1) is more stable than that for ( E)-( 1). [ABSTRACT FROM AUTHOR]

The primary purpose of this work was to demonstrate the suitability of circular dichroism (CD) spectroscopy in stereochemical studies of α,β-unsaturated oximes, with particular emphasis on determination of E and Z geometry of the oxime double bond. As models for this study, O-phenyl and O-triphenylmethyl (trityl) oximes of 4-hydroxy-2-methylcyclopent-2-en-1-one were selected. These model compounds differ in both absolute configuration at C4 carbon atom and E- Z configuration of the oxime double bond. The basic dichroic technique applied was electronic circular dichroism (ECD) assisted by quantum-chemical calculations and vibrational circular dichroism (VCD) for selected cases. Such an approach enabled effective implementation of both goals. Thus, we were able to associate the signs of Cotton effects in the range of 190-240 nm with the absolute configuration at C4 and within 240-300 nm with the E- or Z-geometry of the oxime double bond. Within this work, optical activity of the protecting trityl group was also studied towards formation of the propeller-shaped conformations by using the same combined CD/DFT methodology. As shown, the helical structure of the trityl group has a considerable influence on the ECD spectra. However, the MPM and PMP conformers of the trityl group are in fact almost equally populated in the conformational equilibrium, making it impossible to distinguish them. On the other hand, rotamers of the hydroxyl group at C4 show a decisive impact on the VCD spectra in both phenoxy and trityl oximes. [ABSTRACT FROM AUTHOR]

Abstract: Amidines, the nitrogen analogues of carboxylic acids, show interesting roles as pharmacophore groups in biologically active agents and in compounds of pharmaceutical interest. In the last years, our research group disclosed inhibitors of inducible and neuronal Nitric Oxide Synthase (iNOS and nNOS, respectively) containing the amidino moiety, with the aim to extend the study of the possible ligand‐enzyme interactions. Here we discuss the synthesis and spectral studies of acetamidino derivative N‐(2‐(pyrrolidin‐1‐yl)ethyl)acetimidamidinium bromide, and how these studies led us to identification of a E/Z configurational change, which could be helpful in elucidating the ligand‐enzyme interactions. [ABSTRACT FROM AUTHOR]

New acyl hydrazones were synthesized by condensation with camphorquinone aiming at extending the range of applications of the biologically active camphor compounds and structural studies by XRD, 1 H-NMR and IR were used in conjunction with advanced computational methodologies to understand the new structural chemistry enabled by the conjugation of the camphor ketone group to the hydrazone N C double bond. In particular, were analysed supramolecular arrangements either by hydrogen bonding to water molecules or electrostatic interactions with non protic solvents. The relative stability of all conformers ( E / Z ) prompted by the hydrazone bond was addressed by state of the art methods such as CR-CCSD(T) and their inter-conversion in both S 0 and S 1 by CR-EOM-CCSD(T). [ABSTRACT FROM AUTHOR]

Abstract: Twenty-three new oxime ester derivatives of nafimidone were synthesized with the prospect of potential anticonvulsant activities. MES and ScM tests were employed for their anticonvulsant activities and rotorod test for neurological deficits. Eighteen compounds were found to be protective against MES seizures. Alkyl (1–8) and arylalkyl (9, 10) oxime ester derivatives were found to be more active than aryl oxime ester derivatives (11–23). Five compounds (2, 3, 7, 9, 10), which were protective at 0.5 h at the doses of 30 mg/kg and higher in MES test, showed the highest activity. Compound 17 was the most active one in ScM test at all dose levels at 4 h. [Copyright &y& Elsevier]

A convergent, general synthetic route to 17-membered macrocycles was developed to support biological evaluation and structure–activity relationship (SAR) studies during phenotypic screening for immunology targets. A series of amide coupling reactions led to a ring-closing metathesis (RCM) precursor that was cyclized using Grubbs' catalysts. It was found that the reaction formed the macrocyclic products in a 3:1 ratio of E/Z isomers. Moreover, it was shown that a number of similarly substituted RCM precursors undergo cyclization to produce the geometric E/Z isomers in roughly the same 3:1 ratio. The remarkable independence of the E/Z outcome from the substitution pattern of the RCM precursor makes this synthetic approach generally applicable. Separation of the E/Z isomers was achieved by preparative high-performance liquid chromatography and allowed biological profiling of the geometric isomers. Reactive groups in the macrocycle were utilized for late-stage modifications in the fashion of diversity-orientated synthesis (DOS), yielding analogs for SAR studies. [ABSTRACT FROM AUTHOR]

Abstract: About 90–98% of native lycopene exists in the all-E form, but 79–88% of the lycopene found in the human body are Z-isomeric forms. Thermally-induced geometrical isomerisation of lycopene occurred within 24h of refluxing in ethyl acetate and the proportion of Z-isomers increased from 5.8% to 49.9%. Accordingly, the concentration of lycopene required to double quinone reductase (QR) activity in Hepa 1c1c7 cells decreased from >100 to ∼22μg/mL following thermo-isomerisation, while cell viability was retained at >87% at levels up to 50μg/mL. The inhibition of nitric oxide (NO) production in activated RAW 264.7 macrophages was 50% at ∼100μg/mL thermo-isomerised lycopene and increased to >80% when the concentration in the medium was increased to 500μg/mL. No significant inhibition of NO evolution by macrophages occurred with native (∼94% all-E) lycopene. Both QR induction and NO inhibition bioassays revealed that the structural changes evoked by thermo-isomerisation were accompanied by enhanced biological functionality. [Copyright &y& Elsevier]

Abstract: The present study examines the influence of N-heterocyclic carbene (NHC) ligand electronic and steric parameters on the activity of ruthenium indenylidene complexes in cross metathesis. The NHC ligands tested lead to varied E/Z selectivities with the pre-catalyst bearing an IMes ligand exhibiting high activity. [Copyright &y& Elsevier]

• Manuscript is research article. In this study, 12 oxime derivatives were synthesized by using with conventional method and microwave irradiation method. It was aimed to compare the effectiveness of the conventional method and microwave method. Their yields were determined for both methods, and the yields increased when the microwave method was used. The compounds which have oxime show geometric isomerism because they have carbon-nitrogen double bonds. Therefore, we have also aimed to evaluate their E / Z isomer ratios in this study. While the synthesized pyrazole derivative compounds were mostly obtained in Z isomer in both synthesis methods, it was observed that some of the title compounds were almost completely obtained as E isomers when the conventional synthesis method was used in the synthesized imidazole derivative compounds. The structures of synthesized compounds were confirmed by IR, 1 H -NMR, 13 C -NMR and HRMS spectra. Additionally, in this study, the HOMO-LUMO energies and thermodynamic properties of the E/Z isomers of 12 oxime derivatives were performed using the 6-31 * G basis set and the Density Functional Theory (DFT) calculation using the B3LYP method three different environments (water, ethanol, vacuum). In addition, geometric parameters such as chemical hardness (η), chemical potential (µ), electrophilicity index (ω) , chemical softness (σ) were calculated depending on the calculated HOMO-LUMO energies. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Research on the biosynthesis of carotenoid pigments, from diverse points of view, has undergone a considerable boost in recent years due to the large body of studies that highlights their beneficial effects in humans. To obtain valuable information from such surveys, it is of paramount importance to reduce the tentativeness with which some carotenoids are still identified, above all, when they are key compounds for the synthesis of other important metabolites. This is the case for neoxanthin (5′,6′-epoxy-6,7-didehydro-5,6,5′,6′-tetrahydro-β,β-carotene-3,5,3′-triol), an epoxycarotenoid which can be found in the light harvesting apparatus of plants and whose cleavage leads to the formation of xanthoxin and then of the plant hormone abscisic acid, among other compounds. Hence, this paper presents pieces of evidence that may put in doubt the presence of such a carotenoid in orange juice, as a consequence of which we propose that the compound formerly tentatively identified as neoxanthin should be referred to as “unidentified” prior to its conclusive characterization and identification. [Copyright &y& Elsevier]

Abstract: On photooxygenation (methylene blue as sensitizer) of E/Z enecarbamates, equipped with the oxazolidinone chiral auxiliary, the oxidative cleavage of the alkenyl functionality releases the enantiomerically enriched methyldesoxybenzoin (MDB) product. The extent (% ee) as well as the sense (R vs S) of the stereoselectivity in the MDB formation depends on the choice of the alkene configuration; the efficacy of stereocontrol may be tuned by appropriate solvent and temperature conditions. Highlighted is the finding that the formation of the preferred MDB enantiomer (R or S) depends for the E isomer on the chosen solvent and temperature, but not for the corresponding Z isomer. The activation parameters for the various solvents disclose that differential entropy effects (ΔΔS ‡) dominate the conformationally more flexible E diastereomers. As mechanistic rationale for this unprecedented conformationally imposed stereochemical behavior, we propose the competitive action of stereoselective vibrational quenching of the attacking singlet oxygen by the enecarbamate versus sterically controlled stereoselective oxidative cleavage of its double bond. [Copyright &y& Elsevier]

Configuration-controllable E/Z isomers based on tetraphenylethene were prepared with a facile and effective method. First, compounds 1 and 2, configuration-controllable precursors of E/Z isomers, were synthesized. Then, pure E/Z isomers were obtained via Suzuki reaction, avoiding the difficulties of separation. The conformational changes of E/Z isomers can occur through photoactivation. Importantly, red-shifts of 66 nm from 6 (E-) to 3 (Z-) and 58 nm from 7 (E-) to 4 (Z-) were observed remarkably on the photoluminescence (PL) emission spectra. The Z isomer showed a longer fluorescence lifetime compared with the E isomer. The Z isomers 3 and 4 exhibited piezofluorochromism under grinding, whereas the E isomers 6 and 7 showed no such behaviors. The E isomer has better thermal stability than the Z isomer. Lastly, graphene-like molecules were synthesized with the FeCl 3 /CH 3 NO 2 system. The E and Z isomers after oxidation showed negligible differences in the PL emission spectra because the effective conjugated lengths of oxidized E and Z isomers were both extended. Furthermore, the fabricated field-effect transistors showed nice performance with mobilities of 0.92 and 1.14 cm -2 V -1 s -1 at low operating voltages, respectively.

The ratios of E/Z isomers of sixteen synthesized 1,3-dihydro-3-(substituted phenylimino)-2H-indol-2-one were studied using experimental and theoretical methodology. Linear solvation energy relationships (LSER) rationalized solvent influence of the solvent-solute interactions on the UV-Vis absorption maxima shifts (ν max ) of both geometrical isomers using the Kamlet-Taft equation. Linear free energy relationships (LFER) in the form of single substituent parameter equation (SSP) was used to analyze substituent effect on pK a , NMR chemical shifts and ν max values. Electron charge density was obtained by the use of Quantum Theory of Atoms in Molecules, i.e. Bader's analysis. The substituent and solvent effect on intramolecular charge transfer (ICT) were interpreted with the aid of time-dependent density functional (TD-DFT) method. Additionally, the results of TD-DFT calculations quantified the efficiency of ICT from the calculated charge-transfer distance (D CT ) and amount of transferred charge (Q CT ). The antimicrobial activity was evaluated using broth microdilution method. 3D QSAR modeling was used to demonstrate the influence of substituents effect as well as molecule geometry on antimicrobial activity., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Two new ether substituted azodyes were synthesized and characterized by different spectral analysis such as (1)H NMR, (13)C NMR, FTIR and UV/Vis. Synthesized compounds were used to study the photoisomerization phenomenon by using UV-Vis spectro-photometer. Interesting polarity dependent effect is observed for the first time on these materials. Trans-cis (E-Z) and cis-trans (Z-E) conversion occurred within 41 s and 445 min, respectively for both the compounds in solutions. Polarizing optical microscopy studies revealed that there is no liquid crystal phase for both the compounds. The dramatic variation in the optical property is speculated to be the polarity of the chemical species. These derivatives are useful to fabricate optical data storage devices., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A reverse phase high performance liquid chromatography (HPLC) method has been developed for the separation of two geometric isomers of Acrivastine using crude reaction mixture. The resolution between two isomers was found more than 2.9. The geometric isomers have been isolated by preparative HPLC and characterized by spectroscopic techniques, such as NMR, infrared, and MS. The developed method has been validated for the determination of Z-isomer in Acrivastine. The limit of detection and limit of quantification of the Z-isomer were 0.05 and 0.2 μg/ml, respectively. The developed method is precise, linear, accurate, rugged and robust for its intended use., (Copyright © 2011 Wiley-Liss, Inc.)