Title Species Research Articles

Sesquiterpenoids and steroids from Eupatorium fortunei and their inhibitory effects on NO production

Two heterodimers including a clovane-phenylpropanoid hybrid (1) and a clovane-menthane hybrid (2), five linear sesquiterpenoids incorporating a tetrahydrofuran ring (3–6 & 8), and four steroids (7 & 9–11), were separated from the ethanolic extract of a well-known aromatic and medicinal herb Eupatorium fortunei. Their structures were characterised by detailed analyses of spectroscopic data and comparison with known analogues, with seven (1–7) of them being described for the first time. The hybrids 1 and 2 represent the first examples of clovane type sesquiterpenoids hybridising with other class of natural products, and compounds 3–6 and 8 are first linear sesquiterpenyl constituents reported from the title species. All the isolates were evaluated for their inhibitory effect on the NO production induced by LPS in murine RAW264.7 macrophage cells, and 1, 7, 10 and 11 exhibited moderate activity with IC50 values in the range of 24.4–43.5 µM.

Oxygenated Cembrane Diterpenes from the South China Sea Soft Coral Sinularia tumulosa.

The chemical investigation of the rarely studied soft coral Sinularia tumulosa resulted in the discovery of five oxygenated cembrane diterpenes 1-5, including two new compounds situmulins A (1) and B (2). The structures of 1 and 2 were established through the extensive analyses of 1D and 2D NMR spectral data together with the comparisons with the known compounds. Furthermore, the absolute configuration of 1 was determined by the time-dependent density functional theory (TDDFT) ECD approach, while the relative configuration of 2 was assigned via the quantum mechanical-NMR (QM-NMR) calculations. It might be worth to point out it is the first time to disclose the presence of cembrane diterpenes in the title species. In the bioassays, compound 2 not only showed strong antibacterial activities against fish pathogenic bacteria Streptococcus parauberis FP KSP28 and Phoyobacterium damselae FP2244 with both minimum inhibitory concentration for 90 % (MIC90 ) values of 25 μM, but also demonstrated substantial inhibitory efficacy against vancomycin-resistant Enterococcus faecium bacteria G1, G4, G7, G8 and G13 from several individuals, with MIC90 values of 25, 50, 100, 50 and 25 μM, respectively.

Computer-Aided Drug Design and Synthesis of Rhenium Clotrimazole Antimicrobial Agents.

In the context of the global health issue caused by the growing occurrence of antimicrobial resistance (AMR), the need for novel antimicrobial agents is becoming alarming. Inorganic and organometallic complexes represent a relatively untapped source of antibiotics. Here, we report a computer-aided drug design (CADD) based on a 'scaffold-hopping' approach for the synthesis and antibacterial evaluation of fac-Re(I) tricarbonyl complexes bearing clotrimazole (ctz) as a monodentate ligand. The prepared molecules were selected following a pre-screening in silico analysis according to modification of the 2,2'-bipyridine (bpy) ligand in the coordination sphere of the complexes. CADD pointed to chiral 4,5-pinene and 5,6-pinene bipyridine derivatives as the most promising candidates. The corresponding complexes were synthesized, tested toward methicillin-sensitive and -resistant S. aureus strains, and the obtained results evaluated with regard to their binding affinity with a homology model of the S. aureus MurG enzyme. Overall, the title species revealed very similar minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values as those of the reference compound used as the scaffold in our approach. The obtained docking scores advocate the viability of 'scaffold-hopping' for de novo design, a potential strategy for more cost- and time-efficient discovery of new antibiotics.

Collision-induced state-changing rate coefficients for cyanogen backbones NCN 3Σ- and CNN 3Σ- in astrophysical environments.

We report quantum calculations involving the dynamics of rotational energy-transfer processes, by collision with He atoms in interstellar environments, of the title molecular species which share the presence of the CN backbone and are considered of importance in those environments. The latter structural feature is taken to be especially relevant for prebiotic chemistry and for its possible role in the processing of the heterocyclic rings of RNA and DNA nucleobases in the interstellar space. We carry out ab initio calculations of their interaction potentials with He atoms and further obtain the state-to-state rotationally inelastic cross sections and rate coefficients over the relevant range of temperatures. The similarities and differences between such species and other similar partners which have been already detected are analyzed and discussed for their significance on internal state populations in interstellar space for the two title molecular radicals.

Identification of Small-Molecule Bioactive Constituents from the Leaves of Vaccinium bracteatum Confirms It as a Potential Functional Food with Health Benefits

The health benefits of Vaccinium bracteatum are well recorded in ancient Chinese medical books and were also demonstrated by modern researches. However, the relationship between its beneficial functions and specific chemical constituents has not been fully characterized. This study investigated the bioactive small-molecule constituents in the leaves of V. bracteatum, which afforded 32 compounds including ten new ones (1-9) and ten pairs of enantiomers (9-18). Their structures with absolute configurations were elucidated by spectroscopic methods, especially nuclear magnetic resonance (NMR) and electronic circular dichroism (ECD) analyses, with 1-4 bearing a novel revolving-door shaped scaffold. While half-compounds exhibited decent antioxidant activity by scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, all except 19 and 20 exerted significant capturing activity against diammonium 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radicals. In addition, the new iridoids 1, 5, 6, and 7 exerted apparent neuroprotective activity toward PC12 cells, with 1 being comparable to the positive control, and selective compounds also displayed anti-diabetic and anti-inflammatory properties by inhibiting α-glucosidase and NO production, respectively. The current work revealed that the bioactive small-molecule constituents could be closely related to the functional food property of the title species.

Isolation, Structure Characterization, Total Synthesis and Biological Evaluation of Cinnamic Acid Derivatives from Tinospora sagittata.

Thirteen cinnamic acid derivatives (1-13), including six formerly unreported hybrids incorporating different short-chain fatty acid esters (1-6), have been obtained and structurally elucidated from an ethnological herb Tinospora sagittata. The structures of them have been established by spectroscopic data analyses and NMR comparison with known analogs, while those of 1, 2, 4 and 6 have been further supported by total synthesis, and it is the first report of this type of metabolites from the title species. All the isolates have been assessed in an array of bioassays encompassing cytotoxic, antibacterial, anti-inflammatory, antioxidant, as well as α-glucosidase and HDAC1 inhibitory models. Compound 7 showed significant inhibitory activity against α-glucosidase, and half of the isolates also displayed moderate antiradical effect.

Electronic structure of the ground and excited states of neutral and charged silicon hydrides, SiHx0/+/−, x = 1–4

The ground and excited electronic states of the titled species are investigated with multi-reference configuration interaction and diffuse basis sets. We found that in addition to the valence orbitals, the inclusion of the 4s, 4p, and especially 3d orbitals (although with minimal population) of silicon in the active space of the reference complete active space self-consistent field wavefunction are necessary for the proper convergence of the calculations. We also demonstrate that the aug-cc-pVTZ basis set provides quite accurate results compared to both larger basis sets and basis set limit results at a lower computational cost. The excited states involve excitations within the 3s and 3p orbitals of silicon (especially for the mono- and di-hydrides), followed by excitations from the Si-H bonding orbitals to either silicon valence or Rydberg (4s, 4p) orbitals. The number of electronic states per energy unit decrease as we add hydrogen atoms, and the first excited state of SiH4 is at 9.0 eV and leads to SiH3 + H. All species have stable ground state structures with all hydrogen atoms bound to silicon, except for SiH4+ and SiH4-. The former dissociates to SiH2+ + H2, while the latter loses an electron or can dissociate forming H2 as well.

Anti-inflammatory and analgesic monoterpenoid indole alkaloids of Kopsia officinalis

Ethnopharmacological relevance“Ya gai”, an important part of Dai medical theory, is traditionally recognized as an antidote. Kopsia officinalis Tsiang et P. T. Li is a “Ya gai” related medicine and has been widely used by Dai people for the treatment of pain and inflammation. Previous literature on title species suggested that monoterpenoid indole alkaloids (MIAs) could be its main bioactive components. However, the specific bioactive ingredients for inflammation-related treatment are still unrevealed, which inspired us to conduct a phytochemical and pharmacological investigation related to its traditional use. Aim of the studyTo support the traditional use of K. officinalis by assessing the anti-inflammatory and analgesic effects of its purified MIAs. Material and methodsCompounds were isolated and purified from the barks and leaves of K. officinalis using diverse chromatographic methods. The structures were established by means of extensive spectroscopic analyses and quantum computational technique. The anti-inflammatory activities of the purified MIAs were evaluated in vitro based on the suppression of lipopolysaccharide-activated inflammatory mediators (COX-2, IL-1β, and TNF-α) in RAW 264.7 macrophage cells. Anti-inflammatory and analgesic activities in vivo were assessed with carrageenan-induced paw edema and acetic acid-stimulated writhing in mice models. Results23 MIAs including four new compounds were obtained and structurally established. Most of isolates showed significant anti-inflammatory effects in vitro by inhibiting inflammatory mediators (COX-2, IL-1β, and TNF-α). Further pharmacological evaluation in vivo revealed that 12-hydroxy-19(R)-hydroxy-ibophyllidine (1) and 11,12-methylenedioxykopsinaline N4-oxide (5) remarkably decreased the number of writhing, while kopsinic acid (8), (−)-kopsinilam (12), and normavacurine-21-one (20) significantly relieved paw edema, respectively, even better than the positive control aspirin. ConclusionsThe in vitro and in vivo findings supported the traditional use of K. officinalis with respect to its anti-inflammatory and analgesic effect, as well as provided potent bioactive MIAs for further chemical modification and pharmacological investigation.

Ethnobotanical, phytochemical and pharmacological aspects of Bengal Pogostemon (Pogostemon benghalensis)

Pogostemon benghalensis (Burm.f.) Kuntze (Lamiaceae) is an important aromatic plant. Multiple classes of phytochemicals such as flavonoids, phenols, phytosteroids, carbohydrates, fatty acids, glycosides, sterols, terpenoids, tannins, essential oil, and alkaloids have been isolated from the title species. Different plant parts have been used as traditional remedies for various ailments. The present review aims to update and coherent the fragmented information on botanical aspects, phytochemistry, traditional uses, and pharmacological activities. An extensive review of the literature was carried out by using various search engines like PubMed, Scopus, Science Direct, Google Scholar, Google, Scifinder for information. The articles were searched using the keywords "Pogostemon", "Parviflorus’, "benghalensis". Chemical structures of the chemical compounds were drawn using software Chem Draw ultra 8.0. Most of the plant parts have been used for the treatment of various ailments. Phytochemistry reveals that the plant is a rich source of various biologically active compounds. Pogostemon extracts exhibited numerous pharmacological effects like anticancer, anti-inflammatory, antimicrobial and antioxidant activities. In sum, P. benghalensis is a promising aromatic and medicinal plant as depicted by its various traditional uses and pharmacological studies. Bioactive compounds, responsible for its various pharmacological activities at the molecular level, need further detailed investigations. Future clinical studies are also required to validate the various traditional uses of P. benghalensis.

Spontaneous Reductive Elimination at Iridium(III) Induced by the Strong π‐Acceptor Ligand Trifluorophosphane

The reaction of the cyclometalated five‐coordinate 16 VE iridium(III) compound [IrCl(H)(P(tBu)2C6H4‐κ2P,C)(P(tBu)2Ph)] (1) with the strong π‐acceptor ligand trifluorophosphane resulted quickly in the quantitative formation of the new iridium(I) complex trans‐[IrCl(PF3)(P(tBu)2Ph)2] (2). This unexpected spontaneous reductive elimination was already observed in reactions of 1 with the very strong π‐acceptor ligands CO and NO+. First indications during reactions of 1 with lesser strong π‐acceptor ligands like alkyl or arylphosphanes did not show this inversion behavior of the cyclometalation. The title species 2 was characterized by spectroscopic methods and its molecular structure in the crystal was confirmed by X‐ray crystallography.

Theoretical investigation of protonated thiophene and two of its nitrile substituted derivatives (2-cyanothiophene and 3-cyanothiophene).

Theoretical and experimental spectroscopic data for protonated cyano-thiophenes (R-CNH+ with R = C4H3S), which are needed for their interstellar search and/or detection, are still lacking in the literature. Considering the high abundance and reactivity of H3+ in the interstellar medium (ISM), a quantum chemical investigation on protonated thiophene and two of its nitrile-substituted derivatives (2-cyanothiophene and 3-cyanothiophene) is undertaken for their characterization. The geometrical structures for the title species are calculated at the M06-2X/6-31G(d,p) level of theory, followed by an empirical correction for systematic errors. At the same level of theory, IR and Raman spectra are explored and the rotational parameters are calculated. The proton affinity (PA) of R-CN and the enthalpy, entropy and Gibbs free energy changes (ΔrH, ΔrS and ΔrG) of the reactions producing R-CNH+ are computed at the G2(MP2) and G3B3 levels of theory and at different temperatures. The PA calculations show that the protonation favors the nitrogen atom, while ΔrH, ΔrS, and ΔrG reveal the spontaneous reactions producing R-CNH+ and their neutral forms. In addition, quadrupole hyperfine structures are predicted, while the region where the brightest lines fall at different temperatures is discussed. These results are expected to assist astrophysicists and astrochemists in the search for new species in the ISM.

Equilibrium Structures of the Phosphorus Trihalides PF3 and PCl3, and the Phosphoranes PH3F2, PF5, PCl3F2, and PCl5.

Among the title species, a reliable and accurate equilibrium geometry (re structure) is available only for PF3, which has been determined experimentally more than 20 years ago. Here, we report accurate re structures for all title molecules, which were obtained using a composite computational approach based on explicitly correlated coupled-cluster theory (CCSD(T)-F12b) in conjunction with a large correlation-consistent basis set (cc-pCVQZ-F12) to take core–valence electron correlation into account. Additional terms were included to correct for the effects of iterative triple excitations (CCSDT), noniterative quadruple excitations (CCSDT(Q)), and scalar relativistic contributions (DKH2-CCSD(T)). The performance of this computational procedure was established through test calculations on selected small molecules (PH, PF, PCl, PH2, PF2, and PH3). For PF3, PCl3, PH3F2, and PF5 sufficiently accurate experimental ground-state rotational constants from the literature were used to determine semiexperimental re structures, which were found to be in excellent agreement with the corresponding best estimates from the current composite approach. The recommended equilibrium structural parameters are for PCl3, re(PCl) = 203.94 pm and θe(ClPCl) = 100.18°; for PH3F2, re(PHeq) = 138.38 pm and re(PFax) = 164.15 pm; for PF5, re(PFeq) = 153.10 pm and re(PFax) = 157.14 pm; for PCl3F2, re(PCleq) = 200.21 pm and re(PFax) = 159.37 pm; and for PCl5, re(PCleq) = 201.29 pm and re(PClax) = 211.83 pm. The associated uncertainties are estimated to be ±0.10 pm and ±0.10°, respectively.

How to Effectively Enhance Sustainable Livelihoods in Smallholder Systems: A Comparative Study from Western Kenya

Increasing communities’ adaptive capacity is crucial to enhancing the sustainability of livelihoods and landscapes in smallholder systems. This study evaluates the contributions of an asset-based community-driven local development project, which has an objective to enhance farmer livelihoods through context-specific agricultural and agroforestry training, in line with farmers’ identities, interests, and preferences. The project was implemented in two areas of the wider Nyando river basin: the Lower and Middle Nyando sites. The project effects on farmer livelihoods were evaluated by analyzing overall income enhancement through the adoption of climate-smart agricultural practices via the computation of total values of harvest. Socioeconomic data from 183 households, half of which were involved in the project, were considered. The findings showed that locality played an important role in the adoption and success of good agricultural practices. Additional significant positive factors included project participation, size of land operated, horticulture farming, livestock ownership, ownership of a title deed, hours worked, and crop species richness. The number of years farmed had a significant negative correlation with the value of harvest. Considering the stark differences in livelihood effects in both sites, researchers conclude that external support for climate-smart agriculture uptake needs to be considerate of, and respond to, biophysical and socioeconomic context.

Colorimetric fluorescence probe detecting Hg2+ and OCl– based on intramolecular charge transfer and excited-state intramolecular proton transfer mechanisms

The recognition and detection of Hg2+ and OCl– have been subjected to extensively attention, since these ions can cause extremely adverse effects on living body. Recently, a novel fluorescence probe molecule simultaneously detecting Hg2+ and OCl– ions had been researched in experiment, while a carefully molecular-level theoretical investigation was lacking. In this work, the photochemical and photophysical processes in excited state were researched for title species, the corresponding sensing mechanism was reported detailedly for the first time. The computational data of absorption and emission spectra agreed well with experimental results. The calculated hydrogen bond parameters and the visualized reduced density gradient isosurfaces indicated that the strengthening hydrogen bond in excited state facilitated the occurrence of the excited-state intramolecular proton transfer (ESIPT) reactions. The fluorescence signal that detected Hg2+ ion was also reassigned in our research, which originated from photoisomeric structure S-P instead of enol form S-N. The ESIPT mechanism was quantitatively explained by calculating the reactive Gibbs free energies. Finally, the frontier molecular orbitals and overlap between hole and electron analyses confirmed that the interaction between probe molecule and analytes impeded the excited-state intramolecular charge transfer (ESICT) behavior. Essential comprehending for ESICT and ESIPT properties were helpful in illuminating the probing mechanism, and to design an excellent fluorescence probe molecule.

Calculation of self-diffusion coefficient and surface tension of liquid alkali metals using square-well fluid

The self-diffusion coefficient (D) and the surface tension (γ) of the liquid alkali metals such as cesium (Cs) and rubidium (Rb) were calculated based on the Einstein's relation in a wide range of densities and temperatures. A developed mean spherical approximation (MSA) theory was applied to compute the direct correlation function using the effective square-well potential model for pair interaction in each temperature and density. The static structure factor, S(k), of the studied liquid species was evaluated by the proposed MSA theory in a wide range of wave vectors. The linear isothermal regularity equation of state was employed to determine the radial distribution function at a contact point at any thermodynamic state. A good agreement was obtained between the numerical results for both the D and γ values for the titled species and their available experimental data over the whole liquid range. For both liquids Cs and Rb, the temperature and density dependencies of the self-diffusion coefficient were investigated. Moreover, a correlation relation between the liquid surface tension and density and the temperature was found, in which the order of magnitude and sign of the coefficients were in good agreement with those obtained by experiment.

A new phenolic glycoside from the Idesia polycarpa Maxim. leaves

Phytochemical investigation on the ethyl acetate extract of Idesia polycarpa Maxim. Leaves led to the isolation of four phenolic glycoside isomers (1–4). Compound 2 appeared to be new reported phenolic glycoside, while compound 1 was the first time isolated from the titled species. Their structures were established by IR, UV, HRESI-MS and 1D and 2D NMR spectroscopies analysis and comparison of spectral data with previously reported data. The compounds 3 and 4 showed stronger activity of scavenging the DPPH free radical than the other two compounds, while the compounds 1 and 2 showed a significant activity of scavenging the ABTS free radical. Compounds 2 and 4 exhibited stronger cytotoxicity against HepG2 cell lines compared to compounds 1 and 3. Moreover, compound 3 presented the highest cytotoxicity against MCF cell lines with IC50 value of 37.17 ± 0.26 μg/mL than compounds 1, 2 and 4.

Phytochemical constituents from Galanthus alpinus Sosn. var. alpinus and their anticholinesterase activities

Phytochemical studies on Galanthus alpinus Sosn. var. alpinus from Turkey resulted in the isolation of 11 metabolites including, 1 terpenoid; (+)-blumenol A 1, 2 lignans; pinoresinol 2 and epipinoresinol 3, and 8 other compounds; (+)-homolycorine 4, (+)-8-O-demethylhomolycorine 5, arolycoricidine 6, N-Trans-feruloyltyramine 7, (−)-lycorine 8, nicotinic acid 9, O-methylnorbelladine 10 and hordenine 11. To the best of our knowledge, all compounds are reported for the first time from the title species. The chemical structures of the compounds were elucidated by MS, 1D and 2D experiments. Also, isolated compounds were subjected to in vitro acetylcholinesterase and butyrylcholinesterase inhibitory activity assays.

The nature of the chemical bond in borazine (B3N3H6), boroxine (B3O3H3), carborazine (B2N2C2H6), and related species

AbstractThe bonding problem in borazine (B3N3H6), boroxine (B3O3H3), and carborazine (B2N2C2H6) is successfully addressed through the consideration of the excited states of the constituent fragments, namely BH( ), NH( ), and CH( ). We propose the participation of resonant structures for all three species that help to explain the experimental findings. A discussion on the chemical pattern of the parental molecule benzene (C6H6) helps to make coherent the whole bonding analysis on the titled species.

Chemical Diversity in Ligularia oligonema

The chemical composition of a sample of the title species collected in Pianma, Lushui County, Yunnan Province of China, was examined. Two 3,6,10-oxygenated and two 3,6-oxygenated furanoeremophilanes were isolated. Structures of two new compounds were elucidated. The 3,6-oxygenated furanoeremophilanes were not detected in a sample of the same species previously collected in Laojunshan, Jianchuan County, Yunnan, indicating chemical diversity in the species.

Computational insights into novel dicobalt polynitrogen: structure, stability, intermolecular interaction, and application

Previous studies have suggested that polynitrogen species are significant as potential candidates for superior energetic material. In this paper, the polynitrogen species of Co2(N5)4 were reasonably designed and studied by the density functional theory (DFT), and five isomers of Co2(N5)4 were selected. These species were explored in detail, including structure, stability, intermolecular interaction, and application. The five isomers, each with its own special structure feature, were stable enough based on the analysis of bond energy, chemical hardness, and aromaticity. Furthermore, the intermolecular interactions suggested the presence of a covalent interaction in the Co–Co and N–N bonds, the electronic delocalization in cyclo-N5, and the ionic feature in the Co–N bond. In addition, all of the title species held high-energy content. Compared with the known high energy density materials of HB(N5)3Be2(N5)3BH, energetic material of nitromethane, and famous nitramine explosive HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane), Co2(N5)4 holds a stronger advantage. The five Co2(N5)4 species were located at 27.8–35.8 kcal/mol per N2 unit, their energy densities were about 2.73 × 104 MJ/kg, and their mass densities were in the range of 2.60–2.74 g/cm3. Significantly, the 4-1 was the most stable, and its density was also the greatest among the five species. Thus, it has the most potential as a high energy density material.