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51.
Didjour Albert Kambir Jean Brice Boti Ahmont Claude Landry Kablan Daouda Ballo Mathieu Paoli Virginie Brunini Flix Tomi 《Molecules (Basel, Switzerland)》2021,26(20)
The chemical variability and the in vitro anti-inflammatory activity of the leaf essential oil from Ivorian Isolona dewevrei were investigated for the first time. Forty-seven oil samples were analyzed using a combination of CC, GC(RI), GC-MS and 13C-NMR, thus leading to the identification of 113 constituents (90.8–98.9%). As the main components varied drastically from sample to sample, the 47 oil compositions were submitted to hierarchical cluster and principal components analyses. Three distinct groups, each divided into two subgroups, were evidenced. Subgroup I−A was dominated by (Z)-β-ocimene, β-eudesmol, germacrene D and (E)-β-ocimene, while (10βH)-1β,8β-oxido-cadina-4-ene, santalenone, trans-α-bergamotene and trans-β-bergamotene were the main compounds of Subgroup I−B. The prevalent constituents of Subgroup II−A were germacrene B, (E)-β-caryophyllene, (5αH,10βMe)-6,12-oxido-elema-1,3,6,11(12)-tetraene and γ-elemene. Subgroup II−B displayed germacrene B, germacrene D and (Z)-β-ocimene as the majority compounds. Germacrene D was the most abundant constituent of Group III, followed in Subgroup III−A by (E)-β-caryophyllene, (10βH)-1β,8β-oxido-cadina-4-ene, germacrene D-8-one, and then in Subgroup III−B by (Z)-β-ocimene and (E)-β-ocimene. The observed qualitative and quantitative chemical variability was probably due to combined factors, mostly phenology and season, then harvest site to a lesser extent. The lipoxygenase inhibition by a leaf oil sample was also evaluated. The oil IC50 (0.020 ± 0.005 mg/mL) was slightly higher than the non-competitive lipoxygenase inhibitor NDGA IC50 (0.013 ± 0.003 mg/mL), suggesting a significant in vitro anti-inflammatory potential. 相似文献
52.
Didjour Albert Kambir Ahmont Claude Landry Kablan Thierry Acafou Yapi Sophie Vincenti Jacques Maury Nicolas Baldovini Pierre Tomi Mathieu Paoli Jean Brice Boti Flix Tomi 《Molecules (Basel, Switzerland)》2022,27(12)
The variability of chemical composition of the leaf essential oil (EO) from Neuropeltis acuminata, a climbing liana growing wild in Ivory Coast, was investigated for the first time. The in vitro anti-inflammatory activity was also evaluated. Thirty oil samples were isolated from leaves collected in three forests of the country and analyzed using a combination of Column Chromatography (CC), Gas Chromatography with Retention Indices (GC(FID)), Gas Chromatography-Mass Spectrometry (GC-MS), and 13Carbon-Nuclear Magnetic Resonance (13C-NMR). Fractionation by CC led to the first-time isolation from natural source of δ-cadinen-11-ol, whose structural elucidation by one dimension (1D) and 2D-NMR spectroscopy is reported here. Finally, 103 constituents accounting for 95.7 to 99.6% of the samples’ compositions were identified. As significant variations of the major constituents were observed, the 30 oil compositions were submitted to hierarchical cluster and principal components analyses. Five distinct groups were evidenced: Group I, dominated by (E)-β-caryophyllene, kessane, and δ-cadinene, while the main constituents of Group II were germacrene B, ledol, α-humulene, (E)-γ-bisabolen-12-ol, and γ-elemene. Group III exhibited guaiol, germacrene D, atractylone, (E)-γ-bisabolen-12-ol, δ-cadinene and bulnesol as main compounds. Group IV was dominated by (E)-nerolidol, guaiol, selina-4(15),7(11)-diene and bulnesol, whereas (E)-β-caryophyllene, α-humulene and α-muurolene were the prevalent compounds of Group V. As the harvest took place in the same dry season in the three forests, the observed chemical variability could be related to harvest sites, which includes climatic and pedologic factors, although genetic factors could not be excluded. The leaf oil sample S24 behaved as a high inhibitor of LipOXygenase (LOX) activity (half maximum Inhibitory Concentration, IC50: 0.059 ± 0.001 mg mL−1), suggesting an anti-inflammatory potential. 相似文献
53.
The results of heats of mixing experiments on a series of ortho-substituted phenols with an amide or an ester are described. Substituents were chosen to span a wide range of electronic and steric character. Enthalpy of mixing results do not correlate solely with the acid strength of the phenol, or with a Hammett linear free-energy analysis. Rather, interactions are favored by the presence of groups with the ability to weaken the base strength of the proton donor while simultaneously increasing its acid strength. Such groups share a combination of electron-withdrawing ability and/or steric bulk that causes an effective decrease in the electron density about the phenolic oxygen. Trifluoromethyl and tert-butyl, and to a lesser extent halogen and hydroxy substituents ortho to the phenolic OH, give the highest exothermic enthalpies of mixing and are thus the most effective at promoting intermolecular interactions with weak bases such as amides and esters. These results should be useful in designing miscible or compatible polymer blends in which specific interactions such as hydrogen bonding are important. © 1995 John Wiley & Sons, Inc. 相似文献
54.
Applying a structure prediction computer programme (GRINSP=Geometrically Restrained INorganic Structure Prediction), the occurrence of 6-connected 3D networks was investigated, through AlF6 octahedra exclusive corner sharing. The five known AlF3 varieties were reproduced (α-, β-, η-, κ- and τ-AlF3) and seven hypothetical models were predicted. Among these still to be synthesized AlF3 phases, one can recognize two known structure types (TlCa2Ta5O15, Ba4CoTa10O30) and some easy to imagine intergrowths; however, a few others are completely unexpected, though simple. A comparison of the ab initio total energies of all the structures is provided, leading to the conclusion that the virtual models could well be viable. 相似文献
55.
The nickel nitrosyl compound [BseMe]Ni(PPh3)(NO) has been synthesized by the reaction of Ni(PPh3)2(NO)Br with potassium bis(2-seleno-1-methylimidazolyl)hydroborate, [BseMe]K. X-ray diffraction studies demonstrate that (i) the B–H group of the [BseMe] ligand interacts with the nickel center and (ii) the nitrosyl ligand is bent, with Ni–N–O bond angles of 149.1(3)° and 153.1(3)° for the two crystallographically independent molecules. The bent nature of the nitrosyl ligand in [BseMe]Ni(PPh3)(NO) is in marked contrast to the linearity observed for the tris(2-seleno-1-mesitylimidazolyl)hydroborato counterpart [TseMes]NiNO (180.0°). Density functional theory geometry optimization calculations demonstrate that the Ni?H–B interaction is not responsible for causing the nitrosyl ligand to bend, but rather the difference between [TseMes]NiNO and [BseMe]Ni(PPh3)(NO) is due to the [TseMes] ligand allowing the former molecule to adopt a structure with C3 symmetry. In contrast, the steric and electronic asymmetry of [Se2P] donor array of the [BseMe] and PPh3 ligand combination prevents [BseMe]Ni(PPh3)(NO) from having C3 symmetry and the nitrosyl ligand bends to stabilize the occupied M–N σ∗ antibonding orbital. 相似文献
56.
Aptamer-based colorimetric probe for cocaine 总被引:9,自引:0,他引:9
Complex of an anti-cocaine aptamer and the dye diethylthiotricarbocyanine behaves as a colorimetric sensor with attenuation in absorbance at 760 nm for cocaine in the concentration range of 2-600 muM. Mechanistic studies indicate an intermolecular displacement of the dye as the mechanism of action of the sensor. As the dye is insoluble in buffer, cocaine binding can be followed with the unaided eye as displaced dye precipitates and supernatant decolorizes. 相似文献
57.
ULTRAVIOLET IRRADIATION OF NUCLEIC ACIDS COMPLEXED WITH HEAVY ATOMS-II. PHOSPHORESCENCE AND PHOTODIMERIZATION OF DNA COMPLEXED WITH Ag* 总被引:6,自引:0,他引:6
Abstract— We have studied the luminescence (at 77°K) and photochemistry (at 298°K) of a variety of polynucleotides complexed with Ag+ . In all cases we observed that Ag+ induces a 'heavy atom effect' as indicated by quenching of fluorescence, enhancement of phosphorescence, and reduction of triplet lifetimes. The enhancement by Ag+ of the phosphorescence intensity of poly (dT) and DNA paralleled a 20-fold enhancement of the rate of thymine dimerization. These results suggest a possible triplet precursor for thymine dimerization in Ag+ complexes. Dimers were also made with a variety of triplet sensitizers, and Ag+ increased the dimer yield two- to four-fold, depending on the sensitizer used. 相似文献
58.
A new strategy in transition-state analog design is demonstrated to elicit catalytic antibodies. The strategy is based on substrate-assisted antibody catalysis and utilizes analogs designed to mimic the transition-state for intramolecular catalysis and thereby favor antibodies that can recruit catalytic groups from substrate. The hydrolysis of the benzoyl ester of cocaine provides an illustration. The benzoyl ester of cocaine is distant from the protonated nitrogen in the stable chair conformer but proximate in the strained boat form. An antibody stabilizing the boat form and approximating ester and amine could catalyze ester hydrolysis. To mimic the transition-state for the intramolecular catalysis, we synthesized a cocaine analog that replaces this ester with a methylenephenylphosphinate bridge to the tropane nitrogen. This bridged analog elicited 85 cocaine esterases out of 450 anti-analog antibodies-a performance markedly superior to that of a simple phosphonate ester-based analog with an identical tether. The correspondence of the analog to a "high energy" conformer eliminated product inhibition. For certain polyfunctional targets, substrate assistance can be an effective strategy for eliciting catalytic antibodies. 相似文献
59.
We isolate various sufficient conditions for a Banach space X to have the so-called Blum-Hanson property. In particular, we show that X has the Blum-Hanson property if either the modulus of asymptotic smoothness of X has an extremal behaviour at infinity, or if X is uniformly Gâteaux smooth and embeds isometrically into a Banach space with a 1-unconditional finite-dimensional decomposition. 相似文献
60.
1H NMR chemical shifts were examined for mixtures of sodium 8-phenyloctanoate (Na-ω-PhOct) in deuterated aqueous solutions of varying compositions of ethoxylated alcohols. In addition, diffusion-oriented spectroscopy experiments (DOSY) were performed on selected compositions to obtain the diffusion coefficients of the ethoxylated alcohols in the mixed micelles. As expected, the alcohol/surfactant systems exhibit behavior typical to that of an anionic surfactant/alcohol system, in that the critical micellar concentrations and aggregation numbers decrease with increasing alcohol concentration in the mixed solvent. The 1H NMR aromatic solute induced shifts (ASIS effects) on the alcohol and surfactant protons give significant information on the locations of the alcohol groups in the mixed micelle. All these results are interpreted in terms of the structure of the alcohol/surfactant systems as a function of their composition. 相似文献