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101.
Afoulous S Ferhout H Raoelison EG Valentin A Moukarzel B Couderc F Bouajila J 《Molecules (Basel, Switzerland)》2011,16(10):8273-8291
Helichrysum gymnocephalum essential oil (EO) was prepared by hydrodistillation of its leaves and characterized by GC-MS and quantified by GC-FID. Twenty three compounds were identified. 1,8-Cineole (47.4%), bicyclosesquiphellandrene (5.6%), γ-curcumene (5.6%), α-amorphene (5.1%) and bicyclogermacrene (5%) were the main components. Our results confirmed the important chemical variability of H. gymnocephalum. The essential oil was tested in vitro for cytotoxic (on human breast cancer cells MCF-7), antimalarial (Plasmodium falciparum: FcB1-Columbia strain, chloroquine-resistant) and antioxidant (ABTS and DPPH assays) activities. H. gymnocephalum EO was found to be active against MCF-7 cells, with an IC(50) of 16 ± 2 mg/L. The essential oil was active against P. falciparum (IC(50) = 25 ± 1 mg/L). However, the essential oil exhibited a poor antioxidant activity in the DPPH (IC(50) value > 1,000 mg/L) and ABTS (IC(50) value = 1,487.67 ± 47.70 mg/L) assays. We have reviewed the existing results on the anticancer activity of essential oils on MCF-7 cell line and on their antiplasmodial activity against the P. falciparum. The aim was to establish correlations between the identified compounds and their biological activities (antiplasmodial and anticancer). β-Selinene (R2 = 0.76), α-terpinolene (R2 = 0.88) and aromadendrene (R2 = 0.90) presented a higher relationship with the anti-cancer activity. However, only calamenene (R2 = 0.70) showed a significant correlation for the antiplasmodial activity. 相似文献
102.
Alexis Rojas-Gonzlez Claudia Yuritzi Figueroa-Hernndez Oscar Gonzlez-Rios Mirna Leonor Surez-Quiroz Rosa María Gonzlez-Amaro Zorba Josu Hernndez-Estrada Patricia Rayas-Duarte 《Molecules (Basel, Switzerland)》2022,27(11)
The demand of foods with high antioxidant capacity have increased and research on these foods continues to grow. This review is focused on chlorogenic acids (CGAs) from green coffee, which is the most abundant source. The main CGA in coffee is 5-O-caffeoylquinic acid (5-CQA). Coffee extracts are currently the most widely used source to enhance the antioxidant activity of foods. Due to the solubility of CGAs, their extraction is mainly performed with organic solvents. CGAs have been associated with health benefits, such as antioxidant, antiviral, antibacterial, anticancer, and anti-inflammatory activity, and others that reduce the risk of cardiovascular diseases, type 2 diabetes, and Alzheimer’s disease. However, the biological activities depend on the stability of CGAs, which are sensitive to pH, temperature, and light. The anti-inflammatory activity of 5-CQA is attributed to reducing the proinflammatory activity of cytokines. 5-CQA can negatively affect colon microbiota. An increase in anthocyanins and antioxidant activity was observed when CGAs extracts were added to different food matrices such as dairy products, coffee drinks, chocolate, and bakery products. The fortification of foods with coffee CGAs has the potential to improve the functionality of foods. 相似文献
103.
Andrea Rodriguez Loriett Cartaya Alexis Maldonado Edgar Marquez José R. Mora Tania Cordova 《Molecular physics》2017,115(14):1624-1632
The study on the mechanism of the gas-phase elimination or thermal decomposition kinetics of 2, 2-dimethyl-3-butenal has been carried out by using theoretical calculation at MP2, combined ab initio CBSQB3 and DFT (B3LYP, B3PW91, MPW1PW91, PBEPBE, PBE1PBE, CAMB3LYP, M06, B97d) levels of theory. A good reasonable agreement between experimental and calculated parameters was obtained by using CAMB3LYP/6-311G(d,pd) calculations. The contrasted calculated parameters against experimental values suggested decarbonylation reaction to proceed through a concerted five-membered cyclic transition state type of mechanism, involving the hydrogen transfer from the carbonyl carbon to the gamma carbon, consistent with observed kinetic isotope effect. The breaking of alpha carbon–carbonyl carbon bond to produce carbon monoxide is 50% advanced in the transition state. The reaction mechanism may be described as a concerted moderately non-synchronous process. Examination of the Atoms in Molecules (AIM) analysis of electron density supports the suggested mechanism. 相似文献
104.
Alexis Marin 《Mathematische Annalen》1987,278(1-4):211-217
Sans résuméDédié à Friedrich Hirzebruch 相似文献
105.
E. Alexis 《Analytical and bioanalytical chemistry》1935,103(11-12):452-452
106.
We present a nondestructive and noncontact extensometry technique, which has been developed in order to study the behavior of different materials such as polycarbonate, araldite, urethane, etc. A spectral analysis of a crossed grating marked on the surface of a specimen and recorded by a charge coupled device camera is presented. The procedure is based on the use of a bidimensional fast Fourier transform algorithm coupled with an interpolation process. It leads to the accurate determination of frequencies. Numerical simulations have been made to evaluate the strain sensitivity; it depends on both the initial phase and the number of cycles characterizing the grid. Theoretically, the strain sensitivity can reach 10-5 in best cases, but practically it is notbetter than 10-4. Several applications on different materials are presented: polyurethane, paper and cloth. 相似文献
107.
Peter Barker Alexis Bishop Halina Rubinsztein-Dunlop 《Applied physics. B, Lasers and optics》1997,64(3):369-376
A novel flow-tagging technique is presented which was employed to measure gas velocities in the free stream of a shock tube.
This method is based on the laser spectroscopic techniques of Laser-Enhanced Ionisation (LEI) and Laser-Induced Fluorescence
(LIF). The flow in the shock tube is seeded with small amounts of sodium, and LEI is used to produce a substantial depletion
of neutral sodium atom concentration in a well-defined region of the flow, by using two wavelength-resonance excitation and
subsequent collisional ionisation. At a specific time delay, single-laser-pulse planar LIF is utilised to produce a two-dimensional
(2-D) inverse image of the depleted tagged region downstream of the flow. By measuring the displacement of the tagged region,
free stream velocities in a shock tube were determined. Large variations in the concentration of sodium seeded into the flow
were observed and even in the presence of these large variations accurate free-stream velocity measurements were obtained.
The experimentally determined value for velocity compares very well with the predicted velocity.
Received: 25 March 1996/Revised version: 8 July 1996 相似文献
108.
109.
Carmen R. Maldonado Miguel Quirs Juan M. Salas 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(8):o489-o491
The title compound, C5H5N5OS·H2O, crystallizes as the monohydrate. Disorder of the H atoms that participate in the hydrogen bonds implies that two different tautomers are present in the crystal structure, one of them with both acidic H atoms attached to the imidazole ring and the other with one acidic H atom on each ring. 相似文献
110.
Leleu S Penhoat M Bouet A Dupas G Papamicaël C Marsais F Levacher V 《Journal of the American Chemical Society》2005,127(45):15668-15669
A new and unprecedented exploitation of quinolinium thioester salts 2 in peptide bond formation is reported. These synthetic tools were assessed during the preparation of a number of dipeptides 3a-f obtained in good yields with complete stereochemical integrity. A sequential mechanism related to a prior amine capture strategy is well-established. Additionally, a tripeptide 3g was prepared according to a "safety-catch" approach, thus demonstrating the important potential of these new synthetic tools in the design of new safety-catch linkers exploitable in Solid-Phase Peptide Synthesis (SPPS). 相似文献