Journal of the Mexican Chemical Society

Synthesis of novel pyridine-connected piperidine and 2H-thiopyran derivatives and their larvicidal, nematicidal, and antimicrobial activities

2019-04-23T19:06:46+00:00

A series of novelpyridine-connected piperidine derivatives (2a-g) and pyridine-connected 2H-thiopyran derivatives (4a-g) were synthesized and screened for larvicidal, nematicidal, and antimicrobial activities. Compound 4e exhibited larvicidal activity against second instar larvae with an LD₅₀ value of 0.8μg/mL. In addition, 4e exhibited high nematicidal activity, with an LD₅₀ value of 3.2μg/mL.Compounds 2e (MIC: 4 μg/mL) and 2d (MIC: 4 μg/mL) exhibited high antibacterial activity against Klebsiella pneumoniae and Escherichia coli, respectively. Compounds 4b (MIC: 0.25 μg/mL) and 4f (MIC: 2 μg/mL) showed high antifungal activity against Candida albicans and Microsporum audouinii, respectively. Therefore, it can be suggested that compounds 2e, 2d, 4e, 4b, and 4f may be useful as lead molecules for the development of new classes ofdrugs with larvicidal,nematicidal,and antimicrobial activities.

A facile synthesis of glycerol carbonate by transesterification of glycerol with dimethyl carbonate: Ceria based catalysts

2019-04-23T19:06:48+00:00

Abstract. Solid base catalysts such as Ceria-Zirconia-Magnesia with different mole ratio of magnesium were prepared by impregnation method and characterized by CO₂-TPD, PXRD, FT-IR and ICP-OES analysis. The catalytic activity of the catalysts was tested in the liquid phase transesterification of glycerol with dimethyl carbonate to synthesise glycerol carbonate. Optimization of reaction condition was carried out by varying the molar ratio of the reactants, temperature and time. The highest yield (97 %) of glycerol carbonate was obtained at a reactant molar ratio of 1:3 at 120 °C in 6 h. Study of reusability and reactivation of solid base catalyst was also taken up. A suitable base catalysed mechanism for the formation of glycerol carbonate is proposed.

Resumen. Se prepararon catalizadores de base sólida como Ceria-Zirconia-Magnesia con diferentes proporciones molares de magnesio mediante el método de impregnación y se caracterizaron por análisis de CO₂-TPD, PXRD, FT-IR e ICP-OES. La actividad catalítica de los catalizadores se probó en la transesterificación en fase líquida de glicerol con carbonato de dimetilo para sintetizar carbonato de glicerol. La optimización de las condiciones de reacción se llevó a cabo variando la relación molar de los reactivos, la temperatura y el tiempo. El mayor rendimiento (97 %) de carbonato de glicerol se obtuvo a una relación molar reactiva de 1:3 a 120 °C en 6 h. También se realizó un estudio de la reutilización y reactivación del catalizador de base sólida. Se propone un mecanismo catalítico básico adecuado para la formación de carbonato de glicerol.

Refractometric study on binary, ternary, and quaternary solutions made by water, methanol, ethanol, glycerol, D-glucose monohydrate (DGMH), sucrose, and sodium chloride at T = 293.15 K and atmospheric pressure

2019-04-23T19:06:48+00:00

The glycerol, D-glucose monohydrate (DGMH), sucrose, and sodium chloride are used in food industries and the measurement of properties for these components and their aqueous solutions can be important. In this research work, the refractive indices for binary solutions of (methanol + glycerol), (ethanol + glycerol), ternary solutions of (water + glycerol + DGMH), (water + glycerol + sucrose), (water + sucrose + DGMH), (water + sucrose + ethanol), (water + ethanol + DGMH), (water + NaCl + DGMH), (water + methanol + NaCl), (water + ethanol + NaCl), (water + NaCl + glycerol), (water + sucrose + NaCl), and quaternary solutions of (water + ethanol + sucrose + DGMH), (water + ethanol + sucrose + glycerol), (water + NaCl + sucrose + glycerol) were measured in wide range of mole fractions at T = 293.15 K and atmospheric pressure. For binary solutions of this study, the changes of refractive index on mixing, ∆n_D, were calculated in each mole fraction at T = 293.15 K. Also, the refractive index of binary solutions was fitted by a semi-empirical equation. The constant of this equation, K_r, was represented by Koohyar et al. in 2011. This constant can be used to investigate power of interactions between solute and solvent molecules. For ternary and quaternary solutions of this study, a semi-empirical equation was used to determine refractive indices at given temperature. The comparison between calculated and experimental refractive indices shows that there is a good agreement between them especially in lower molal concentrations.

GC/MS analysis and bioactive properties of extracts obtained from Clusia minor L. leaves

2019-04-23T19:06:47+00:00

Clusia minor L. is traditionally used to treat many disorders that including pain and inflammation such as sores and warts. Four extracts from the leaves of plant were prepared: hexane (CMH-A), ethyl acetate (CMH-B), methanol (CMH-C) and ethanol (CMH-E) and the pharmacological (antioxidant and anti-inflammatory properties) and toxicity effects were examined. Previously, the main constituents from CMH-A extract was revealed. Here, we present the GC/MS analysis of CMH-B and CMH-C. Thirty three compounds were identified in the CMH-B extract and twenty seven compounds in the CMH-C. The presence of D-α-tocopherol and lupeol was relevant in both extracts. The only sterols identified were sitosterol and stigmasterol. All of them showed effective radical scavenger properties in the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay, being CMH-E extract the most promissory (IC₅₀= 10.25 µg/mL). CMH-A, C and E extracts, administered topically (0.5–4 mg per ear), significant reduced ear edema induced by croton oil at 4 mg per ear, meanwhile CMH-B that was be able to significant reduce the inflammation at the dose of 2 mg per ear. We evaluated also the cytotoxic activity of the extracts against kidney cells (BHK), colon cancer (CT26), endothelial cancer cells (EA.hy926) and breast cancer (4T1). CMH-B extract showed the most cytotoxicity effect, with IC₅₀ values in the range of 32.01-203.5 µg/mL. In addition, no oral acute toxicity after mice exposure to Clusia minor L. extracts was observed. The results suggest Clusia minor L. may be a good potential source of new bioactive agents for developing medicinal agents.

Full validation of curcumin analytical method by LC-MS/MS points out that the degree of hemolysis in plasma affects the quantitation: application in dog plasma study

2019-04-23T19:06:47+00:00

Abstract. Curcumin has gained great attention in the last decades due to its fascinating properties for humans, such as anti-inflammatory or as cytotoxic against cancer. These effects are also claimed for pets such as cats and dogs, where curcumin administration is a daily practice routine. However, curcumin presents poor oral bioavailability, driving scientists to look for new delivery systems. In the last decades, several analytical methods for the quantification of curcumin in plasma have been published. To our knowledge there are no published reports on the effect of the level of hemolysis in the determination of this compound. In the present paper, a highly specific, sensitive and selective method is presented using Molecular Reaction Monitoring (SRM) using positive ionization (ESI+) mode. Curcumin and clopidogrel bisulfate – used as internal standard (IS) – were separated on an Acquity UPLC BECH Shield RP 18 column (1.7µm, 2.1 X 100mm) with 0.1% formic acid in acetonitrile and water in proportion of 60:40 (v/v). The analyte transitions were 369.3→177.06 m/z for curcumin and 322→212.05 m/z for IS. The method was fully validated and showed good linearity (R² ≥ 0.999) over the range of 3-160 ng/mL. The Relative Standard Deviation (RSD) were less than 6% for intra-and inter-day analysis and recovery spanned 85-95%. We proved that the degree of hemolysis impaired curcumin quantitation. This method was applied to test curcumin bioavailability in both a mucoadhesive nanocapsule formulation and traditional capsules in dogs that attended routine veterinary consultation.

Resumen. La curcumina ha ganado gran atención en las últimas décadas debido a sus propiedades terapéuticas para los humanos, como antiinflamatorio o citotóxico contra el cáncer. Estos efectos también se observan en pequeñas especies como gatos y perros, donde la administración de curcumina se ha vuelto una alternativa. Sin embargo, la curcumina presenta una baja biodisponibilidad oral, lo que impulsa a los científicos a buscar nuevos sistemas de administración. En las últimas décadas, se han publicado varios métodos analíticos para la cuantificación de curcumina en plasma. Actualmente, no hay informes publicados sobre el efecto del grado de hemólisis en la determinación de este compuesto. En este trabajo se desarrolló un método específico, sensible y selectivo utilizando el Monitoreo de reacción seleccionado (SRM) en modo de ionización positiva (ESI +). La curcumina y el bisulfato de clopidogrel, utilizado como patrón interno (IS), se separaron en una columna Acquity UPLC BECH Shield RP 18 (1,7 μm, 2,1 X 100 mm) con ácido fórmico al 0,1% en acetonitrilo y agua a una proporción de 60:40 (v/v). Las transiciones de los analitos fueron 369.3 → 177.06 m/z para curcumina y 322 → 212.05 m/z para IS. El método fue validado y demostró ser lineal (r² ≥ 0.999) en el rango de 3-160 ng/mL. La desviación relativa estándar (RSD) fue inferior al 6% para el análisis intra e interdía y el porcentaje de recuperación fue 85-95%. Se descubrió que el grado de hemólisis afecta la cuantificación de curcumina. El método desarrollado se aplicó para evaluar la biodisponibilidad de curcumina tanto en una formulación de nanocápsulas mucoadhesivas como en cápsulas tradicionales en perros que asistieron a consultas veterinarias de rutina.

Recyclable Nanomagnetic Fe3O4@APTES catalyst role on the Hydrolysis of Polycarbonate Wastes

2019-04-23T19:06:47+00:00

In this research, the effect of (3-Aminopropyl) triethoxysilane (APTES) modified Fe₃O₄ (Fe₃O₄@APTES) core-shell nanomaterials as the recyclable heterocatalyst on the recovery of bisphenol-A (BPA) from hydrolysis of polycarbonate (PC) wastes were investigated. In the evaluated reactions, water and diethylene glycol (DEG) were used as the green solvent composition and the water as well as magnetic heterocatalyst content were optimized. By examining the results of the above-mentioned reactions, it was observed that by using 25 pbw of water and 2 pbw of magnetic heterocatalyst (both based on total waste and solvent weights), BPA achieved in 100% yield. The Fe₃O₄@APTES nanomaterials as the heterocatalyst can be recovered and reused up to five intervals with our significant activity losses. The resulting BPA and nanomaterials has been characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and spectroscopic methods (¹H NMR, ¹³C NMR, FT-IR).

Antiproliferative and anti-inflammatory acyl glucosyl flavones from the leaves of Bursera copallifera

2019-04-23T19:06:47+00:00

Bursera copallifera(DC) Bullock (Burseraceae) is a plant species used in folk medicine for the treatment of inflammation (bronchitis, cough). The dichloromethane-methanol extract (DML) of B. copallifera leaves was found to possess important antiproliferative and anti-inflammatory activities. In order to further correlate these activities with the phytochemical components, the bioactivity-guided fractionation of the DML extract allowed the isolation of an active fraction which was constituted of five compounds characterized as as luteolin-3'-O-(3''-O-E-p-coumaroyl)-α-L-rhamnopyranoside (1), luteolin-3'-O-(2''-O-E-p-coumaroyl)-α-L-rhamnopyranoside (2), a-amyrin (3), 3-epilupeol (4) and stigmasterol (5). Among the five isolated constituents, the triterpenes 3 and 4, and the sterol 5 have been already well known by their anti-inflammatory properties. Flavone 2 (Luteolin-3'-O-(2''-O-E-p-coumaroyl)-α-L-rhamnopyranoside)was responsible for the antiproliferative activity, showing in vitro cytotoxic activity against MCF-7 human cancer cell line with IC₅₀ value of 13.9 µM. By the other hand flavone (1) exhibited COX-1 inhibition (IC₅₀ = 93 mM). Flavone 1, together with the triterpenes 3 and 4 were the responsible for inhibiting TPA-induced inflammation by inhibit COX-1 enzyme. Therefore, these results support the traditional use of the infusion made with the leaves of B. copallifera as an anti-inflammatory agent.

Synthesis, characterization and cytotoxic activity of tioconazole coordination compounds with nickel(II), palladium(II) and platinum(II)

2019-04-23T19:06:47+00:00

Coordination compounds of nickel(II), palladium(II) and platinum(II) with tioconazole (tcnz) were synthesized and characterized by infrared, UV-Vis-NIR, elemental analysis, molar conductivity, magnetic susceptibility, mass spectrometry, NMR spectroscopy and X- ray diffraction. Tioconazole presented a monodentate coordination mode, through the nitrogen atom of the imidazolic ring. The Ni^II compounds stabilized an octahedral geometry. In [Ni(tcnz)₂(NO₃)₂]^.H₂O the coordinated nitrate presented a bidentate coordination mode, while for the [Ni(tcnz)₂(OAc)₂]^.3H₂O compound, the acetate behaves as a bridging ligand. When different molar ratios were used on the reaction synthesis, three or six ligands were coordinate to the nickel(II) atom, [Ni(tcnz)₃Br₂(H₂O)], [Ni(tcnz)₆]Cl₂ and [Ni(tcnz)₆]Br₂. The palladium(II) and platinum(II) compounds, [Pd(tcnz)₂Cl₂], [Pt(tcnz)₂Cl₂]^.2H₂O and [Pd(tcnz)₂(OAc)₂], stabilized a trans-square planar geometry. The compounds [Ni(tcnz)₆]X₂ give place to 3D supramolecular arrangements through hydrogen bonding (X∙∙∙H, X = Cl and Br) and p∙∙∙p stacking interactions, between the six membered rings of neighbouring molecules. The in vitro cytotoxic activity of the synthesized compounds was studied in four different human carcinoma cell lines: HCT-15 (colon), HeLa (cervix-uterine), MCF-7 (breast) and PC-3 (prostate).