Chemistry Central Journal最新文献

Background: Benzoxazole is the most important class of heterocyclic compound in medicinal chemistry. It has been incorporated in many medicinal compounds making it a versatile heterocyclic compound that possess a wide spectrum of biological activities.

Results: The molecular structures of synthesized benzoxazole derivatives were confirmed by physicochemical and spectral means. The synthesized compounds were further evaluated for their in vitro biological potentials i.e. antimicrobial activity against selected microbial species using tube dilution method and antiproliferative activity against human colorectal carcinoma (HCT 116) cancer cell line by Sulforhodamine B assay.

Conclusion: In vitro antimicrobial results demonstrated that compounds 4, 5, 7 and 16 showed promising antimicrobial potential. The in vitro anticancer activity indicated that compounds 4 and 16 showed promising anticancer activity against human colorectal cancer cell line (HCT 116) when compared to standard drug and these compounds may serve as lead compound for further development of novel antimicrobial and anticancer agents.

Background: Spiropyrrolidine tethered piperidone heterocyclic hybrids were synthesized with complete regio- and stereoselectively in excellent yield via a tandem three-component 1,3-dipolar cycloaddition and subsequent enamine reaction in [bmim]Br. The synthesized compounds were evaluated for their anticancer activity against FaDu hypopharyngeal tumor cells.

Findings: Interestingly, most compounds displayed cytotoxicities similar to the standard anticancer agent bleomycin, with two of them (5a and 5g) being slightly more active than the reference drug.

Conclusion: Synthesized compounds have also been evaluated for their apoptosis-inducing properties in a cancer cell model, finding that treatment with compounds 5a-e led to apoptotic cell death.

The current study investigated hepatoprotective and antioxidant effects of Aegle marmelos leaves extract. The major constituent present in the extract i.e. rutin was quantified by using HPLC. Further, the study explored hepatoprotective effect of A. marmelos (70% ethanol extract) in combination with piperine. The normal control and carbon tetrachloride (CCl₄) administered rats were divided into 7 groups. Hepatic damage biomarkers were determined in serum samples and oxidative stress biomarkers (malondialdehyde, reduced glutathione, glutathione reductase, glutathione peroxidase, glutathione-S-transferase, superoxide dismutase and catalase), pro-inflammatory and anti-inflammatory cytokines were determined in liver homogenates. CCl₄ caused marked liver damage as evident by significant increased activities of serum alkaline phosphatase, bilirubin, lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, Interleukin 10 and Tumor necrosis factor-α levels compared to normal control. The oxidative stress parameters also significantly modulated in CCl₄ group as compared to normal control. Treatment with A. marmelos reduced the severity of toxicity in a dose dependent fashion and the results of A. marmelos extract 50 mg/kg group were comparable to silymarin group. The low dose of A. marmelos extract (25 mg/kg) per se did not significantly reversed the hepatotoxicity but low dose of A. marmelos in combination with piperine showed significant reversal of hepatotoxicity. In conclusion, A. marmelos exerts potential hepatoprotective activity through its antioxidant and anti-inflammatory properties which was enhanced by co-treatment with piperine.

Palladium nanoparticles display fascinating electronic, optical and catalytic properties, thus they can be used for various applications such as sensor fabrication. Conducting polymers such as polyaniline have also been widely used in sensor technology due to its cost effectiveness, versatility, and ease of synthesis. In this research, attention was given to unify the exceptional properties of these two materials and construct palladium nanoparticle coated polyaniline films to detect hydrogen and moisture. Electrochemical polymerization of aniline was carried out on gold sputtered epoxy resin boards. Polyaniline film was generated across a gap of 0.2 mm created by a scratch made on the gold coating prior to electrochemical polymerization. A palladium nanoparticle dispersion was prepared using sonochemical reduction method and coated on to polyaniline film using drop-drying technique. Polyaniline only films were also fabricated for comparative analysis. Sensitivity of films towards humidity and hydrogen was evaluated using impedance spectroscopy in the presence of the respective species. According to the results, polyaniline films exhibited an impedance drop in the presence of humidity and the response was significantly improved once palladium nanoparticles were incorporated. Interestingly, polyaniline only films did not respond to hydrogen. Nevertheless, palladium nanoparticle coated polyaniline films exhibited remarkable response towards hydrogen.

Background: A new series of benzoxazole analogues was synthesized and checked for their in vitro antibacterial, antifungal and anticancer activities.

Results and discussion: The synthesized benzoxazole compounds were confirmed by IR, ¹H/¹³C-NMR, mass and screened for their in vitro antimicrobial activity against Gram-positive bacterium: Bacillus subtilis, four Gram-negative bacteria: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi and two fungal strains: Candida albicans and Aspergillus niger using tube dilution technique and minimum inhibitory concentration (MIC) was noted in µM and compared to ofloxacin and fluconazole. Human colorectal carcinoma (HCT116) cancer cell line was used for the determination of in vitro anticancer activity (IC₅₀ value) by Sulforhodamine B assay using 5-fluorouracil as standard drug.

Conclusion: The performed study indicated that the compounds 1, 10, 13, 16, 19, 20 and 24 had highest antimicrobial activity with MIC values comparable to ofloxacin and fluconazole and compounds 4, 6, 25 and 26 had best anticancer activity in comparison to 5-fluorouracil.

Background: Single cell oil has long been considered an alternative to conventional oil sources. The oil produced can also be used as a feedstock for biodiesel production. Oleaginous yeasts have relatively high growth and lipid production rates, can utilize a wide variety of cheap agro-industrial wastes such as molasses, and can accumulate lipids above 20% of their biomass when they are grown in a bioreactor under conditions of controlled excess carbon and nitrogen limitation.

Results: In this study, Rhodotorula kratochvilovae (syn, Rhodosporidium kratochvilovae) SY89 was cultivated in a nitrogen-limited medium containing cane molasses as a carbon source. The study aims to provide not only information on the production of single cell oil using R. kratochvilovae SY89 on cane molasses as a biodiesel feedstock, but also to characterize the biodiesel obtained from the resultant lipids. After determination of the sugar content in cane molasses, R. kratochvilovae SY89 was grown on the optimized cane molasses for 168 h. Under the optimized conditions, the yeast accumulated lipids up to 38.25 ± 1.10% on a cellular dry biomass basis. This amount corresponds to a lipid yield of 4.82 ± 0.27 g/L. The fatty acid profiles of the extracted yeast lipids were analyzed using gas chromatography, coupled with flame ionization detector. A significant amount of oleic acid (58.51 ± 0.76%), palmitic acid (15.70 ± 1.27%), linoleic acid (13.29 ± 1.18%) and low amount of other fatty acids were detected in the extracted yeast lipids. The lipids were used to prepare biodiesel and the yield was 85.30%. The properties of this biodiesel were determined and found to be comparable to the specifications established by ASTM D6751 and EN14214 related to biodiesel quality.

Conclusions: Based on the results obtained, the biodiesel from R. kratochvilovae SY89 oil could be a competitive alternative to conventional diesel fuel.

Environmental scientists are currently assessing the ability of hyper-spectral remote sensing to detect, identify, and analyze natural components, including minerals, rocks, vegetation and soil. This paper discusses the use of a nonlinear reflectance model to distinguish multicomponent particulate mixtures. Analysis of the data presented in this paper shows that, although the identity of the components can often be found from diagnostic wavelengths of absorption bands, the quantitative abundance determination requires knowledge of the complex refractive indices and average particle scattering albedo, phase function and size. The present study developed a method for spectrally unmixing halite and gypsum combinations. Using the known refractive indexes of the components, and with the assistance of Hapke theory and Legendre polynomials, the authors develop a method to find the component particle sizes and mixing coefficients for blends of halite and gypsum. Material factors in the method include phase function parameters, bidirectional reflectance, imaginary index, grain sizes, and iterative polynomial fitting. The obtained Hapke parameters from the best-fit approach were comparable to those reported in the literature. After the optical constants (n, the so-called real index of refraction and k, the coefficient of the imaginary index of refraction) are derived, and the geometric parameters are determined, single-scattering albedo (or ω) can be calculated and spectral unmixing becomes possible.

Background: The atmosphere has become a major transport corridor for free radicals and particulate matter from combustion events. The motivation behind this study was to determine the nature of particulate emissions and surface bound radicals formed during the thermal degradation of diesel blends in order to assess the health and environmental hazards of binary transport fuels.

Methodology: Accordingly, this contribution explored the interactions that occur when Croton megalocarpus biodiesel and fossil diesel in the ratio of 1:1 by weight were co-pyrolyzed in a quartz reactor at a residence time of 0.5 s under an inert flow of nitrogen at 600 °C. The surface morphology of the thermal char formed were imaged using a Feld emission gun scanning electron microscope (FEG SEM) while Electron paramagnetic resonance spectrometer (EPR) was used to explore the presence of free radicals on the surface of thermal char. Molecular functional groups adsorbed on the surface of thermal char were explored using Fourier transform infrared spectroscopy (FTIR).

Results: FTIR spectrum showed that the major functional groups on the surface of the char were basically aromatic and some methylene groups. The particulate emissions detected in this work were ultrafine (~ 32 nm). The particulates are consistent with the SEM images observed in this study. Electron paramagnetic resonance results gave a g-value of 2.0027 characteristic of carbon-based radicals of aromatic nature. Spectral peak-to-peak width (∆Hp-p) obtained was narrow (4.42 G).

Conclusions: The free radicals identified as carbon-based are medically notorious and may be transported by various sizes of particulate matter on to the surface of the human lung which may trigger cancer and pulmonary diseases. The nanoparticulates determined in this work can precipitate severe biological health problems among humans and other natural ecosystems.

The advanced biochemical characterisation of green, red lentil and wheat flours was performed by assessing their folic acid content as well as individual minerals, amino acids, fatty acids and volatile compounds. Moreover, a nutritionally improved wheat-lentil composite flour, with a content of 133.33 μg of folic acid/100 g, was proposed in order to assure the folic acid daily intake (200 μg) for an adult person. The wheat and lentil flours percentages used for the composite were calculated by using the equations for total material balance and folic acid content material balance. Bread was selected as model food for the composite flour due to its high daily intake (~ 250 g day^-1) and to its great potential in biofortification. By this algorithm, two composite flours were developed, wheat-green lentil flour (22.21-77.79%) and wheat-red lentil flour (42.62-57.38%), their advanced biochemical characteristics being predicted based on the determined compositions of their constituents. The baking behaviour of the new developed wheat-lentils composite flours with optimised folic acid content was tested. In order to objectively compare the bread samples, texture profile analysis was considered the most relevant test. A good baking behaviour was observed for the wheat-red lentil bread, while for the wheat-green lentil composite flour, encouraging results were obtained.

The particularities of cesium incorporation into synthetic calcium phosphates with either apatite or whitlockite-type structures were investigated using the sorption process from aqueous solution and further heating to 700 °C. The nanoparticles for sorption were prepared by wet precipitation from aqueous solutions at a fixed molar ratio of Ca/P = 1.67 and two different ratios of CO₃^2-/PO₄^3- (0 or 1). The obtained substituted calcium phosphates and corresponding samples after the sorption of cesium from solutions with different molar concentrations (c(Cs⁺) = 0.05, 0.1 and 0.25 mol L^-1) were characterized by powder X-ray diffraction, FTIR spectroscopy, scanning electron microscopy and elemental analysis. Based on the combination of X-ray diffraction and elemental analyses data for the powders after sorption, the cesium incorporated in the apatite- or whitlockite-type structures and its amount increased with its concentration in the initial solution. For sodium-containing calcium phosphate even minor content of Cs⁺ in its composition significantly changed the general principle of its transformation under annealing at 700 °C with the formation of a mixture of α-Ca₃(PO₄)₂ and cesium-containing apatite-related phase. The obtained results indicate the perspective of using of complex substituted calcium phosphates nanoparticles for immobilization of cesium in the stable whitlockite- or apatite-type crystal materials.