Anti-lipid peroxidation and induction of apoptosis in the erythroleukaemic cell line K562 by extracts from (Tunisian) Rhamnus alaternus L. (Rhamnaceae)

Total oligomer flavonoids (TOF) enriched and ethyl acetate (EA) extracts from Rhamnus alaternus induce apoptotic death in human chronic myelogenous leukaemia K562 cell line, as demonstrated by gel electrophoresis, which demonstrates the characteristic ladder patterns of DNA fragmentation and the proteolytic cleavage of poly(ADP ribose) polymerase (PARP). The effect of R. alaternus extract in reducing oxidative stress was evaluated by anti-lipid peroxidation which was monitored by measuring malondialdehyde level in K562 cultured cells. The TOF and EA extracts were found to be effective to protect against lipid peroxidation. Their IC?? values were 196 and 273?μg?mL?1, respectively. These findings suggest that R. alaternus extracts exhibit potential antioxidant and proapoptotic properties.     

A templated electrosynthesis of macroporous NiAl layered double hydroxides thin films

Colloidal crystals of polystyrene (PS) beads self-assembled on Pt electrode were used as a sacrificial template to electrosynthesis thin films of macroporous Layered Double Hydroxides (LDH). Such nanostructured materials display a high internal surface area and porosity leading to enhanced electrochemical performance.     

ab-initio investigations of electronic and magnetic properties of the tetragonal chalcopyrite BeTiTe2 compound: DFT + U study

The spin-polarised structural, electronic, and magnetic properties of the chalcopyrite BeTiTe₂ compound in tetragonal structure (Be_0.50Ti_0.50Te) have been studied by employing first-principles full-potential linearised augmented plane wave plus local orbitals (FP-L/APW?+?lo) method within the density functional theory (DFT) and implemented in WIEN2k code. The exchange and correlation energy are described in two frameworks of GGA (generalised gradient approximation) and GGA?+?U (U is the Hubbard term). The structural analysis confirms that the ferromagnetic phase of the tetragonal BeTiTe₂ compound (Be_0.50Ti_0.50Te) is energetically more favourable; also different equilibrium lattice parameters, such as lattice constants (a₀ and c₀), bulk modulus (B₀), and its first-pressure derivative (B?) have been evaluated in both paramagnetic and ferromagnetic phases. The electronic results of the tetragonal BeTiTe₂ compound show a complete half-metallic behaviour. Moreover, the computed total magnetic moment of this compound is close to 4 μ_B, confirming its half-metallic ferromagnetic nature.     

Fenestranes in Synthesis: Unique and Highly Inspiring Scaffolds

The scaffold of fenestranes is quite unique, as it contains four condensed cycles and a distorted tetracoordinated central carbon atom with bond angles greater than the regular 109°28“. In this Minireview, a detailed overview on the developments regarding this compound class, including their synthesis, is given for the time period since 2006. In the past years, natural products that belong to the class of heterofenestranes have been isolated and their syntheses will also be discussed.     

Flavonoid-DNA binding studies and thermodynamic parameters

Interactional studies of new flavonoid derivatives (Fl) with chicken blood ds.DNA were investigated spectrophotometrically in DMSO-H2O (9:1 v/v) at various temperatures. Spectral parameters suggest considerable binding between the flavonoid derivatives studied and ds.DNA. The binding constant values lie in the enhanced-binding range. Thermodynamic parameters obtained from UV studies also point to strong spontaneous binding of Fl with ds.DNA. Viscometric studies complimented the UV results where a small linear increase in relative viscosity of the DNA solution was observed with added optimal flavonoid concentration. An overall mixed mode of interaction (intercalative plus groove binding) is proposed between DNA and flavonoids. Conclusively, investigated flavonoid derivatives are found to be strong DNA binders and seem to be promising drug candidates like their natural analogues.     

Chemical composition and antioxidant activity of aerial parts of Ferula longipes Coss. ex Bonnier and Maury

This is the first study on the phytochemistry and antioxidant activity of Ferula longipes Coss. ex Bonnier and Maury (Apiaceae). A new flavonoid quercetin-3-O-α-L-rhamnopyranoside-7-O-ß-D-[2-O-caffeoyl]-glucopyranoside (1), along with 10 known compounds kaempferol-3-O-α-L-rhamnopyranoside (2), quercetin-3-O-α-L-rhamnopyranoside (3), kaempferol-3-O-ß-D-glucopyranoside-7-O-α-L-rhamnopyranoside (4), isorhamnetin-3-O-α-L-rhamnopyranoside-7-O-ß-D-glucopyranoside (5), quercetin-3-O-α-L-rhamnopyranoside-7-O-ß-D-glucopyranoside (6), isorhamnetin-3,7-di-O-β-D-glucopyranoside (7), apigenin (8), apigenin-7-O-ß-D-glucopyranoside (9), 3,5-dicaffeoylquinic acid (10), deltoin (11) were isolated from the aerial parts of Ferula longipes Coss. Structures elucidation was performed by comprehensive 1D and 2D NMR analyses, mass spectrometry and by comparison with literature data. The compounds 1, 3, 4, 6, 7 and 10 were evaluated for their antioxidant activity, compound 1 exhibited the best antiradical activity potential and showed IC₅₀ and A_0.5 values 5.70, 7.25, 5.00, and 2.63 μg/mL towards DPPH free radical-scavenging, ABTS, CUPRAC, and reducing power assays, respectively compared with BHA, BHT and ascorbic acid which were used as positive controls.     

Reactions in aminosilane–epoxy prepolymer systems I. Kinetics of epoxy–amine reactions

The reactions of an epoxy prepolymer based on bisphenol A diglycidylether (DGEBA) with γ-aminopropyltriethoxysilane (γ-APS) are studied. The results of different techniques are compared: size exclusion chromatography, differential scanning calorimetry, chemical titration, and Fourier Transform Infrared absorption. Epoxy amine reactions are shown to be faster than the crosslinking reactions between alkoxysilane and hydroxy groups, and thus, can be studied seprately. The reactivity of the epoxy group in DGEBA is compared with that of phenylglycidylether (PGE). And the reactivity of the amine group of γ-APS is compared with that of hexylamine. The kinetic constants are calculated with a mechanism which takes into account both the catalytic and noncatalytic reactions. The ratio r = k₂/k₁ of the reactivity of the secondary to the primary amino-hydrogens was also determined. The values of r are 1.4 for hexylamine and 1.2 for γ-APS. The reactivity of the epoxy groups are the same for both PGE and DGEBA.     

Polar [3 + 2] cycloaddition of ketones with electrophilically activated carbonyl ylides. Synthesis of spirocyclic dioxolane indolinones

The [3 + 2] cycloaddition reaction between carbonyl ylides generated from epoxides and ketones (ethyl pyruvate, ethyl phenylglyoxylate, isatin, N-methylisatin and 5-chloroisatin) to give substituted dioxolanes and spirocyclic dioxolane indolinones was investigated. The effect of microwave irradiation on the outcome of the reaction was studied. The thermal reaction between 2,2-dicyano-3-phenyloxirane and N-methylisatin was theoretically studied using DFT methods. This reaction is a domino process that comprises two steps. The first is the thermal ring opening of the epoxide to yield a carbonyl ylide intermediate, whereas the second step is a polar [3 + 2] cycloaddition to yield the final spiro cycloadducts. The cycloaddition presents a low stereoselectivity and a large regio- and chemoselectivity. Analysis of the electrophilicity values and the Fukui functions of the reagents involved in the cycloaddition step allowed the chemical outcome to be explained.     

Effect of pulegone and pulegone oxide on the corrosion of steel in 1?M HCl

The inhibitive action of pulegone and pulegone oxide toward acid corrosion of steel in molar hydrochloric acid was studied by weight loss measurements, potentiodynamic polarization, and impedance spectroscopy (EIS) methods. The pulegone is extracted starting from oil of Pennyroyal Mint (Mentha pulegium). The natural compound was found to delay the corrosion rate. The pulegone oxide is prepared by oxidation of pulegone. The inhibition efficiency was found to increase with the inhibitor content to attain 81 and 75% at 5 g dm⁻³ for pulegone and pulegone oxide. The increase in temperature leads to an increase in the inhibition efficiency of the natural compared.