Schizonticidal antimalarial sesquiterpene lactones from Magnolia champaca (L.) Baill. ex Pierre: microwave-assisted extraction,HPTLC fingerprinting and computational studies

The present study explored the schizonticidal potential of traditionally used Magnolia champaca (L.) Baill. ex. Pierre flowers, identifying constituents of interest. The extraction of phytoconstituents was carried out by microwave-assisted technique, isolated via column chromatography, and characterised by various physicochemical, spectral (IR, 1H-NMR and Mass) and chromatographic (HPTLC) techniques. Both the isolated compounds (parthenolide and costunolide diepoxide) exhibited potent schizonticidal antimalarial activity during primary screening in rodent models, with maximum parasitaemia suppression (85.18% and 83.65%, respectively) at a dose of 20 mg/kg body weight when compared to the standard drugs chloroquine and artesunate. In silico techniques were employed to identify the probable biological target and mechanism of action of these isolated compounds. Molecular docking studies also predicted the binding orientations and multi-targeted action of these compounds, in particular costunolide diepoxide with maximum affinity towards SERCA and DHFR proteins. Additionally, favourable in silico ADMET parameters were envisaged through various computational programmes.     

Optoelectronic properties of benzotrithiophene isomers: A density functional theory study

Benzotrithiophene (BTT) isomers were investigated using density functional theory (DFT) and time‐dependent DFT (TD‐DFT) with the aim to explore their structures, linear optical properties, vertical and adiabatic ionization potentials (IP_v and IP_a), electron affinities (EA_v and EA_a), and reorganization energies (λ). The computed bond lengths and bond angles at the B3LYP/6–311+G (d, p) level of theory are in good agreement with experimental crystal structures of the known BTTs. These molecules are planar with zero dihedral angle, making them an ideal backbone for high charge mobility. The UV–visible spectra of BTT isomers are in the range 280–360 nm. All BTT isomers have low hole/electron reorganization energies, which is the main characteristic of good hole/electron transporting materials, and these isomers in turn have potential applications in the field of organic materials.     

Amberlite IR-120 catalysed efficient synthesis of glycosyl enamines and their application

β-Keto esters and acetyl acetone on condensation with glycosylated amino esters in the presence of IR-120 resin resulted in high yields of glycosyl enamino esters or ketones. The latter on cyclisation with NaH in toluene at reflux gave 6-glycosyl-5,6-dihydro-1H-pyridin-4-ones in fair to good yields.     

Selectivity for Cs and Sr in Nb-substituted titanosilicate with sitinakite topology

The 25% niobium substituted crystalline titanosilicate with the composition Na_1.5Nb_0.5Ti_1.5O₃SiO₄·2H₂O (Nb-TS) was synthesized under hydrothermal conditions. Its selectivity for radioactive ¹³⁷Cs and ⁸⁹Sr was compared with the TS, Na₂Ti₂O₃SiO₄·2H₂O, having sitinakite topology. The Nb-TS shows significantly higher uptake value for ¹³⁷Cs but lower for ⁸⁹Sr than the TS. To investigate the origin of selectivity, the ion exchanged Cs⁺ and Sr²⁺ forms with the composition, Cs_xNaH_yNb_0.5Ti_1.5O₃SiO₄·zH₂O (x=0.1, 0.2 and 0.3, x+y=0.5 and z=1-2) and Sr_0.2Na_0.6H_0.5Nb_0.5Ti_1.5O₃SiO₄·H₂O, respectively, were structurally characterized from the X-ray powder diffraction data using the Rietveld refinement technique. Simultaneously the kinetics of ¹³⁷Cs and ⁸⁹Sr uptake was investigated for the Nb^V free and doped samples. While the Cs⁺ and Sr²⁺ exchanged form of Nb-TS and the Cs⁺ exchanged form of TS retain the symmetry of the parent compound, the Sr²⁺ exchanged form of TS undergoes a symmetry change. The differences in the uptake of Cs⁺ and Sr²⁺ result from the different coordination environments of cesium and strontium in the eight-ring channel, that result from various hydration sites in the tunnel. The origin of selectivity appears to arise from the higher coordination number of cesium or strontium. Other effects due to Nb^V substitution are reflected in the increase of both, the a- and c-dimensions and thus the unit cell volume, and the population of water vs. Na⁺ in the channel to charge-balance the Nb⁵⁺↔Ti⁴⁺ substitution.     

Enhanced dielectric and electro-optical properties of a newly synthesised ferroelectric liquid crystal material by doping gold nanoparticle-decorated multiwalled carbon nanotubes

In this article, a newly synthesised ferroelectric liquid crystal (FLC) material, namely LAHS 22, has been characterised. The characterisation of the FLC material has been performed using dielectric relaxation spectroscopy, differential scanning calorimetry and polarisation optical microscopy. We observed an enhancement in the dielectric and electro-optical properties of the FLC material by incorporating gold nanoparticles (GNPs)-decorated multiwalled carbon nanotubes (MWCNTs). The GNPs-decorated MWCNTs cause an increment in dielectric dispersion (up to kHz), absorption, spontaneous polarisation and rotational viscosity of the FLC material. The pure and GNPs-decorated MWCNTs doped FLC cells were analysed by means of various dielectric spectroscopic and optical measurements. The observed enhancement in the dielectric and electro-optical properties of the FLC material has also been studied with concentration of GNPs-decorated MWCNTs in FLC material. The GNPs-decorated MWCNTs/FLC composites are not only of fundamental importance, but also useful materials for device applications such as liquid crystal displays and memory devices.     

Synthesis,characterization, molecular docking and biological activity of 5,6-bis-(4-fluoro-phenyl)-3,4,7,8-tetraaza-bicyclo[8.3.1]tetradeca-1(13),4,6,10(14),11-pentaene-2,9-dione and its transition metal complexes

Macrocyclic Schiff base ligand through the condensation of 1,3-dicarbonyl-phenyl-dihydrazide with 4,4′-difluorobenzil and its Co(II), Ni(II), Cu(II) and Zn(II) metal complexes have been synthesized. The ligand and metal complexes were characterized by analytical and physicochemical methods. An octahedral geometry arising from coordination of N2O2 donor atoms from the macrocyclic framework has been proposed for all metal complexes. Synthesized ligand and metal complexes were investigated for in vitro antibacterial and antioxidant activity. Complex [Ni(C₂₂H₁₄N₄F₂O₂)(OCOCH₃)₂] has shown remarkable antibacterial activity (Minimum inhibitory concentration 8–16?μg/ml) comparable to commercial antibiotic Ciprofloxacin. Anticancer activity of synthesized compounds against Squamous Cell Carcinoma (SCC4), head and neck cancer cell line has also been studied at different concentrations and at different time points. Complexes [Co(C₂₂H₁₄N₄F₂O₂)(NO₃)₂] and [Cu(C₂₂H₁₄N₄F₂O₂)(OCOCH₃)₂] have shown remarkable anticancer results (IC₅₀ 31.1 and 43.1?μM) against the tested cell line in concentration dependent manner. Molecular docking studies were carried out to find the binding mode of the synthesized macrocyclic Schiff base ligand to Epidermal Growth Factor Receptor (EGFR) Kinase (PDB ID: 1M17).     

Observation of double radiative capture on pionic hydrogen

We report the first observation of double radiative capture on pionic hydrogen. The experiment was conducted at the TRIUMF cyclotron using the RMC spectrometer and detected gamma-ray coincidences following pi(-) stops in liquid hydrogen. We found the branching ratio for double radiative capture to be [3.05+/-0.27(stat)+/-0.31(syst)]x10(-5). The measured branching ratio and angle-energy distributions support the theoretical prediction of a dominant contribution from the pipi-->gammagamma annihilation mechanism.     

Angular momentum and cross sections for fusion with weakly bound nuclei: breakup,a coherent effect

Results for the cross section and average angular momentum for complete fusion at energies around the Coulomb barrier are presented for 7Li with 165Ho. Comparison of the cross sections with a one-dimensional barrier penetration model, using a potential consistent with the measured elastic scattering, showed a reduction above the barrier and an enhancement below it. An increase in the measured average angular momentum, , above the barrier and its consistency with that obtained from the fusion excitation function for weakly bound nuclei, is reported. These results together with a reanalysis of existing data conclusively demonstrate that the effect of breakup on fusion is coherent, like coupling to any nonelastic channel.