Neuroprotective Potential of Chrysin: Mechanistic Insights and Therapeutic Potential for Neurological Disorders

Chrysin, a herbal bioactive molecule, exerts a plethora of pharmacological effects, including anti-oxidant, anti-inflammatory, neuroprotective, and anti-cancer. A growing body of evidence has highlighted the emerging role of chrysin in a variety of neurological disorders, including Alzheimer’s and Parkinson’s disease, epilepsy, multiple sclerosis, ischemic stroke, traumatic brain injury, and brain tumors. Based on the results of recent pre-clinical studies and evidence from studies in humans, this review is focused on the molecular mechanisms underlying the neuroprotective effects of chrysin in different neurological diseases. In addition, the potential challenges, and opportunities of chrysin’s inclusion in the neurotherapeutics repertoire are critically discussed.     

Synthesis and characterization of a novel polyazomethine ether for NLO application

Polymer containing azomethine and ether linking groups between phenylene rings has been prepared. It is a polycondensation reaction of a single monomer containing nitro as well as hydroxyl group in p,p^′ position from 4-nitroaniline and 4-hydroxy benzaldehyde. The polymer has been characterized by elemental analysis, IR, UV and NMR spectroscopies, viscometry and thermal studies. The thermotropic liquid crystalline behaviour of the polymer is investigated by optical polarizing microscopy. The crystalline behaviour of the polymer is confirmed by XRD study. The polymer shows good second harmonic generation for non-linear optical application.     

Effect of TiO2 on electron paramagnetic resonance, optical transmission and dc conductivity of vanadyl doped sodium borate glasses

Glass systems with composition xTiO2.(30 - x)Na2O.70B2O3 (series I) and xTiO2.(70 - x)B2O3.30Na2O (series II) containing 2 mol% V2O5 have been prepared (0 < or = x < or = 7, mol%) by normal melt-quenching. The electron paramagnetic resonance (EPR) spectra of VO2+ ions have been recorded in the X-band (approximately 9.13 GHz) at room temperature. Spin Hamiltonian parameters, gparallel, gperpendicular, Aparallel, Aperpendicular, the dipolar hyperfine coupling parameter (P) and the Fermi contact interaction parameter (K) have been calculated. The increase in Deltagparallel/Deltagperpendicular with increase in TiO2 content in series I shows that the octahedral symmetry of V4+O6 complex is reduced, whereas in series II the octahedral symmetry is improved with increase in x. The decrease in P, in both the series, indicates that the 3dxy orbit expands with increase in mol% of TiO2. The molecular orbital coefficients, alpha2 and gamma2 have been calculated by recording the optical transmission spectra in the range 500-850 nm. alpha2 and gamma2 increase with increase in x in both the series, which indicates that, the covalency of the vanadium oxygen bonds decreases. The dc conductivity sigma, decreases and activation energy, W increases with increase in TiO2:Na2O ratio whereas with increase in TiO2:B2O3 ratio the variation in sigma and W is within experimental error.     

Optical band gap studies and estimation of two photon absorption coefficient in alkali bismuth borate glasses

The optical absorption spectra of the glasses with composition xBi₂O₃·(30???x)R₂O·70B₂O₃ (R?Li, Na, K) and xBi₂O₃·(70???x)B₂O₃·30Li₂O (0?≤?x?≤?20) have been recorded in the wavelength range 350–650?nm. The glass samples were prepared by the normal melt–quench technique. The fundamental absorption edge for all the series of glasses is analyzed using the theory of Davis and Mott. The position of absorption edges and the values of optical band gap are dependent on the mol% of Bi₂O₃. The absorption in these glasses is associated with indirect transitions. The values of Urbach's energy and band tailing parameters are reported. The two photon absorption coefficient, β, in these glasses has also been estimated from the optical band gap and its value ranges from 1.3 to 11.6?cm/GW. The relationship between β and glass composition has also been discussed in terms of the electronic structure of the glass system.     

Tandem Michael addition of amines to maleic anhydride and 1,3-prototropic shift: experimental and theoretical results

Amines, namely diethylamine, diphenylamine, benzylamine, and pyrrolidine react with maleic anhydride to form Michael adducts. The Michael adducts formed with the first three amines undergo tandem 1,3-prototropic shift to give the final products. Computational calculations at the DFT (B3LYP/6-31+G*) level reveal that a reactant-complex formed between the initially formed Michael adduct and the respective amine plays a crucial role in the 1,3-prototropic shift. In the reaction of pyrrolidine with maleic anhydride, Michael addition is not followed by 1,3-prototropic shift. The theoretical studies of the latter reaction show that a reactant-complex is not formed in this case. Dimethyl maleate and dimethyl fumarate react with pyrrolidine to give the same Michael addition product.     

Synthesis of new chrysin derivatives with substantial antibiofilm activity

Molecular Diversity - Multidrug resistance mechanism of microorganisms towards conventional antimicrobials nowadays faces a common health problem. So, searching and development of new...     

Persulfurated Benzene-Cored Asterisks with π-Extended ThioNaphthyl Arms: Synthesis,Structural, Photophysical and Covalent Dynamic Properties

The synthesis of regioisomeric asterisks ( 5 ) and ( 6 ) incorporating a benzene core with six 1-naphthylthio or six 2-naphthylthio arms are reported in search for new materials with optoelectronic properties. The consequences on the extension of a π system surrounding a persulfurated benzene core provide a new avenue to study the structural, photophysical, and chemical properties of such family of all-organic phosphors. It also diverts the persulfuration mechanism after two radical cyclizations for making a [5]dithiohelicene by-product ( 7 ) and favors dynamic sulfur component exchange reactions surrounding the core. These exchanges convert asterisks ( 5 ) and ( 6 ), non-phosphorescent at 20 °C to the highly phosphorescent ( 4 ) (ϕ ∼100 %, solid state at 20 °C). For asterisks ( 5 ) and ( 6 ), the absence of the typical phosphorescence of the per(phenylthio)benzene core in the solid state at 20 °C and the presence of a weak naphthalene-based phosphorescence at 77 K is attributed to an energy transfer from the triplet state of the persulfurated benzene core to the outer naphthalene moieties, resulting in an antenna system.     

Shape-memory effect in PMN-PT(65/35) ceramic

We report the observation of fairly large and fully recoverable shape-memory strain in thin bars of lead magnesium niobate lead titanate ceramic for a composition (65/35) near its morphotropic phase-boundary. The recoverable shape strain produced by bending and thermal-cycling experiments is ∼0.3%, similar in magnitude to that reported for the shape-memory effect (SME) observed in some other dielectric ceramics. An explanation of the observed SME and the recoverable shape-strain is given in terms of the ferroelastic phase transitions, and the availability of a large number of competing phases and domain states near the morphotropic phase boundary in this material. The stress-induced shifting of the temperatures at which the ferroelastic phase transitions occur also plays an important role in ensuring good crystallographic reversibility around the thermal-cycling experiments.     

Magnetocaloric effect in DyCu2

The magnetocaloric effect of the rare-earth intermetallic compound DyCu₂ is explored through magnetization measurements. DyCu₂ is paramagnetic at the room temperature but becomes antiferromagnetic below 27 K (Neel temperature). Strong temperature and field dependence of magnetization in DyCu₂ at and around the Neel temperature lead to a large magnetocaloric effect. An appreciable magnetocaloric effect persists well above the Neel temperature probably because of the presence of short-range ferromagnetic correlations in the paramagnetic state of DyCu₂. This along with the absence of magnetic hysteresis lead to a large effective refrigerant capacity of 194 J/kg below 44 K, which makes the material important as a potential magnetic refrigerant for the cryogenic liquefier cycles.