Synthesis and Investigation of Flavanone Derivatives as Potential New Anti-Inflammatory Agents

Flavonoids are polyphenols with broad known pharmacological properties. A series of 2,3-dihydroflavanone derivatives were thus synthesized and investigated for their anti-inflammatory activities. The target flavanones were prepared through cyclization of 2′-hydroxychalcone derivatives, the later obtained by Claisen–Schmidt condensation. Since nitric oxide (NO) represents an important inflammatory mediator, the effects of various flavanones on the NO production in the LPS-induced RAW 264.7 macrophage were assessed in vitro using the Griess test. The most active compounds were flavanone (4G), 2′-carboxy-5,7-dimethoxy-flavanone (4F), 4′-bromo-5,7-dimethoxy-flavanone (4D), and 2′-carboxyflavanone (4J), with IC50 values of 0.603, 0.906, 1.030, and 1.830 µg/mL, respectively. In comparison, pinocembrin achieved an IC₅₀ value of 203.60 µg/mL. Thus, the derivatives synthesized in this work had a higher NO inhibition capacity compared to pinocembrin, demonstrating the importance of pharmacomodulation to improve the biological potential of natural molecules. SARs suggested that the use of a carboxyl-group in the meta-position of the B-ring increases biological activity, whereas compounds carrying halogen substituents in the para-position were less active. The addition of methoxy-groups in the meta-position of the A-ring somewhat decreased the activity. This study successfully identified new bioactive flavanones as promising candidates for the development of new anti-inflammatory agents.     

Four new colchicinoids, gloriosamines A-D, from Gloriosa rothschildiana

Four new colchicinoids, gloriosamines A-D, were isolated from the aerial parts of Gloriosa rothschildiana. The structure of gloriosamine A, including the absolute configuration, was determined by chemical conversion from colchicine.     

Effect of pH on the Enantiospecificity of Homocysteine Monolayer on Au(111) for the Redox Reaction of 3,4‐Dihydroxyphenylalanine

The effect of pH on the enantiospecificity of Au (111) electrode modified with L ‐homocysteine was evaluated for the electrochemical redox reaction of 3,4‐dihydroxyphenylalanine (DOPA). Cyclic voltammetric peaks clearly exhibited enantiospecificity at pH 0.6 and 2, whereas no enantiospecificity was observed at pH 3, 4, and 5.5. Scanning tunneling microscopy confirmed the highly ordered (2√3×3√3)R30° structure of L ‐homocysteine at pH 0.6, at which L ‐homocysteine molecules form a dimer through the hydrogen‐bond between carboxy groups (COOH), while a disordered structure was observed at pH 5.5. These results suggest that the dimer formed in the acidic solutions at pH below 3 plays an important role in providing the enantiospecificity to the Au(111) surface.     

Synthesis and properties of hexakis(6-octyl-2-azulenyl)benzene as a multielectron redox system with liquid crystalline behavior

[structure: see text] This paper describes the cyclotrimerization reaction of di(2-azulenyl)acetylenes (2a,b) catalyzed by Co2(CO)8 to produce hexa(2-azulenyl)benzene derivatives (1a,b). The cyclooligomerization of 2a and 2b utilizing CpCo(CO)2 as a catalyst produced (eta5-cyclopentadienyl)[tetra(2-azulenyl)cyclobutadiene]cobalt complexes (3a,b). The redox behavior of hexakis(6-octyl-2-azulenyl)benzene (1b), bis(6-octyl-2-azulenyl)acetylene (2b), and the cobalt complexes 3a and 3b along with 6-octyl-2-phenylazulene (19) was examined by cyclic voltammetry (CV). The reduction of compound 1b exhibited multiple-electron transfers in one step upon CV with a reduction potential similar to that of compound 19. However, the CVs of compounds 2b, 3a, and 3b were characterized by stepwise waves because of the reduction of each azulene ring. The mesomorphic behaviors of 1b, 2b, and 19 were also studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD) techniques. A new series of azulene derivatives, 1b, 2b, and 19, substituted by a long alkyl chain at the 6-position shows mesomorphism with crystalline polymorphs. Compound 1b showed a large temperature range of hexagonal columnar mesophases (Col(ho)) from 115.5 to 199.9 degrees C. Compound 2b has rectangular columnar (Col(ro)), smectic E (S(E)), and nematic (N) mesophases. Compound 19 exhibited an S(E) mesophase.     

An ab initio study of tunneling splittings in the water trimer

Tunneling splittings in the water trimer have been determined by the semiclassical WKB method, based on pathways characterized at the computational level of second-order M?ller-Plesset theory with basis sets of aug-cc-pVTZ quality. This calculation takes into account the single-flip and bifurcation tunneling rearrangements of the water trimer. The predicted splittings are 37.93 cm(-1) for the flip and 6.50x10(-3) cm(-1) for bifurcation, which agree quite well with the corresponding experimental values of 43.52 cm(-1) and 9.63x10(-3) cm(-1).     

Thermal reaction of β-carotene. Part 1

β-Carotene has ben heated under vacuum at temperatures ranging from 200 to 350°C for 24 h as a model of geothermal reaction of carotenoids in sediments and of a thermal reaction of highly conjugated polyene. Compounds with molecular weights of 138, 240, 346 and 444 and isomers of β-carotene were obtained in addition to toluene, xylene, ionene and 2,6-dimethylnaphthalene, which have been reported previously as pyrolysis products of β-carotene. Possible reaction mechanisms for the formation of the pyrolysis products are given.     

Single-walled carbon nanotubes acquire a specific lectin-affinity through supramolecular wrapping with lactose-appended schizophyllan

Single-walled carbon nanotubes can be entrapped within a helical superstructure composed of schizophyllan bearing lactoside-appendages to show an excellent water-solubility as well as a specific lectin-affinity.     

Lactose-appended schizophyllan is a potential candidate as a hepatocyte-targeted antisense carrier

A schizophyllan (beta-1,3-glucan) derivative carrying lactose-appendages prepared by reductive amination can form stable macromolecular complexes with polynucleotides, shows excellent affinity with a lactose-binding lectin, and effectively mediates gene transfection into hepatocytes.     

Enantioselective crystal growth of leucine on a self-assembled monolayer with covalently attached leucine molecules

Enantioselective crystal growth of leucine occurs on a solid surface modified with a self-assembled monolayer depending on the chirality of the enantiomer attached, as evidenced by the X-ray diffraction method.     

Collision-induced dissociation actualized the H+-promoted reaction as observed in vitro; harman formation from beta-carboline-type monoterpenoid glucoindole alkaloids

The fragmentation from beta-carboline-type monoterpenoid glucoindole alkaloids to harman, which is a hypothetical pathway to generate simple beta-carbolines, was actualized in the collision-induced dissociation in MS.