Three new furoquinoline alkaloids from the leaves of Boninia glabra

Three novel furoquinoline alkaloid oxogeranyl ethers (1-3) and one known furoquinoline alkaloid (4) were isolated from the leaves of Boninia glabra, an endemic plant of the Bonin Islands. Their structures were elucidated on the basis of spectroscopic analysis.     

Organic semiconductors based on small molecules with thermally or photochemically removable groups

Solution processable organic semiconducting small molecules are desirable for the manufacture of low-cost, large-area electronic products on flexible substrates. This article provides an overview of recent progress in OFETs based on solution processable small molecules that can be converted to insoluble organic semiconducting materials on films by thermal or photochemical removal of leaving groups after fabrication of the film.     

Acenaphthylene‐Fused Cyclo[8]pyrroles with Intense Near‐IR‐Region Absorption Bands

An acenaphthylene‐fused cyclo[8]pyrrole was synthesized by using an oxidative coupling reaction of the corresponding 2,2′‐bipyrrole. Two conformational isomers 1 a and 1 b were isolated, and their molecular structures were elucidated by X‐ray crystallographic studies. The less‐polar and lower‐symmetry 1 b isomer can be converted into the 1 a isomer through a thermal ring flip. Application of the perimeter model developed by Michl to magnetic circular dichroism spectroscopic data and theoretical calculations demonstrate that there is a marked redshift of the near‐IR absorption maxima relative to cyclo[8]isoindole because there is a significant stabilization of the LUMO due to the differing effects of a fused ring expansion with acenaphthylene and benzene moieties on the frontier π molecular orbitals.     

Characterization of the molecular reorientational dynamics of the neat ionic liquid 1-butyl-3-methylimidazolium bromide in the super cooled state using 1H and 13C NMR spectroscopy

The (13)C spectra and (13)C longitudinal relaxation times (T(1)) were measured to investigate the segmental motion of the neat ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) in the super cooled state. The (13)C signals of the imidazole ring significantly broadened at 283 K, whereas many other signals were unchanged. In the process of lowering temperature, the [bmim]Br changed to the solid state at ca 273 K without showing the rapid phase transition. Only the (13)C signal of the terminal methyl group in the butyl chain was still observed at 263 K, indicating that the motion of the imidazole ring was extremely restricted, whereas the methyl group in the butyl chain was active even in the solid state. The (13)C-T(1) values measured as a function of temperature also supported the discrete segmental motions of the [bmim](+) cation.     

2-Aryl-1,4-naphthoquinone-1-oxime methyl ethers: their cytotoxic activity

Preliminary examination for the structure-activity relationship of quinone monooxime derivatives on cytotoxicity against HeLa S3 cell and further trials using eight different cell lines suggested that 2-aryl-6,7-methylenedioxy-1,4-naphthoquinone-1-oxime methyl ethers, carrying 2-methoxy-4,5-methylenedioxyphenyl, 7-methoxy-2-methylbenzofuran-4-yl, and 2-methoxycarbonyl-3,4-dimethoxyphenyl as the 2-aryl substituent, were potential candidates for anti-cancer drugs.     

Antitumor effect of liposomal histone deacetylase inhibitor-lipid conjugates in vitro

Histone deacetylase inhibitor (HDACI), suberoylanilide hydroxamic acid (SAHA), approved by the Food and Drug Administration (FDA) for the treatment of cutaneous T cell lymphoma, is a promising new treatment strategy for various cancers. In this study, we hypothesized that a liposomal formulation of HDACI might efficiently deliver HDACI into tumors. To incorporate HDACI efficiently into the liposomal membrane, we synthesized six HDACI-lipid conjugates, in which polyethylene glycol(2000) (PEG(2000))-lipid or cholesterol (Chol) was linked with a potent hydroxamic acid, HDACI, SAHA or K-182, by cleavable linkers, such as ester, carbamide and disulfide bonds. Liposomal HDACI-lipid conjugates were prepared with distearoylphosphatidylcholine (DSPC) and HDACI-Chol conjugate or with DSPC, Chol and HDACI-PEG-lipid conjugates, and their cytotoxicities were evaluated for human cervix tumor HeLa and mouse colon tumor Colon 26 cells. Among the liposomes, liposomal oleyl-PEG(2000)-SAHA conjugated with SAHA and oleyl-PEG(2000) via a carbamate linker showed higher cytotoxicity via hyperacetylation of histone H3 and induction of caspase 3/7 activity. These results suggested that liposomal HDACI-lipid conjugates may be a potential tool for cancer therapy.     

Synthesis of uniform and dispersive calcium carbonate nanoparticles in a protein cage through control of electrostatic potential

We have synthesized calcium carbonate nanoparticles (Ca-NPs) in the cavity of a cage-shaped protein, apoferritin, by regulating the electrostatic potential of the molecule. The electrostatic potential in the cavity was controlled by pH changes resulting from changes in the dissolved carbon dioxide (CO(2)) concentration in the reaction solution. Recombinant L-apoferritin was mixed with a suspension of calcium carbonate (CaCO(3)), and the mixture was pressurized with gaseous CO(2) at 2 MPa. The pH of the solution decreased from 9.3 to 4.4; the CaCO(3) dissolved during pressurization, and then precipitated after the pressure was reduced to ambient. After repeating the pressurization/depressurization process three times, about 70% of the apoferritin molecules were found to contain nanoparticles with an average diameter of 5.8 ± 1.2 nm in their cavity. Energy-dispersive X-ray spectroscopy and electron diffraction analysis showed that the nanoparticles were calcite, one of the most stable crystal forms of CaCO(3). Electrostatic potential calculations revealed a transition in the potential in the apoferritin cavity, from negative to positive, below pH 4.4. The electrostatic potential change because of the change in pH was crucial for ion accumulation. Since the Ca-NPs synthesized by this method were coated with a protein shell, the particles were stably dispersed in solution and did not form aggregates. These Ca-NPs may be useful for medical applications such as synthetic bone scaffolds.     

Liposome solubilization induced by surfactant molecules in a microchip

The dynamics of liposome solubilization was monitored by dynamic light scattering and optical microscopy. A newly designed Y-shape microchannel connected to a room was incorporated into a microchip and the reaction processes of the liposome suspension and surfactant solution were observed in the room after mixing the two fluids and stopping the flow. By using this microchip, we succeeded in real-time monitoring of liposome solubilization and the following dynamic processes of solubilization were proposed: 1) Deformed liposomes become spherical. 2) The liposome size increases until the surfactant/liposome ratio in the liposome membrane reaches a threshold value. 3) Mixed micelles of surfactants and phospholipids are released and the liposomes collapse.