[Show abstract][Hide abstract] ABSTRACT: A phytochemical investigation of Inula falconeri, a plant endemic to the Himalayas, afforded 10 new sesquiterpenoids and 26 known sesquiterpene lactones, including those bearing guaiane, pseudoguaiane, xanthane, eudesmane, germacrane, rare secocaryophyllane, chromolaevane, and carabrane frameworks. The structures were elucidated via spectroscopic analysis and compared with data from literature. All the isolates were assessed for their inhibitory effects against LPS-induced nitric oxide production in RAW264.7 macrophages. Compounds 4, 11, 24, and 31 showed stronger inhibitory activities than the positive control with IC(50) values of 0.13, 0.07, 0.11, and 0.11 μM, respectively. These studies also led to a better understanding of the structure-activity relationships for the sesquiterpene lactone family of compounds.
European Journal of Medicinal Chemistry 09/2011; 46(11):5408-15. DOI:10.1016/j.ejmech.2011.08.047 · 3.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Eight new pseudoguaianolides (1-8), two new guaianolides (9 and 10), and 14 known sesquiterpenes were isolated from the aerial parts of Inula hupehensis. The structures were elucidated using spectroscopic methods and circular dichroism analysis. All compounds were tested for inhibitory activities against LPS-induced nitric oxide production in RAW264.7 macrophages. Compounds 13 and 22 were found to inhibit nitric oxide production potently, with IC50 values of 0.9 and 0.6 μM, respectively. Preliminary structure-activity relationships for these compounds are proposed.
[Show abstract][Hide abstract] ABSTRACT: Twenty-two new sesquiterpenes were isolated from the aerial parts of Inula japonica Thunb., together with fifteen known ones. Their structures were determined by detailed spectroscopic analysis, X-ray diffraction studies, and modified Mosher method. All 37 compounds were evaluated for the inhibition of LPS-induced nitric oxide (NO) production in RAW264.7 macrophages, and most of isolates significantly inhibited the NO production with IC50 values in the range of 3.5–20 μM. Besides, results obtained in our studies provided a structure–activity relationship that would be used to design anti-inflammatory agents in the future.Graphical abstractTwenty-two new sesquiterpenes were isolated from the aerial parts of Inula japonica Thunb., together with fifteen known ones.
[Show abstract][Hide abstract] ABSTRACT: Three new phenylpropanoid compounds, named nervolans A–C (1–3, resp.), together with two other known phenylpropanoids, coniferyl diangelate and sinapyl diangelate, were isolated from the aerial parts of Inula nervosaWall. (Asteraceae), a traditional Chinese medicinal plant. The structures of 1–3 were elucidated by detailed spectroscopic analyses, including HR-ESI-MS data and 2D-NMR spectroscopy. Compounds 1–5 exhibited mild inhibitory effects against NO production in LPS-stimulated RAW264.7 cells.
[Show abstract][Hide abstract] ABSTRACT: Eight new dimeric sesquiterpene lactones (japonicones E-L, 1- 8), including a novel sesquiterpene dimer bearing a rare hydroperoxide group (japonicone E, 1), were isolated from the aerial part of Inula japonica Thunb. Their structures were determined mainly by the use of 1D and 2D NMR spectroscopic techniques including HSQC, (1)H-(1)H COSY, HMBC, and NOESY. All the isolates were tested for inhibitory effects against LPS-induced NO production in RAW264.7 macrophages. Among the compounds tested, japonicone F (2) showed the strongest activity with the IC(50) value of 4.1 microg/mL.
[Show abstract][Hide abstract] ABSTRACT: A new ent-kaurane type diterpenoid glycoside, 17-O-beta-D-glucopyranosyl-16alpha-ent-kauran-19-oic acid (1), together with 17-hydroxy-16alpha-ent-kauran-19-oic acid (2), 16alpha,17-dihydroxyl-ent-kauran-19-oic acid (3), and 16alpha-hydroxy-17-acetoxy-ent-kauran-19-oic acid (4) were isolated from the aerial parts of Inula japonica Thunb. The structure of 1 was determined mainly by use of 1D and 2D NMR spectroscopic techniques including HSQC, (1)H-(1)H COSY, HMBC, and NOESY. In addition, 4 exhibited significant inhibitory activity on NO production in LPS-stimulated RAW264.7 cells with IC(50) value of 14.3 microg/mL.
Archives of Pharmacal Research 10/2009; 32(10):1369-72. DOI:10.1007/s12272-009-2004-5 · 2.05 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Novel polyurethane (PU) composites were prepared, based on hybrid inorganic/organic phosphazene-containing microspheres. The FT-IR spectra have shown that the microspheres have been linked with PU matrix. The microstructure of the composites is investigated by SEM. In comparison with PU, the glass transition temperatures and thermal stability of the composites are increased. The results from tensile testing of the composites have indicated that tensile strength is improved and elongation at break is almost invariable. The investigation on the surface properties of the composites showed that the water contact angles are obviously increased by adding 2 and 4 wt.-% microspheres to the matrix. 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
[Show abstract][Hide abstract] ABSTRACT: Highly cross-linked microspheres bearing active amino groups on the surface have been successfully synthesized via a single-step precipitation polymerization of hexachlorocyclotriphosphazene (HCCP) with 4,4'-diaminodiphenyl ether (ODA) in acetonitrile medium without any added surfactant. The active microspheres were characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and differential scanning calorimetry (DSC). The results revealed that the active microspheres had clean surfaces and they were in the size of micrometer range, varying from 0.5 to 2.5 mu m. The accessibility of the surface amino groups to further functionalization was confirmed by the reaction of these groups with benzoxy chloride. Interestingly, the content of amino groups can be easily tailored through changing the molar ratio of HCCP to ODA. The effects of the concentration of HCCP and the monomer ratios on the morphology were also discussed.
[Show abstract][Hide abstract] ABSTRACT: Novel polyphosphazene nanotubes with active hydroxyl groups were fabricated via an in situ template approach under ultrasonic irradiation. SEM and TEM results indicated that the nanotubes were uniform with length of several micrometers, inner diameter of ca. 20nm and outer diameter of 60–80nm. FTIR spectra revealed that the content of the hydroxyl groups on the nanotube surface was dependent on the feed ratio of hexachlorocyclotriphosphazene (HCCP) to 4,4′-sulfonyldiphenol. The successful esterification of polymer nanotubes with benzoxy chloride demonstrated the high reactivity of the hydroxyl groups. The method employed here might provide a simple and effective way to prepare functional nanotubes used for biological applications.
[Show abstract][Hide abstract] ABSTRACT: Cyclotriphosphazene-containing polymer nanofibers with uniform diameters, high aspect ratios, and high specific surface area have been synthesized rapidly at high yields under ultrasonic irradiation via a self-directing template approach. During the polymerization, triethylamine (TEA) as an acid acceptor absorbed a byproduct hydrogen chloride (HCl) to afford triethylamine hydrochloride (TEACl), acting as structure-directing template and guiding the formation of nanofibrous structures. The mechanism was confirmed by means of SEM, TEM, FTIR, XRD, TG, and N2 adsorption method. The molecular structure of as-synthesized polymer nanofibers was characterized by solid state NMR and elemental analysis.
European Polymer Journal 11/2008; 44(11):3466-3472. DOI:10.1016/j.eurpolymj.2008.08.026 · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Silver/organic−inorganic hybrid poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) coaxial nanocables were prepared by a facile method that involves two steps: the synthesis of silver nanowires through a soft, self-seeding, polyol process followed by adhesion of the PZS nanoparticles on the surface of silver nanowires to generate a cablelike nanostructure. Both Fourier transform infrared spectroscopy and elemental analysis were used to identify the highly cross-linked structures of PZS layers. Scanning electron microscopy and transmission electron microscopy results indicated that the nanocables had a core ca. 80 nm in diameter and a surrounding sheath with controllable thickness. Thermogravimetric analysis showed that the silver/PZS nanocables were stable up to 440 °C under air atmosphere. This approach could be extended to other metal nanocables wrapped with highly cross-linked organic−inorganic hybrid polyphosphazenes.
The Journal of Physical Chemistry C 10/2008; 112(43). DOI:10.1021/jp8063855 · 4.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Novel polyphosphazene nanotubes with closed ends were prepared by polycondensation of HCCP and BPS via an in situ template approach at room temperature. The nanotubes were characterized by FT-IR and NMR spectroscopy and elemental analysis. Their cross-linked structures were confirmed. SEM and TEM indicated that they resemble capsicum, with a length of 2-6 mu m, and the outer diameters of the two ends were about 200-500 and 100 nm. The majority of nanotubes had inner diameters of about 30-50 nm. The tube ends were closed. TGA analysis showed that their decomposition started at 468 degrees C. A formation mechanism of the capsicum-like nanotubes is proposed.
[Show abstract][Hide abstract] ABSTRACT: Multi-morphology control between monodisperse microspheres and uniform nanofibers was successfully achieved by adjusting the ratio of solvent composition. Through the condensation polymerization between hexachlorocyclotriphosphazene and 4,4′-sulfonyldiphenol, the corresponding hybrid inorganic–organic materials appeared. The morphology of both microspheres and nanofibers contained excellent size and shape: the monodisperse microspheres with 0.7–0.9 μm in diameter and the uniform nanofibers with 60 nm in outer diameter. We applied the concept of three-dimensional Hansen solubility parameters for the initial explanation. The activity of the primary colloid particles and the solubility of triethylamine–hydrogen chloride crystal were considered as two factors for the mechanism explanation. This interesting research shows that the nano- and micro-materials with high crosslinked molecule structure and prepared by condensation polymerization can also achieve the morphology transition. It fills the blank in nano-morphology transition research and will provide great information for the research about the control of different morphology preparations based on polymer nanomaterials.
Materials Science and Engineering B 09/2008; 153(1-3):62-65. DOI:10.1016/j.mseb.2008.10.027 · 2.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Polyphosphazene nanotubes with about 20 nm in inner diameter and 100–200 nm in outer diameter were fabricated easily and then carbonized at 800 °C in a nitrogen atmosphere. Scanning electron microscopy and transmission electron microscope results showed that the bulk morphology of polyphosphazene nanotubes was retained after carbonization. The carbon content of the carbonized samples reached 93.28%. X-ray diffraction and Raman spectrum showed that the carbonized samples had low graphitization state. The present method can be used for a mass production of carbon nanotubes.
[Show abstract][Hide abstract] ABSTRACT: Three new anthranilic acid derivatives, N-heneicosanoylanthranilic acid (1b), N-tricosanoylanthranilic acid (1d), N-tetracosanoylanthranilic acid (1e), and two known N-arachidylanthranilic acid (1a) and N-docosanoylanthranilic acid (1c) were isolated from the aerial parts of Inula japonica Thunb. Their structures were established by spectroscopic and chemical methods.
Chinese Chemical Letters 05/2008; 19(5):556-558. DOI:10.1016/j.cclet.2008.03.026 · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Based on an in situ template method, branched phosphazene-containing nanotubes were synthesized via a controlled two-step adding technique of acid acceptors. Structural and morphological characterizations of the as-synthesized products were performed by SEM, TEM, EDX and FTIR. The results showed that the branched nanotubes were had inner and outer diameters of 8 and 50–150 nm, respectively. In addition, a formation mechanism for the nanostructures was proposed.
[Show abstract][Hide abstract] ABSTRACT: Monodisperse cyclotriphosphazene containing microspheres with active hydroxyl groups were prepared via a simple, economic and environmentally friendly route, one-step precipitation polymerization. The resulting polymer particles had spherical shapes and smooth surfaces with narrow particle dispersal. From the FTIR spectra and the result of elemental analysis, it was obvious that the content of the hydroxyl groups on the surface was depended upon the feed ratio. The successful esterification with benzoxy chloride demonstrated the high active of the hydroxyl groups on the poly (cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) microspheres' surface. This interesting approach might open a novel, simple and economic route to preparing the functional microspheres.