Cytotoxic,Apoptosis-Inducing Activities,and Molecular Docking of a New Sterol from Bamboo Shoot Skin Phyllostachys heterocycla var. pubescens

Phytochemical screening of nonpolar fractions from the methanol extract of the Bamboo shoot skin Phyllostachys heterocycla var. pubescens resulted in the isolation of a new sterol-glucoside-fatty acid derivative (6’-O-octadeca-8″,11″-dienoyl)-sitosterol-3-O-β-d-glucoside (1), together with six known compounds. The chemical structures of the pure isolated compounds were deduced based on different spectral data. The isolated compounds were assessed to determine their cytotoxic activity, and the results were confirmed by determining their apoptotic activity. Compound 1 was more cytotoxic against the MCF-7 cells (IC₅₀ = 25.8 µM) compared to Fluorouracil (5-FU) (26.98 µM), and it significantly stimulated apoptotic breast cancer cell death with 32.6-fold (16.63% compared to 0.51 for the control) at pre-G1 and G2/M-phase cell cycle arrest and blocked the progression of MCF-7 cells. Additionally, RT-PCR results further confirmed the apoptotic activity of compound 1 by the upregulation of proapoptotic genes (P53; Bax; and caspases 3, 8, and 9) and downregulation of the antiapoptotic genes (BCL2). Finally, the identified compounds, especially 1, were found to have high binding affinity towards both tyrosine-specific protein kinase (TPK) and vascular endothelial growth factor receptor (VEGFR-2) through the molecular docking studies that highlight its mode of action.     

Characterization of Ce@C82 and its anion

Ce@C(82) is isolated by high-performance liquid chromatography (HPLC) and the cage symmetry is determined as C(2)(v)() by measuring the (13)C NMR spectra of its anion. The (13)C NMR peaks of [Ce@C(82)](-) show temperature-dependent shifts ascribed to the f electron remaining on the Ce atom. Both Ce@C(82) and [Ce@C(82)](-) are silent in electron spin resonance spectroscopy (ESR) because of the highly anisotropic g matrix as well as of the fast relaxation process originating from the orbital angular momentum of the f electron. This is the complementary relationship to the observation of the paramagnetic shift in (13)C NMR. [Ce@C(82)](-) has lower stability in air than [La@C(82)](-).     

AFM observation of cation complexation of dibenzocrown ethers adsorbed on highly oriented pyrolytic graphite

The cation complexation behavior of dibenzocrown ethers adsorbed on highly oriented pyrolytic graphite substrates was investigated by means of atomic force microscopy using probe tips modified chemically with ammonium ion by silane coupling. The specific adhesion force based on the intermolecular force between dibenzocrown ether and ammonium ion was observed via force curve measurements in ethanol at the interface between the substrate and tip. The observed specific force decreased in the presence of the alkali metal ion in solution, indicating that the cation in solution interferes with the complexation of the crown ethers adsorbed on the substrate with the ammonium ion immobilized on the tip. The blocking effect of metal ions in solution on the observed force depended on the sizes of both the blocking cation and crown ether ring, suggesting that the surface-adsorbed dibenzocrown ethers possess a selective cation-complexing ability similar to that in their bulk state and that the adhesion force measurements using cation-modified tips allow evaluation of the cation-complexing ability of crown ethers under cation-competitive conditions.     

Synthesis of allenes from allylic alcohol derivatives bearing a bromine atom using a palladium(0)/diethylzinc system

A general and efficient synthesis of allenes using a palladium(0)/diethylzinc system is described. Treatment of mesylates or trichloroacetates of (E)- or (Z)-2-bromoalk-2-en-1-ols with diethylzinc in the presence of a catalytic amount of palladium(0) affords allenes bearing an aminoalkyl, alkyl, or aryl substituent(s) in good to high yields. No transfer of chirality from the stereogenic center carrying the mesyloxy group to the allene was observed.     

Ground state spectroscopic constants of isothiocyanic acid,HNCS, from its microwave and millimeter wave spectra combined with far infrared data

The microwave and millimeter wave spectra of isothiocyanic acid, HNCS, in the ground vibrational state have been investigated in the frequency region 8–300 GHz. The a-type R-branch transitions have been assigned up to J = 25 and K_a = 4, and the a-type ^qQ₁ branch transitions up to J = 45. No b-type transitions could be identified in the frequency region covered. The far infrared data reported by Krakow, Lord, and Neely [J. Mol. Spectrosc., 27, 148 (1968)] were combined with our millimeter wave data in order to determine reliable spectroscopic constants. The rotational Hamiltonian, Watson's formalism with S reduction, has been extended empirically to higher order to facilitate the fitting of the large centrifugal distortion effects. The obtained constants are:

$\text{A = 1357.3 GHz; B = 5883.4627 MHz; C = 5845.6113 MHz; D}{}_{\mathrm{J}}\text{= 1.19393 kHz; D}{}_{\mathrm{JK}}\text{= ?1025.37 kHz; D}{}_{\mathrm{K}}\text{= 51.57 GHz; d}{}_1\text{= ?13.781 Hz; d}{}_2\text{= ?4.59 Hz.}$

The ¹⁴N quadrupole coupling constant has also been determined: χ_aa = 1.114 MHz.     

Laser Stark spectroscopy of formaldehyde-d2: The Coriolis coupled ν4 and ν6 fundamentals

Using CO₂ and N₂O lasers, we have measured and assigned nineteen ν₄ and nine ν₆ rotation-vibration resonances of the type ΔM = 0 and M = J. These transitions were combined with the zero-field pure rotational spectra in order to determine the two fundamental vibrational frequencies, the rotational constants of both excited states, the Coriolis coupling constant, and the dipole moments of each of the three states. The ground-state rotational constants and centrifugal distortion constants were taken from a microwave study and the centrifugal distortion constants of the excited states were assumed equal to those of the ground state. The following results were obtained (standard deviations in parentheses):

     

907.

Anisotropy in second-harmonic generation from reconstructed surfaces of GaAs     

Yamada C  Kimura T 《Physical review letters》1993,70(15):2344-2347

     

908.

Depression of the apparent chiral recognition ability obtained in the host-guest complexation systems by electrospray and nano-electrospray ionization mass spectrometry   总被引：2，自引：0，他引：2  

Sawada M  Takai Y  Yamada H  Yoshikawa M  Arakawa R  Tabuchi H  Takada M  Tanaka J  Shizuma M  Hirose K  Fukuda K  Tobe Y 《European journal of mass spectrometry (Chichester, England)》2004,10(1):27-37

Chiral recognition in the host-guest complexation systems of chiral crown ether hosts and amino ester guests was thoroughly examined using the electrospray ionization (ESI) mass spectrometry/enantiomer labeled (EL)-guest method. In this method, the mass spectra of a mixture of three components in a solution, a chiral host (H), an equal amount of an (S)-enantiomer guest labeled with deuterium atoms (G(S-dn)(+)) and an unlabeled (R)-enantiomer guest (G(R)+), were measured and the relative peak intensity value [I(H + G(R))(+) / I(H + G(S-dn))(+) = IRIS] of the host-guest complex ions, observed with an excess guest concentration, was taken to provide the chiral recognition ability of the host. In our earlier report (1996), we demonstrated that the apparent chiral recognition abilities using a mass spectrometer with a homemade ESI interface were depressed by about one tenth compared with the corresponding abilities obtained by fast-atom bombardment (FAB) MS. In the present study, the enantioselective complexation behaviors of various combinations of chiral crown hosts with chiral guests were further investigated in detail mainly using a modern commercial ESI/ion trap (IT) mass spectrometer. Consequently, it was found that the apparent IRIS values from the ESI-MS/EL-guest method changed significantly, depending upon the instrument used, and in particular, upon the ESI interfaces. Moreover, under the specific measuring conditions in ESI-IT-MS, the degrees of depression of the apparent chiral recognition abilities are roughly grouped into three classes, depending upon the number (or probably the type) of the hydrophobic substituents of the hosts. Representing the degrees by the slopes when plotting the apparent IRIS values in ESI-MS versus those in FAB-MS, the slopes for the three classes are (1) 1.0, (2) 0.7 and (3) 0.3; the higher the hydrophobicity of the hosts (and then, the host-guest complex ions), the lower the slope (the apparent enantioselectivity). Strengthening the degree of depression may be caused by an increase in the local concentration of the host close to the surface of the droplets produced during the electrospary ionization process. The chiral recognition ability (K(R )/ K(S)) in an equilibrated solution agrees quite well with the IRIS value in FAB-MS rather than that in ESI-MS.     

909.

用动态粘弹函数关系表征PMMA/α-MSAN共混物的相分离   总被引：2，自引：0，他引：2  

郑强  荒木修  升田利史郎 《高等学校化学学报》1998,19(8):1339-1342

测定了聚甲基丙烯酸甲酯／聚（α－甲基苯乙烯丙烯腈）共混物熔体的动态粘弹性．考察动态储能模量Ｇ′与动态损耗模量Ｇ″的关系，发现在终端区域两种聚合物的ｌｇＧ′～ｌｇＧ″关系曲线与温度无关，其外推直线斜率接近２；而其共混物的斜率明显小于２，并随组成变化呈现温度依赖性，由此得到的“临界温度”可用于表征这种具有ＬＣＳＴ行为的共混物的相容性．     

910.

The chemistry of indoles. CIII. Simple syntheses of serotonin, N-methylserotonin, bufotenine, 5-methoxy-N-methyltryptamine, bufobutanoic acid, N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine, and lespedamine based on 1-hydroxyindole chemistry     

Somei M  Yamada F  Kurauchi T  Nagahama Y  Hasegawa M  Yamada K  Teranishi S  Sato H  Kaneko C 《Chemical & pharmaceutical bulletin》2001,49(1):87-96

Application of regioselective nucleophilic substitution reactions of 1-hydroxytryptamines to novel and simple syntheses of serotonin (1a), N-methylserotonin (1b), bufotenine (1c), 5-methoxy-N-methyltryptamine (2a), bufobutanoic acid (3a), N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine (4), and lespedamine (5) are described. Effective syntheses of 5-benzyloxytryptamine and 1-methoxy-2-oxindoles are also reported.     

[首页] « 上一页 [86] [87] [88] [89] [90] 91 [92] [93] [94] [95] [96] 下一页 » 末  页»

		$\text{ν}{}_4$		$\text{ν}{}_6$
$\text{ν}{}_0$		938.0345 (6)		989.2519 (18)		(cm?1)
$\text{A}$		139 579 (150)		143 323 (150)		(MHz)
$\text{B}$		31 873.6 (5)		32 379.5 (7)		(MHz)
$\text{C}$		26 242.9 (6)		25 994.4 (8)		(MHz)
$\text{ξ}{}_{64}{}^{\mathrm{(a)}}$			136 178 (770)			(MHz)
μ		2.319 (10)		2.347 (4)		(D)
μ(ground state)			2.3464 (8)			(D)

Depression of the apparent chiral recognition ability obtained in the host-guest complexation systems by electrospray and nano-electrospray ionization mass spectrometry

Chiral recognition in the host-guest complexation systems of chiral crown ether hosts and amino ester guests was thoroughly examined using the electrospray ionization (ESI) mass spectrometry/enantiomer labeled (EL)-guest method. In this method, the mass spectra of a mixture of three components in a solution, a chiral host (H), an equal amount of an (S)-enantiomer guest labeled with deuterium atoms (G(S-dn)(+)) and an unlabeled (R)-enantiomer guest (G(R)+), were measured and the relative peak intensity value [I(H + G(R))(+) / I(H + G(S-dn))(+) = IRIS] of the host-guest complex ions, observed with an excess guest concentration, was taken to provide the chiral recognition ability of the host. In our earlier report (1996), we demonstrated that the apparent chiral recognition abilities using a mass spectrometer with a homemade ESI interface were depressed by about one tenth compared with the corresponding abilities obtained by fast-atom bombardment (FAB) MS. In the present study, the enantioselective complexation behaviors of various combinations of chiral crown hosts with chiral guests were further investigated in detail mainly using a modern commercial ESI/ion trap (IT) mass spectrometer. Consequently, it was found that the apparent IRIS values from the ESI-MS/EL-guest method changed significantly, depending upon the instrument used, and in particular, upon the ESI interfaces. Moreover, under the specific measuring conditions in ESI-IT-MS, the degrees of depression of the apparent chiral recognition abilities are roughly grouped into three classes, depending upon the number (or probably the type) of the hydrophobic substituents of the hosts. Representing the degrees by the slopes when plotting the apparent IRIS values in ESI-MS versus those in FAB-MS, the slopes for the three classes are (1) 1.0, (2) 0.7 and (3) 0.3; the higher the hydrophobicity of the hosts (and then, the host-guest complex ions), the lower the slope (the apparent enantioselectivity). Strengthening the degree of depression may be caused by an increase in the local concentration of the host close to the surface of the droplets produced during the electrospary ionization process. The chiral recognition ability (K(R )/ K(S)) in an equilibrated solution agrees quite well with the IRIS value in FAB-MS rather than that in ESI-MS.     

用动态粘弹函数关系表征PMMA/α-MSAN共混物的相分离

测定了聚甲基丙烯酸甲酯／聚（α－甲基苯乙烯丙烯腈）共混物熔体的动态粘弹性．考察动态储能模量Ｇ′与动态损耗模量Ｇ″的关系，发现在终端区域两种聚合物的ｌｇＧ′～ｌｇＧ″关系曲线与温度无关，其外推直线斜率接近２；而其共混物的斜率明显小于２，并随组成变化呈现温度依赖性，由此得到的“临界温度”可用于表征这种具有ＬＣＳＴ行为的共混物的相容性．     

The chemistry of indoles. CIII. Simple syntheses of serotonin, N-methylserotonin, bufotenine, 5-methoxy-N-methyltryptamine, bufobutanoic acid, N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine, and lespedamine based on 1-hydroxyindole chemistry

Application of regioselective nucleophilic substitution reactions of 1-hydroxytryptamines to novel and simple syntheses of serotonin (1a), N-methylserotonin (1b), bufotenine (1c), 5-methoxy-N-methyltryptamine (2a), bufobutanoic acid (3a), N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine (4), and lespedamine (5) are described. Effective syntheses of 5-benzyloxytryptamine and 1-methoxy-2-oxindoles are also reported.