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1.
Carmine Coluccini Yoke Mooi Ng Yves Ira A. Reyes Hsin-Yi Tiffany Chen Yit Lung Khung 《Molecules (Basel, Switzerland)》2020,25(22)
In this paper, a modified Cyclotriveratrylene was synthesized and linked to a branched Polyethylenimine, and this unique polymeric material was subsequently examined as a potential supramolecular carrier for Doxorubicin. Spectroscopic analysis in different solvents had shown that Doxorubicin was coordinated within the hollow-shaped unit of the armed Cyclotriveratrylene, and the nature of the host–guest complex revealed intrinsic Van der Waals interactions and hydrogen bonding between the host and guest. The strongest interaction was detected in water because of the hydrophobic effect shared between the aromatic groups of the Doxorubicin and Cyclotriveratrylene unit. Density functional theory calculations had also confirmed that in the most stable coordination of Doxorubicin with the cross-linked polymer, the aromatic rings of the Doxorubicin were localized toward the Cyclotriveratrylene core, while its aliphatic chains aligned closer with amino groups, thus forming a compact supramolecular assembly that may confer a shielding effect on Doxorubicin. These observations had emphasized the importance of supramolecular considerations when designing a novel drug delivery platform. 相似文献
2.
Studies involving metal enhancement effects have gained popularity, and enhancement of fluorescence due to the close proximity of a dye molecule to a metal nanoparticle is well documented. Although enhancement of singlet oxygen production by metal has been reported, studies are relatively scarce and so far only stationary silver island films have been proven to be adequate to do so. Herein, we describe the synthesis and characterization of core–shell nanoparticles on which a photosensitizer acting as source of singlet oxygen has been covalently attached to the nanoparticle surface. As a proof of concept, silver nanoparticles with a diameter around 68 nm were chosen as the metallic core, and were coated by a silica shell of about 22 nm in thickness. The silica shell plays a dual role as a spacer and a medium onto which the photosensitizer, rose bengal (RB), has been covalently attached. These novel core–shell nanoparticles allow for the amplification of singlet oxygen production by 3.8 times, which is similar to the amplification found for RB in proximity of silver island films. 相似文献
3.
SS Teh G Cheng Lian Ee SH Mah YM Lim M Rahmani 《Molecules (Basel, Switzerland)》2012,17(9):10791-10800
An investigation on biologically active secondary metabolites from the stem bark of Mesua beccariana was carried out. A new cyclodione, mesuadione (1), along with several known constituents which are beccamarin (2), 2,5-dihydroxy-1,3,4-trimethoxy anthraquinone (3), 4-methoxy-1,3,5-trihydroxyanthraquinone (4), betulinic acid (5) and stigmasterol (6) were obtained from this ongoing research. Structures of these compounds were elucidated by extensive spectroscopic methods, including 1D and 2D-NMR, GC-MS, IR and UV techniques. Preliminary tests of the in vitro cytotoxic activities of all the isolated metabolites against a panel of human cancer cell lines Raji (lymphoma), SNU-1 (gastric carcinoma), K562 (erythroleukemia cells), LS-174T (colorectal adenocarcinoma), HeLa (cervical cells), SK-MEL-28 (malignant melanoma cells), NCI-H23 (lung adenocarcinoma), IMR-32 (neuroblastoma) and Hep-G2 (hepatocellular liver carcinoma) were carried out using an MTT assay. Mesuadione (1), beccamarin (2), betulinic acid (5) and stigmasterol (6) displayed strong inhibition of Raji cell proliferation, while the proliferation rate of SK-MEL-28 and HeLa were strongly inhibited by stigmasterol (6) and beccamarin (2), indicating these secondary metabolites could be anti-cancer lead compounds in drug discovery. 相似文献
4.
Phytochemical studies of the leaves and rhizomes of Paraboea pa niculata (Gesneriaceae) are reported for the first time. Three phenylethanoid glycosides were isolated and characterized as 3,4-dihydroxyphenethyl-(3"-O-beta-D-apiofuranosyl)-beta-D-glucopyranoside, calceoralarioside E, and acteoside. These isolates exhibited weak cytotoxic activity against the K-562 cell line with a 50% of cell killing rate of 40.18 microM, 27.05 microM, and 27.24 microM, respectively. In the DPPH free radical scavenging assay, their IC50 values were determined as 75.89 microM, 25.00 microM, and 26.04 microM, respectively. 相似文献
5.
A.F. Maarten Altelaar Ioana M. Taban Liam A. McDonnell Peter D.E.M. Verhaert Robert P.J. de Lange Roger A.H. Adan Wolter J. Mooi Ron M.A. Heeren Sander R. Piersma 《International journal of mass spectrometry》2007,260(2-3):203
Matrix assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) has been used to determine peptide distributions directly from rat, mouse and human pituitary tissue sections. Since these organs are small (102–103 μm) the spatial resolution of IMS is a key issue in molecular imaging of pituitary tissue sections. Here we show that high-resolution IMS allows localization of neuropeptide distributions within different cell clusters of a single organ of a pituitary tissue section. The sample preparation protocol does not result in analyte redistribution and is therefore applicable to IMS experiments at cellular length scales. The stigmatic imaging mass spectrometer used in this study produces selected-ion-count images with pixel sizes of 500 nm and a resolving power of 4 μm, yielding superior spatial detail compared to images obtained in microprobe imaging experiments. Furthermore, we show that with imaging mass spectrometry a distinction can be made between different mammalian tissue sections based on differences in the amino acid sequence of neuropeptides with the same function. This example demonstrates the power of IMS for label-free molecular imaging at relevant biological length scales. 相似文献
6.
A new furanodihydrobenzoxanthone, artomandin (1), together with three other flavonoid derivatives, artoindonesianin C, artonol B, and artochamin A, as well as β-sitosterol were isolated from the stem bark of Artocarpus kemando. The structures of these compounds were determined on the basis of spectral evidence. All of these compounds displayed inhibition effects to a very susceptible degree in cancer cell line tests. Compound 1 also exhibited significant antioxidant capacity in the free radical 1,1-diphenyl-2-picrylhydrazyl tests. 相似文献
7.
VON SZENTPáLY László 《物理化学学报》2018,34(6):675-682
The addition of electrons to form gas-phase multiply charged anions (MCAs) normally requires sophisticated experiments or calculations.In this work, the factors stabilizing the MCAs, the maximum electron uptake of gas-phase molecules, X, and the electronic stability of MCAs XQ-, are discussed. The drawbacks encountered when applying computational and/or conceptual density functional theory (DFT) to MCAs are highlighted. We develop and test a different model based on the valence-state concept. As in DFT, the electronic energy, E(N, vex), is a continuous function of the average electron number, N, and the external potential, vex, of the nuclei. The valence-state-parabola is a second-order polynomial that allows extending E(N, vex) to dianions and higher MCAs. The model expresses the maximum electron acceptance, Qmax, and the higher electron affinities, AQ, as simple functions of the first electron affinity, A1, and the ionization energy, I, of the "ancestor" system. Thus, the maximum electron acceptance is Qmax, calc = 1 + 12A1/7(I -A1). The ground-state parabola model of the conceptual DFT yields approximately half of this value, and it is termed Qmax, GS = ${}^{1}\!\!\diagup\!\!{}_{2}\; $ + A1/(I -A1). A large variety of molecules are evaluated including fullerenes, metal clusters, super-pnictogens, super-halogens (OF3), super-alkali species (OLi3), and neutral or charged transition-metal complexes, ABmLn0/+/-. The calculated second electron affinity A2, calc = A1-(7/12)(I -A1) is linearly correlated to the literature references A2, lit with a correlation coefficient R = 0.998. A2 or A3 values are predicted for further 24 species. The appearance sizes, nap3-, of triply charged anionic clusters and fullerenes are calculated in agreement with the literature. 相似文献
8.
9.
Jumiah Hassan Farm Mooi Yen Mansor Hashim Zulkifly Abbas Zaidan Abdul Wahab W. Mohd. Daud W. Yusoff Azmi Zakaria 《Ionics》2007,13(4):219-222
NiFe2O4 prepared via the sol–gel technique were pre-sintered at 900 °C and synthesized at different sintering temperatures from 1,000 °C
to 1,200 °C at 100 °C intervals. The samples were characterized for microwave dielectric properties. These samples were measured
using Agilent Impedance/Material Analyzer at frequencies 1 MHz to 1.8 GHz. Results showed a decrease in the dielectric constant
and loss factor with frequency except at the turning point, around 150 MHz, where the loss factor showed a gradual increase.
However, both the dielectric constant and loss factor increase with increasing sintering temperature. The grain size and density
also increased with increasing sintering temperature, but the porosity and grain boundary density showed a decrease.
This paper was presented at the International Conference on Solid State Science and Technology 2006, Kuala Terengganu, Malaysia,
Sept. 4–6, 2006. 相似文献
10.
Bo-Long Poh Yoke Mooi Chow 《Journal of inclusion phenomena and macrocyclic chemistry》1992,14(2):85-90
The association constants of 1 : 1 complexes formed in water between six aromatic hydrocarbons (o-,m-, andp-xylene, naphthalene, anthracene, and pyrene) and- and-cyclodextrin were determined by the transport method. The values are in good agreement with those determined by other methods. 相似文献