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51.
Stella Makedonopoulou John Papaioannou Ioulia Argyroglou Irene M. Mavridis 《Journal of inclusion phenomena and macrocyclic chemistry》2000,36(2):191-215
The structures of the inclusion complexes of beta cyclodextrin with the aliphatic mono-acids tridecanoic acid (1) and (Z)-tetradec-7-enoic acid (2) have been determined at room temperature. Both compounds crystallise in P1, a = 15.654(6) Å, b = 15.650(6) Å, c = 15.937(6) Å, = 101.58(1)°, = 101.59(1)°, = 103.58(1)°, Z = 1, for 1 and a = 15.6259(9) Å, b = 15.623(1) Å, c = 15.935(1) Å, = 101.547(2)°, = 101.555(2)°, = 103.642(2)°, Z = 1, for 2. One molecule of the monoacids threads through two cyclodextrin macrocycles arranged in dimers thus forming [3]pseudorotaxanes. The host dimers are aligned along a channel in order to create a hydrophobic environment for the terminal methyl group of the guest and isolate it from the aqueous environment that surrounds the cyclodextrin dimeric units. The guests exhibit disorder over two orientations resulting in hydrogen bonding between the carboxyl groups of adjacent guest molecules along the channel and formation of carboxylic dimers. This crystal packing differs from that of -CD complexes of homologous dicarboxylic acids. 相似文献
52.
Christos Vassileiou Stefania Kalantzi Eleanna Vachlioti Constantinos M. Athanassopoulos Christos Koutsakis Zoi Piperigkou Nikos Karamanos Theodora Stivarou Peggy Lymberi Konstantinos Avgoustakis Dionissios Papaioannou 《Molecules (Basel, Switzerland)》2022,27(2)
Polyamine toxins (PATs) are conjugates of polyamines (PAs) with lipophilic carboxylic acids, which have been recently shown to present antiproliferative activity. Ten analogs of the spider PATs Agel 416, HO-416b, and JSTX-3 and the wasp PAT PhTX-433 were synthesized with changes in the lipophilic head group and/or the PA chain, and their antiproliferative activity was evaluated on MCF-7 and MDA-MB-231 breast cancer cells, using Agel 416 and HO-416b as reference compounds. All five analogs of PhTX-433 were of very low activity on both cell lines, whereas the two analogs of JSTX-3 were highly active only on the MCF-7 cell line with IC50 values of 2.63–2.81 μΜ. Of the remaining three Agel 416 or HO-416b analogs, only the one with the spermidine chain was highly active on both cells with IC50 values of 3.15–12.6 μM. The two most potent compounds in this series, Agel 416 and HO-416b, with IC50 values of 0.09–3.98 μΜ for both cell lines, were found to have a very weak cytotoxic effect on the MCF-12A normal breast cells. The present study points out that the structure of both the head group and the PA chain determine the strength of the antiproliferative activity of PATs and their selectivity towards different cells. 相似文献
53.
Virginia D. Dimaki Konstantina Zeliou Fotini Nakka Michaela Stavreli Ioannis Bakratsas Ligeri Papaioannou Gregoris Iatrou Fotini N. Lamari 《Molecules (Basel, Switzerland)》2022,27(21)
Sideritis clandestina (Bory & Chaub.) Hayek subsp. peloponnesiaca (Boiss. & Heldr.) Baden (SCP) is endemic to the mountains of the Northern Peloponnese (Greece). This and other Sideritis taxa, collectively known as mountain tea, are widely ingested as beverages for refreshment or medicinal purposes. We describe a methodology for the characterization of SCP. Four iridoid glycosides (monomelittoside, melittoside, ajugoside, and 7-O-acetyl-8-epiloganic acid), two phenolic acid glycosides (vanillic and salicylic acid glycosides), and three caffeoyl ester glycosides (chlorogenic acid, verbascoside, and isoverbascoside) were isolated from SCP for the first time. We used ultrasound-assisted extraction of 3 g of plant material to produce petroleum ether and aqueous extracts, which we then analyzed using GC/MS and LC/MS. This was applied to eight samples from four different taxa. In total, 70 volatile and 27 polar metabolites were determined. The S. clandestina samples had a lower phenolic content and weaker antioxidant properties than S. raeseri and S. scardica. However, S. clandestina ssp. clandestina seemed to be the most aromatic taxon, with almost double the number of volatiles as the others. Τhis study could contribute to authentication and chemotaxonomic studies of Sideritis taxa. 相似文献
54.
The essential oils from stems, leaves, inflorescences, and both unripe and ripe infructescences of Smyrnium olusatrum L. (Umbelliferae) collected in Greece were obtained by hydrodistillation and analyzed by GC-FID and GC-MS. Fifty-eight components were identified. Among the samples analyzed, the differences observed were mainly quantitative. All oils were characterized by the abundance of sesquiterpenes. The major components of the stem and leaf oils were furanoeremophil-1-one (54.3% and 28.7%, respectively) and curzerene (18.8%, 29.0%). The main constituents of the inflorescence oil were curzerene (38.1%), germacrone (20.2%) and furanoeremophil-1-one (20.0%), while those of the unripe and ripe infructescence oils were 1beta-acetoxy-furanoeudesm-4(15)-ene (22.1%, 30.8%) and curzerene (29.7%, 17.4%). 相似文献
55.
George E. Magoulas Thomas Garnelis Constantinos M. Athanassopoulos Dionissios Papaioannou George Mattheolabakis Konstantinos Avgoustakis Dimitra Hadjipavlou-Litina 《Tetrahedron》2012,68(35):7041-7049
(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C60, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine. 相似文献
56.
This paper presents a literature review of the cell formation (CF) problem concentrating on formulations proposed in the last decade. It refers to a number of solution approaches that have been employed for CF such as mathematical programming, heuristic and metaheuristic methodologies and artificial intelligence strategies. A comparison and evaluation of all methodologies is attempted and some shortcomings are highlighted. Finally, suggestions for future research are proposed useful for CF researchers. 相似文献
57.
58.
Paul D. W. Bottomley Thomas Gouder Frank Huber Dimitrios Papaioannou Didier Pellottiero 《Mikrochimica acta》2004,145(1-4):3-12
Samples of the thoria thermal shroud from the plenum and a deposition coupon from a filter cartridge of the FPT4 test of the Phebus PF project were examined using electron-optical analysis and by photoemission spectroscopy (XPS). The aim was to determine the nature of the fission product deposits formed under conditions of severe nuclear accidents. The plenum had considerable deposits containing Zr, Mo, Ba, Cs, and locally U was found by energy dispersive analysis. The XPS analysis showed that the deposits are mostly in oxidic form, but no U was found in the deposit, although chemical analysis showed considerable amounts present. A possible explanation is that there is layering of the deposit and that U is not released in the early stages. The coupon had very sparse deposits with only occasional U and Re particles; however large, pure Cs particles were observed on the surface that may have come from the filter deposits upstream. Thus an estimate of the deposition behaviour of fission product and fuel dispersed under extreme nuclear accident conditions is built up. 相似文献
59.
Scanning electron microscopy study on nanoemulsions and solid lipid nanoparticles containing high amounts of ceramides 总被引:1,自引:0,他引:1
Hatziantoniou S Deli G Nikas Y Demetzos C Papaioannou GT 《Micron (Oxford, England : 1993)》2007,38(8):819-823
Ceramides are the most important intercellular lipids of the stratum corneum, regulating the barrier function of the skin and participating as second signal messenger in stress-induced apoptosis. The high lipophilicity of ceramides presents a pharmacological problem. In order to overcome this problem two lipophilic delivery systems were used for the incorporation of the ceramides: (1) nanoemulsions (NE) and (2) solid lipid nanoparticles (SLN). The influence of the incorporation of ceramides on the particle shape, size and Polydispersity Index was investigated by photon correlation spectroscopy (PCS) and scanning electron microscopy (SEM). The results showed that NE can incorporate larger amounts of ceramides than SLN (up to 23.2% and 5% of lipid matrix, respectively) without any significant alteration on the morphology of the dispersed particles. The incorporation of higher amounts of ceramides into SLN, leads to anisometric platelet-like formations that are known to be caused by the transition of triglycerides from - to β-mesomorph. The results of this study can be useful for the design of appropriate delivery systems and for further pharmacological evaluations. 相似文献
60.
This work is concerned with the initial‐boundary value problem for the Boussinesq equation. By employing the unified transform method of Fokas, novel solution formulae for the linearized “good” Boussinesq equation on the half‐line with various initial and boundary conditions are obtained. Moreover, these solution formulae are numerically illustrated in the case of concrete data. Finally, Boussinesq's original physical derivation of the so‐called “bad” Boussinesq equation is provided. 相似文献