Read by QxMD icon Read


Bangrong Cai, Aimei Liao, Kyung-Ku Lee, Jae-Sam Ban, Hyun-Sam Yang, Young Jun Im, ChangJu Chun
A series of methotrexate-diosgenin conjugates was designed and synthesized to enhance the passive internalization of methotrexate (MTX) into transport-resistant cells. The inhibitory effects of these conjugates on dihydrofolate reductase (DHFR), and their anti-proliferation behaviors against a transport-resistant breast cancer cell line, MDA-MB-231, were investigated. All of the synthesized conjugates retained an ability to inhibit DHFR after the diosgenin substitution. The MTX conjugates were much more potent against methotrexate-resistant MDA-MB-231 cells than MTX...
October 19, 2016: Steroids
Limin Xiang, Yihai Wang, Xiaomin Yi, Xiangjiu He
Phytochemical investigations of the rhizome of Tupistra chinensis led to the isolation of ten new furostanol saponins along with fourteen known spirostanols. Their chemical structures were elucidated on the basis of spectroscopic and chemical methods, including IR, NMR, MS, and GC analyses. The antiproliferative effects against FaDu and Detroit 562 cell lines and inhibitory activities on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in a macrophage cell line RAW 264.7 were assayed for all the isolated compounds...
October 19, 2016: Steroids
Carlo Barnaba, Maria Teresa Rodríguez-Estrada, Giovanni Lercker, Hugo Sergio García, Ilce Gabriela Medina-Meza
In this work we studied the effect of polyunsaturated fatty acids (PUFAs) methyl esters on cholesterol photo-induced oxidation. The oxidative routes were modeled with a chemical reaction network (CRN), which represents the first application of CRN to the oxidative degradation of a food-related lipid matrix. Docosahexaenoic acid (DHA, T-I), eicosapentaenoic acid (EPA, T-II) and a mixture of both (T-III) were added to cholesterol using hematoporphyrin as sensitizer, and were exposed to a fluorescent lamp for 48h...
October 15, 2016: Steroids
Alexander J Frey, Qingqing Wang, Christine Busch, Daniel Feldman, Lisa Bottalico, Clementina A Mesaros, Ian A Blair, Anil Vachani, Nathaniel W Snyder
A multiplexed quantitative method for the analysis of three major unconjugated steroids in human serum by stable isotope dilution liquid chromatography-high resolution mass spectrometry (LC-HRMS) was developed and validated on a Q Exactive Plus hybrid quadrupole/Orbitrap mass spectrometer. This quantification utilized isotope dilution and Girard P derivatization on the keto-groups of testosterone (T), androstenedione (AD) and dehydroepiandrosterone (DHEA) to improve ionization efficiency using electrospray ionization...
October 13, 2016: Steroids
Zsolt Nagy, Alexa Marta, Henriett Butz, Istvan Liko, Karoly Racz, Attila Patocs
Peripheral clocks are set by different nervous, hormonal and metabolic stimuli, and regulate the circadian expression of several genes. We investigated whether a peripheral clock could be induced in the human adrenocortical cell line H295R and whether glucocorticoid receptor isoforms (GRα and GRß) are involved in this clock system. After synchronization of cells with serum shock, the rhythmic oscillation of clock genes PER1, PER2, REV-ERBα, and ARNTL was confirmed. In addition, H295R cells even without serum shock showed rhythmic expression of PER1, PER2, CRY1 and ARNTL...
October 7, 2016: Steroids
Ailed Arenas-González, Luis Antonio Mendez-Delgado, Penélope Merino-Montiel, José M Padrón, Sara Montiel-Smith, José Luis Vega-Báez, Socorro Meza-Reyes
The synthesis of several monomeric and dimeric steroidal [1,2,4]triazolo[1,5-a]pyrimidines (TPs) derived from steroids are described. These derivatives were prepared from α,β-unsaturated carbonyl compounds through a Claisen Schmidt condensation and rearrangement of the spiro moiety followed by a cycloaddition with 3-amino-1,2,4-triazole. The antiproliferative activity of compounds 7, 13-15 was tested against human cancer cells; several IG50 values were below 10μM.
October 6, 2016: Steroids
Yaroslav Faletrov, Anna Brzostek, Renata Plocinska, Jarosław Dziadek, Elena Rudaya, Irina Edimecheva, Vladimir Shkumatov
Fluorescent steroids BODIPY-cholesterol (BPCh) and 7-nitrobenzoxadiazole-4-amino-(NBD)-labeled 22-NBD-chelesterol (22NC) as well as synthesized 20-(NBD)-pregn-5-en-3β-ol (20NP) were found to undergo bioconversions by Mycobacterium tuberculosis H37Rv and M. smegmatis mc(2) 155. The major fluorescent products were determined to be 4-en-3-one derivatives of the compounds. Degradation of NBD fluorophore was also detected in the cases of 22NC and 20NP, but neither NBD degradation nor steroidal part modification were observed for the synthesized 3-(NBD)-cholestane...
October 5, 2016: Steroids
Luc Rocheblave, Marc Rolland de Ravel, Elodie Monniot, Jeremy Tavenard, Claude-Yves Cuilleron, Catherine Grenot, Sylvie Radix, Eva-Laure Matera, Charles Dumontet, Nadia Walchshofer
Deoxycholic acid derivatives were designed as P-glycoprotein (Pgp, ABCB1) inhibitors. Thus the synthesis and the biological activity of methyl deoxycholate derivatives 5-10 and their ether analogs 15-20 have been reported. The potency of these compounds to modulate Pgp-mediated MDR was evaluated through daunorubicin accumulation and potentiation of doxorubicin cytotoxicity in K562/R7 multidrug resistant cells overexpressing Pgp. In parallel, their intrinsic toxicity was appreciated on K562 sensitive cells. Methyl 12α-[(2R or 2S) tetrahydro-2H-pyran-2-yloxy]-3-oxo-5β-cholan-24-oate 9b has shown a good efficiency as a Pgp inhibitor and a low intrinsic toxicity...
September 30, 2016: Steroids
K S Marenin, Yu V Gatilov, A M Agafontsev, A V Tkachev
Reaction of nitrosochlorides of natural monoterpene hydrocarbons (+)-3-carene and (-)-α-pinene with L-amino acids and their methyl esters results in stereoselective formation of terpene-amino acids hybrids, which belong to the series of α-substituted amino oximes. The reaction with an excess of racemic DL-amino acids and their derivatives induces partial resolution of the amino acid components and formation of the diastereomeric mixtures of the terpene-amino acids hybrids, with diastereomeric excess varying from 0 to 100%...
September 28, 2016: Steroids
Martina Letizia Contente, Benedetta Guidi, Immacolata Serra, Valerio De Vitis, Diego Romano, Andrea Pinto, Roberto Lenna, Ricardo Pinheiro de Souza Oliveira, Francesco Molinari
A high yielding bioprocess for 11-α hydroxylation of canrenone (1a) using Aspergillus ochraceus ATCC 18500 was developed. The optimization of the biotransformation involved both fermentation (for achieving highly active mycelium of A. ochraceus) and biotransformation with the aim to obtain 11-α hydroxylation with high selectivity and yield. A medium based on sucrose as C-source resulted particularly suitable for conversion of canrenone into the corresponding 11-hydroxy derivative, whereas the use of O2-enriched air and dimethyl sulfoxide (DMSO) as a co-solvent for increasing substrate solubility played a crucial role for obtaining high yields (>95%) of the desired product in high chemical purity starting from 30mM (10...
September 22, 2016: Steroids
Mihalj Poša, Ana Pilipović, Mirjana Bećarević, Zita Farkaš
Due to a relatively small size of bile acid salts, their mixed micelles with nonionic surfactants are analysed. Of the special interests are real binary mixed micelles that are thermodynamically more stable than ideal mixed micelles. Thermodynamic stability is expressed with an excess Gibbs energy (G(E)) or over an interaction parameter (βij). In this paper sodium salts of cholic (C) and hiodeoxycholic acid (HD) in their mixed micelles with Tween 40 (T40) are analysed by potentiometric titration and their pKa values are determined...
September 17, 2016: Steroids
Martina Wimmerová, Věra Siglerová, David Šaman, Miroslav Šlouf, Eva Kaletová, Zdeněk Wimmer
Naturally occurring acylated β-sitosteryl glucosides have been investigated for their novel properties. The synthetic protocol based on the literature data was improved and optimized. The main improvement consists in employing systems of ionic liquids combined with organic solvents in lipase-mediated esterification of (3β)-stigmast-5-en-3-yl β-d-glucopyranoside to get (3β)-stigmast-5-en-3-yl 6-O-acyl-β-d-glucopyranosides. Maximum yields of these products were achieved with Candida antarctica lipase B immobilized on Immobead 150, recombinant from yeast, in absolute THF and in the presence of either ionic liquid [1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM]BF4) or 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM]PF6)] employed...
September 17, 2016: Steroids
Agnieszka Wojtkielewicz, Paulina Uścinowicz, Leszek Siergiejczyk, Urszula Kiełczewska, Artur Ratkiewicz, Jacek W Morzycki
The condensation of 16-dehydropregnenolone acetate with 2-aminobenzimidazole was studied. The polycyclic aromatic product was formed as a single regioisomer in a cascade reaction comprising addition, cyclization, autoxidation, and aromatization, in addition to the rearranged D-homo product. The reaction mechanism based on DFT calculations is proposed.
September 16, 2016: Steroids
Lukáš Huml, Michal Jurášek, Petra Mikšátková, Tomáš Zimmermann, Pavla Tomanová, Miloš Buděšínský, Zdeňka Rottnerová, Markéta Šimková, Juraj Harmatha, Eva Kmoníčková, Oldřich Lapčík, Pavel B Drašar
Trilobolide (Tb) is a pharmacologically interesting sesquiterpene lactone isolated from Laser trilobum (L.) Borkh. Structural relation to a sarco/endoplasmic reticulum Ca(2+)-ATPase inhibitor thapsigargin bring promising prospects for Tb to be used in the development of new anti-cancer drugs. As long as there are still unanswered questions regarding its investigation, a need for novel analytical tools emerge. Since immunoassays serve as one of powerful tools within the investigation of natural products, the development of indirect competitive enzyme-linked immunosorbent assay (ELISA) utilizing coating based on avidin-biotin technology is described...
September 4, 2016: Steroids
Waya S Phutdhawong, Wanwikar Ruensamran, Weerachai Phutdhawong
Preparation of synthetic analogues of 28-homobrassinosteroids is reported. Also, the addition of the 28-homocastasterone at the C6 carbonyl group via allyl Gringard reagent followed by olefin cross metathesis resulted in dimeric analogues. Rice lamina inclination assay showed that the replacement of the C6 carbonyl group by 6α-allyl and 6β hydroxyl groups led to a decrease in bioactivity, whereas the dimeric analogues showed a reduced but significant bioactivity when compared to the 28-homocastasterone.
August 24, 2016: Steroids
Santosh Kumar Adla, Barbora Slavikova, Marketa Smidkova, Eva Tloustova, Martin Svoboda, Vojtech Vyklicky, Barbora Krausova, Pavla Hubalkova, Michaela Nekardova, Kristina Holubova, Karel Vales, Milos Budesinsky, Ladislav Vyklicky, Hana Chodounska, Eva Kudova
Herein, we report a new class of amide-based inhibitors (1-4) of N-methyl-d-aspartate receptors (NMDARs) that were prepared as analogues of pregnanolone sulfate (PAS) and pregnanolone glutamate (PAG) - the steroidal neuroprotective NMDAR inhibitors. A series of experiments were conducted to evaluate their physicochemical and biological properties: (i) the inhibitory effect of compounds 3 and 4 on NMDARs was significantly improved (IC50=1.0 and 1.4μM, respectively) as compared with endogenous inhibitor - pregnanolone sulfate (IC50=24...
August 17, 2016: Steroids
Michal Jurášek, Petr Džubák, Silvie Rimpelová, David Sedlák, Petr Konečný, Ivo Frydrych, Soňa Gurská, Marián Hajdúch, Kateřina Bogdanová, Milan Kolář, Tomáš Müller, Eva Kmoníčková, Tomáš Ruml, Juraj Harmatha, Pavel B Drašar
Sesquiterpene lactone trilobolide is a sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) inhibitor, thus depleting the Ins(1,4,5)P3-sensitive intracellular calcium stores. Here, we describe a synthesis of a series of 6 trilobolide-steroids conjugates (estradiol, pregnene, dehydroepiandrosterone, and testosterone). We found that the newly synthesized Tb-based compounds possess different remarkable biological activities. Cancer cell cytotoxicity and preferential selectivity is represented in our study by a Tb-pregnene derivative...
August 17, 2016: Steroids
Tatyana S Khlebnicova, Yuri A Piven, Alexander V Baranovsky, Fedor A Lakhvich, Svetlana V Shishkina, Daina Zicāne, Zenta Tetere, Irisa Rāviņa, Viktors Kumpiņš, Inese Rijkure, Inese Mieriņa, Uldis Peipiņš, Māris Turks
An efficient protocol for the synthesis of novel lupane triterpenoid-indazolone hybrids with oxime ester linkage has been developed from naturally accessible precursor betulin. For the first time a series of betulonic acid-indazolone hybrids have been synthesized via an acylation of corresponding 6,7-dihydro-1H-indazol-4(5H)-one oximes with betulonic acid chloride. Diastereoselective reduction of the obtained betulonic acid conjugates with NaBH4 resulted in a formation of betulinic acid-indazolone hybrids in excellent yields...
August 5, 2016: Steroids
Martha C Mayorquín-Torres, Rafael Arcos-Ramos, Marcos Flores-Álamo, Martín A Iglesias-Arteaga
Crystalline derivatives of side chain modified bile acids were efficiently prepared from the naturally occurring steroids by palladium-catalyzed cross coupling reaction as a key step. The solvent-free crystalline bile acids derivatives 2b-e are readily accessed by slow evaporation from selected solvents. A variety of steroidal scaffolds were found and elucidated by SXRD studies. The crystal packing of the title compounds are dominated by hydrogen-bonding interactions established between differently positioned acetyl protecting groups, which in the case of 2b and 2e take advantage of the facial amphiphilicity producing two novel steroidal supramolecular self-assemblies combining π-π and strong facial interactions...
November 2016: Steroids
Juan M Rodriguez, Matías Monsalves-Alvarez, Sandra Henriquez, Miguel N Llanos, Rodrigo Troncoso
Glucocorticoids are involved in several responses triggered by a variety of environmental and physiological stimuli. These hormones have a wide-range of regulatory effects in organisms. Synthetic glucocorticoids are extensively used to suppress allergic, inflammatory, and immune disorders. Although glucocorticoids are highly effective for therapeutic purposes, some patients chronically treated with glucocorticoids can develop reduced glucocorticoid sensitivity or even resistance, increasing patient vulnerability to exaggerated inflammatory responses...
November 2016: Steroids
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"