Search results for " Screening"
showing 10 items of 898 documents
Three New Triterpene Saponins from Two Species of Carpolobia
2002
Three new acetylated triterpene saponins 1-3 were isolated from the roots of Carpolobia alba and C. lutea. Their structures were established mainly by 2D NMR techniques as 3-O-beta-D-glucopyranosylpresenegenin-28-O-beta-D-galactopyranosyl-(1-->4)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-(3,4-di-O-acetyl)-beta-D-fucopyranosyl ester, 3-O-beta-D-glucopyranosylpresenegenin-28-O-beta-D-galactopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->3)]-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-(3,4-di-O-acetyl)-beta-D-fucopyranosyl ester, and 3-O-beta-D-glucopyranosylpresenegenin-28-O-beta-D-xylopyranosyl-(1-->4)-[beta-D-apiofuranosyl…
Antiproliferative Oleanane Saponins from Meryta denhamii
2008
Eight new oleanane saponins (1- 8) together with four know saponins (9-12) were isolated from the aerial parts of Meryta denhamii. Their structures were elucidated by 1D and 2D NMR experiments including 1D TOCSY, DQF-COSY, ROESY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis. The antiproliferative activity of all compounds was evaluated using three murine and human cancer cell lines: J774.A1, HEK-293, and WEHI-164.
Water-soluble isoindolo[2,1-a]quinoxalin-6-imines: In vitro antiproliferative activity and molecular mechanism(s) of action
2015
Abstract Water-soluble isoindoloquinoxalin (IIQ) imines and the corresponding acetates were conveniently prepared from the key intermediates 2-(2′-aminophenyl)-2H-isoindole-1-carbonitriles obtained by a Strecker reaction between substituted 1,2-dicarbaldehydes and 1,2-phenylenediamines. Both series were screened by the National Cancer Institute (Bethesda, MD) and showed potent antiproliferative activity against a panel of 60 human tumor cell lines. Several of the novel compounds showed GI50 values at a nanomolar level on the majority of the tested cell lines. Among IIQ derivatives, methoxy substituents at positions 3 and 8 or/and 9 were especially effective in impairing cell cycle progressi…
Steroidal saponins from Chlorophytum orchidastrum.
2009
Six new spirostane-type saponins (1−6), named orchidastrosides A−F, and chloromaloside D were isolated from an ethanol extract of the roots of Chlorophytum orchidastrum. The saponins have neotigogenin or neogitogenin as the aglycon and oligosaccharidic chains possessing seven to nine sugar units. Their structures were elucidated mainly by 2D NMR spectroscopic analyses (COSY, TOCSY, NOESY, HSQC, and HMBC) and FABMS and HRESIMS. Compounds 1−6 were tested for cytotoxicity against two human colon cancer cell lines, HCT 116 and HT-29.
Stereocontrol in Diphenylprolinol Silyl Ether Catalyzed Michael Additions : Steric Shielding or Curtin-Hammett Scenario?
2017
The enantioselectivity of amine-catalyzed reactions of aldehydes with electrophiles is often explained by simple steric arguments emphasizing the role of the bulky group of the catalyst that prevents the approach of the electrophile from the more hindered side. This standard steric shielding model has recently been challenged by the discovery of stable downstream intermediates, which appear to be involved in the rate-determining step of the catalytic cycle. The alternative model, referred to as Curtin-Hammett scenario of stereocontrol, assumes that the enantioselectivity is related to the stability and reactivity of downstream intermediates. In our present computational study, we examine th…
Are credit screening contracts designed for men?
2022
AbstractAccess to credit is key to succeed in business. Theoretical models of credit under asymmetric information classify borrowers and grant or deny credit, typically based on incentive-compatible contracts with collateral. However, if women are particularly risk averse, female borrowers may be wrongly classified and denied credit. We conduct in three countries a laboratory experiment to study this systematic gender difference. Results show that incentive-compatible contracts with collateral fail to disclose women’s private information, while disclosing men’s private information. We suggest that banks should incorporate the gender difference in risk attitudes to avoid the glass ceiling in…
Multicellular tumor spheroids: an underestimated tool is catching up again.
2009
The present article highlights the rationale, potential and flexibility of tumor spheroid mono- and cocultures for implementation into state of the art anti-cancer therapy test platforms. Unlike classical monolayer-based models, spheroids strikingly mirror the 3D cellular context and therapeutically relevant pathophysiological gradients of in vivo tumors. Some concepts for standardization and automation of spheroid culturing, monitoring and analysis are discussed, and the challenges to define the most convenient analytical endpoints for therapy testing are outlined. The potential of spheroids to contribute to either the elimination of poor drug candidates at the pre-animal and pre-clinical …
A convolutional neural network for virtual screening of molecular fingerprints
2019
In the last few years, Deep Learning (DL) gained more and more impact on drug design because it allows a huge increase of the prediction accuracy in many stages of such a complex process. In this paper a Virtual Screening (VS) procedure based on Convolutional Neural Networks (CNN) is presented, that is aimed at classifying a set of candidate compounds as regards their biological activity on a particular target protein. The model has been trained on a dataset of active/inactive compounds with respect to the Cyclin-Dependent Kinase 1 (CDK1) a very important protein family, which is heavily involved in regulating the cell cycle. One qualifying point of the proposed approach is the use of molec…
The non-equilibrium charge screening effects in diffusion-driven systems with pattern formation.
2011
The effects of non-equilibrium charge screening in mixtures of oppositely charged interacting molecules on surfaces are analyzed in a closed system. The dynamics of charge screening and the strong deviation from the standard Debye-Huckel theory are demonstrated via a new formalism based on computing radial distribution functions suited for analyzing both short-range and long-range spacial ordering effects. At long distances the inhomogeneous molecular distribution is limited by diffusion, whereas at short distances (of the order of several coordination spheres) by a balance of short-range (Lennard-Jones) and long-range (Coulomb) interactions. The non-equilibrium charge screening effects in …
Synthesis of Fluorinated and Nonfluorinated Tebufenpyrad Analogues for the Study of Anti-angiogenesis MOA
2014
In this contribution we report the synthesis of fluorinated and nonfluorinated tebufenpyrad analogues to explore potential druglike properties through the phenotypic screening as part of the Lilly Open Innovation Drug Discovery (OIDD) program.