Strategy for the vibrational circular dichroism study of a glycosylflavonoid evaluated as its peracetate. The case of bioactive 7-O-β-D-glucopyranosylchrysin
Abstract As it is difficult to study polyhydroxylated natural products by vibrational circular dichroism (VCD) due to their very limited solubility in infrared transparent solvents, 7-O-β-D-glucopyranosylchrysin (1), isolated from Mimosa rosei, was acetylated to provide 7-O-(2ʹʹ,3ʹʹ,4ʹʹ,6ʹʹ-tetraacetyl-β-D-glucopyranosyl)-5-acetylchrysin (2). Density functional theory (DFT) VCD spectra of 2 were calculated using the B3LYP, B3PW91, and PBEPBE functionals and the DGDZVP basis set to ascertain a good level of theory for calculating this kind of compounds. Statistical comparison of the experimental and calculated VCD spectra revealed that the frequently employed B3LYP and B3PW91 functionals provided good confidence levels with similar statistical results, allowing band assignments for the pyranoside portion of 2. This is the first report on a satisfactory statistical validation of a VCD measurement for such a glycopyranoside. In addition, in vitro cytotoxicity studies of 1 and 2 against the human colon cell line HT-29 and the human melanoma cell line UACC-62 by the MTT method were assayed. Moreover, the immunomodulatory response of 1 and 2 was evaluated by measuring TNF-α, IL-1β, and IL-10 levels by the ELISA technique. The results revealed low cytotoxicity of both compounds against cancer cells. However, flavonoid 1 upregulated the IL-1β production in lipopolysaccharide (LPS)-induced THP-1 macrophage, thus suggesting the potential of this molecule as an immunostimulant for cancer treatment.
Last. Gabriel Cuevas(UNAM: National Autonomous University of Mexico)H-Index: 21
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Abstract The M06–2X, B3LYP, ωB97XD and B97D functionals with the 6–311++G(2d,2p) and DGDZVP basis sets were used to describe the stationary points of minimum energy of the potential energy surface of perezone. The inability of theoretical methods to predict a consistent conformational order, including the effects of zero point energy and dielectric constant was highlighted. Perezone was used as a model of study since it is known that weak interactions are involved in its conformation and represe...
Last. Rosa E. del Río(UMSNH: Universidad Michoacana de San Nicolás de Hidalgo)H-Index: 12
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: Although podocephalol (1) and its derived acetate 2 were found in Lasianthaea podocephala four decades ago, and 1 was later detected in the essential oils of several vegetal species, its absolute configuration (AC) and conformational preferences remained to be established. The structures of ar-himachalene 1, now isolated from Lasianthaea aurea, and its derived acetate 2, were herein confirmed by extensive 1D and 2D nuclear magnetic resonance (NMR) studies, while the conformational preferences ...
Costimulatory signals initiated by the interaction between the tumor necrosis factor (TNF) ligand and cognate TNF receptor (TNFR) superfamilies promote clonal expansion, differentiation, and survival of antigen-primed CD4+ and CD8+ T cells and have a pivotal role in T-cell-mediated adaptive immunity and diseases. Accumulating evidence in recent years indicates that costimulatory signals via the subset of the TNFR superfamily molecules, OX40 (TNFRSF4), 4-1BB (TNFRSF9), CD27, DR3 (TNFRSF25), CD30 ...
// Eva Hajek 1 , Franziska Krebs 1 , Rebekka Bent 1 , Katharina Haas 1 , Antje Bast 2 , Ivo Steinmetz 2 , Andrea Tuettenberg 1 , Stephan Grabbe 1, * and Matthias Bros 1, * 1 Department of Dermatology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany 2 Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany * These authors contributed eqully to this work Correspondence to: Stephan Grabbe, email: stephan.grabbe@unimedi...
ABSTRACTCytokines regulate virtually aspects of innate and adaptive immunity, including the initiation, execution and extinction of tumor-targeting immune responses. Over the past three decades, the possibility of using recombinant cytokines as a means to elicit or boost clinically relevant anticancer immune responses has attracted considerable attention. However, only three cytokines have been approved so far by the US Food and Drug Administration and the European Medicines Agency for use in ca...
#2Julio C. Pardo-Novoa(UMSNH: Universidad Michoacana de San Nicolás de Hidalgo)H-Index: 2
Last. Mario A. Gómez-Hurtado(UMSNH: Universidad Michoacana de San Nicolás de Hidalgo)H-Index: 8
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A methodology to determine the enantiomeric excess and the absolute configuration (AC) of natural epoxythymols was developed and tested using five constituents of Ageratina glabrata. The methodology is based on enantiomeric purity determination employing 1,1′-bi-2-naphthol (BINOL) as a chiral solvating agent combined with vibrational circular dichroism (VCD) measurements and calculations. The conformational searching included an extensive Monte Carlo protocol that considered the rotational barri...
Last. Hossein Hosseinzadeh(MUMS: Mashhad University of Medical Sciences)H-Index: 79
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Abstract Inflammation and the pro-inflammatory cytokines are associated with numerous chronic diseases. Studies suggest that flavonoids, plant polyphenolic compound derivatives from natural origin, have a wide range of putative biological activities. Similar to other flavonoids, chrysin (CH) by its anti-oxidative and anti-inflammatory effects is a potential prophylactic agent in immunopathological and physicochemical injuries. This is an overview on putative immunomodulatory activities of flavon...
A reliable and convenient method for determining the configuration and conformation of the furanose ring in carbohydrates and nucleosides by vibrational circular dichroism (VCD) spectroscopy is described. Diastereomeric pairs of several furanose monosaccharides and nucleosides were prepared, and their VCD spectra were analyzed. The results revealed that VCD spectroscopy elucidates the equibrated state of the furanose ring puckers, which is often difficult to study by other techniques.
Last. Rosa E. del Río(UMSNH: Universidad Michoacana de San Nicolás de Hidalgo)H-Index: 12
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The aerial parts of Ageratina glabrata afforded (−)-(3S,4R,5R,6S)-3,5,6-trihydroxy-1-menthene 3-O-β-d-glucopyranoside (1) and (−)-(3S,4S,6R)-3,6-dihydroxy-1-menthene 3-O-β-d-glucopyranoside (3). Acid hydrolysis of 1 yielded (+)-(1R,4S,5R,6R)-1,5,6-trihydroxy-2-menthene (5) and (+)-(1S,4S,5R,6R)-1,5,6-trihydroxy-2-menthene (6), while hydrolysis of 3 yielded (+)-(3S,4S,6R)-3,6-dihydroxy-1-menthene (10), (+)-(1R,4S,6R)-1,6-dihydroxy-2-menthene (11), and (+)-(1S,4S,6R)-1,6-dihydroxy-2-menthene (12)....
We present the first implementation of the vibrational circular dichroism (VCD) spectrum of large molecules through the Molecules-in-Molecules (MIM) fragment-based method. An efficient projection of the relevant higher energy derivatives from smaller fragments to the parent molecule enables the extension of the MIM method for the evaluation of VCD spectra (MIM-VCD). The overlapping primary subsystems in this work are constructed from interacting fragments using a number-based scheme and the dang...
Abstract Fusidic acid (1a) is a commercial antibiotic widely used in therapy for methicillin-resistant Staphylococcus aureus infections. Although the history of spectroscopic and conformational characteristics of 1a is long and old, the complete 1H NMR parameters set assignment remains incomplete due to the large signal superposition in most conventionally used NMR spectrometers. Thus, in the present study the 750 MHz 1H NMR spectra of the two methyl acetylfusidates 1b and 1c were completely ass...