scholarly journals Hybrid Multivalent Jack Bean α-Mannosidase Inhibitors: The First Example of Gold Nanoparticles Decorated with Deoxynojirimycin Inhitopes

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5864
Author(s):  
Costanza Vanni ◽  
Anne Bodlenner ◽  
Marco Marradi ◽  
Jérémy P. Schneider ◽  
Maria de los Angeles Ramirez ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Inhibitory Activity ◽  
Gold Surface ◽  
Aliphatic Chain ◽  
Monomeric Form ◽  
Reference Compound ◽  
Jack Bean ◽  
Processing Enzymes ◽  
Water Dispersible ◽  
Nanomolar Range

Among carbohydrate-processing enzymes, Jack bean α-mannosidase (JBα-man) is the glycosidase with the best responsiveness to the multivalent presentation of iminosugar inhitopes. We report, in this work, the preparation of water dispersible gold nanoparticles simultaneously coated with the iminosugar deoxynojirimycin (DNJ) inhitope and simple monosaccharides (β-d-gluco- or α-d-mannosides). The display of DNJ at the gold surface has been modulated (i) by using an amphiphilic linker longer than the aliphatic chain used for the monosaccharides and (ii) by presenting the inhitope, not only in monomeric form, but also in a trimeric fashion through combination of a dendron approach with glyconanotechnology. The latter strategy resulted in a strong enhancement of the inhibitory activity towards JBα-man, with a Ki in the nanomolar range (Ki = 84 nM), i.e., more than three orders of magnitude higher than the monovalent reference compound.

scholarly journals Synthesis of 1,4-imino-L-lyxitols modified at C-5 and their evaluation as inhibitors of GH38 α-mannosidases

2018 ◽  
Vol 14 ◽  
pp. 2156-2162 ◽  
Author(s):  
Maroš Bella ◽  
Sergej Šesták ◽  
Ján Moncoľ ◽  
Miroslav Koóš ◽  
Monika Poláková
Keyword(s):  
Drosophila Melanogaster ◽  
Inhibitory Activity ◽  
Synthetic Approach ◽  
Jack Bean ◽  
Canavalia Ensiformis ◽  
Inhibition Effect ◽  
No Inhibition

A synthetic approach to 1,4-imino-L-lyxitols with various modifications at the C-5 position is reported. These imino-L-lyxitol cores were used for the preparation of a series of N-(4-halobenzyl)polyhydroxypyrrolidines. An impact of the C-5 modification on the inhibition and selectivity against GH38 α-mannosidases from Drosophila melanogaster, the Golgi (GMIIb) and lysosomal (LManII) mannosidases and commercial jack bean α-mannosidase from Canavalia ensiformis was evaluated. The modification at C-5 affected their inhibitory activity against the target GMIIb enzyme. In contrast, no inhibition effect of the pyrrolidines against LManII was observed. The modification of the imino-L-lyxitol core is therefore a suitable motif for the design of inhibitors with desired selectivity against the target GMIIb enzyme.

scholarly journals Surface Adsorption of the Alpha-Emitter Astatine-211 to Gold Nanoparticles Is Stable In Vivo and Potentially Useful in Radionuclide Therapy

2021 ◽  
Vol 2 (4) ◽  
pp. 196-207
Author(s):  
Emanuel Sporer ◽  
Christian B. M. Poulie ◽  
Sture Lindegren ◽  
Emma Aneheim ◽  
Holger Jensen ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Surface Adsorption ◽  
Radiochemical Yield ◽  
Gold Surface ◽  
Mouse Serum ◽  
Control Group ◽  
Alpha Emitter ◽  
Before And After ◽  
The Stability

Targeted α-therapy (TAT) can eradicate tumor metastases while limiting overall toxicity. One of the most promising α-particle emitters is astatine-211 (211At). However, 211At-carbon bonds are notoriously unstable in vivo and no chelators are available. This hampers its adoption in TAT. In this study, the stability of 211At on the surface of gold nanoparticles (AuNPs) was investigated. The employed AuNPs had sizes in the 25–50 nm range. Radiolabeling by non-specific surface-adsorption in >99% radiochemical yield was achieved by mixing 211At and AuNPs both before and after polyethylene glycol (PEG) coating. The resulting 211At-AuNPs were first challenged by harsh oxidation with sodium hypochlorite, removing roughly 50% of the attached 211At. Second, incubation in mouse serum followed by a customized stability test, showed a stability of >95% after 4 h in serum. This high stability was further confirmed in an in vivo study, with comparison to a control group of free 211At. The AuNP-associated 211At showed low uptake in stomach and thyroid, which are hallmark organs of uptake of free 211At, combined with long circulation and high liver and spleen uptake, consistent with nanoparticle biodistribution. These results support that gold surface-adsorbed 211At has high biological stability and is a potentially useful delivery system in TAT.

THEVETIA PERUVIANA ROOTS EXTRACT MEDICATED GOLD NANOPARTICLES AND ITS UREASE INHIBITORY ACTIVITY

2021 ◽  
pp. 79-82
Author(s):  
SAUD BAWAZEER
Keyword(s):  
Gold Nanoparticles ◽  
Aqueous Extract ◽  
Inhibitory Activity ◽  
Enzyme Inhibitor ◽  
Research Work ◽  
Thevetia Peruviana ◽  
Urease Enzyme ◽  
Urease Inhibitory ◽  
Microscopy Techniques

Objective: The main objective of the current research work was synthesized of gold nanoparticles (AuNPs) of Thevetia peruviana aqueous extract,characterization, and screening for urease enzyme inhibitory activity.Methods: AuNPs were synthesized by mixing 1 mM gold salt solution with T. peruviana aqueous extract without any reducing agents. The preparedAuNPs were characterized using UV–visible spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy techniques. Thesynthesized AuNPs were assessed for in vitro urease enzyme inhibitory activity at 0.2 μg in comparison with the aqueous extract.Results: In this finding, we synthesized the AuNPs of T. peruviana aqueous extract for the 1st time. The AuNPs exhibited significant stability atroom temperature. The AuNPs showed significant urease inhibitory activity with IC50 67.56±1.67 at 0.2 μg as compared to aqueous extract whichexhibited good activity with IC50 39.21±1.32 μ at 0.2 mg, against standard thiourea (IC50=21.00±1.16). The formation of AuNPs correlates due to activephytochemical present in extract which is responsible for synthesizing NPs.Conclusion: T. peruviana extract and prepared AuNPs are an outstanding urease enzyme inhibitor and are capable of making fine NPs. Application:The synthesized AuNPs of T. peruviana aqueous extract which significant urease inhibitory activity may allow us to discover NPs for potentiallyeffective and safe nanoherbal therapy.

scholarly journals Functionalization of Gold Nanoparticles by Inorganic Entities

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 548 ◽  
Author(s):  
Frédéric Dumur ◽  
Eddy Dumas ◽  
Cédric R. Mayer
Keyword(s):  
Gold Nanoparticles ◽  
Rapid Development ◽  
Gold Surface ◽  
Intrinsic Properties ◽  
Au Nps ◽  
Gold Core ◽  
Inorganic Systems ◽  
Wide Range ◽  
Different Types ◽  
Electron Donating Groups

The great affinity of gold surface for numerous electron-donating groups has largely contributed to the rapid development of functionalized gold nanoparticles (Au-NPs). In the last years, a new subclass of nanocomposite has emerged, based on the association of inorganic molecular entities (IME) with Au-NPs. This highly extended and diversified subclass was promoted by the synergy between the intrinsic properties of the shell and the gold core. This review—divided into four main parts—focuses on an introductory section of the basic notions related to the stabilization of gold nanoparticles and defines in a second part the key role played by the functionalizing agent. Then, we present a wide range of inorganic molecular entities used to prepare these nanocomposites (NCs). In particular, we focus on four different types of inorganic systems, their topologies, and their current applications. Finally, the most recent applications are described before an overview of this new emerging field of research.

scholarly journals Preparation of a Highly Water-dispersible Powder Containing Hydrophobic Polyphenols Derived from Chrysanthemum Flower with Xanthine Oxidase-inhibitory Activity

2018 ◽  
Vol 24 (2) ◽  
pp. 273-281
Author(s):  
Kazunori Kadota ◽  
Mie Hashimoto ◽  
Takao Yamaguchi ◽  
Hideo Kawachi ◽  
Hiromasa Uchiyama ◽  
...  
Keyword(s):  
Xanthine Oxidase ◽  
Inhibitory Activity ◽  
Water Dispersible

LC-MS- and NMR-Guided Isolation of Monoterpene Dimers from Cultivated Thymus vulgaris Varico 3 Hybrid and Their Antityrosinase Activity

Planta Medica ◽  
2019 ◽  
Vol 85 (11/12) ◽  
pp. 941-946 ◽  
Author(s):  
Ilias Stefanis ◽  
Dimitra Hadjipavlou-Litina ◽  
Anna-Rita Bilia ◽  
Anastasia Karioti
Keyword(s):  
Ursolic Acid ◽  
Oleanolic Acid ◽  
Inhibitory Activity ◽  
Kojic Acid ◽  
2D Nmr ◽  
Thymus Vulgaris ◽  
Reference Compound ◽  
Aerial Parts ◽  
Spectroscopic Analyses ◽  
Antityrosinase Activity

AbstractTargeted isolation based on a combination of NMR and HPLC-PDA-MS of a dichloromethane extract of Thymus vulgaris Varico 3 aerial parts afforded one new p-cymene dimer, 6,3′,4′-trihydroxy-5,5′-diisopropyl-2,2′-dimethylbiphenyl (1), together with two known p-cymene derivatives (2 and 3), as well as five known compounds, namely, thymol (4), oleanolic acid (5), ursolic acid (6), cirsimaritin (7), and xanthomicrol (8). The structural elucidation of all compounds was performed by spectroscopic analyses, including 1D and 2D NMR, and HRESIMS experiments. The biphenyls were assayed for their inhibitory activity on tyrosinase. Compounds 2 and 3 showed negligible activity on tyrosinase, while compound 1 effectively inhibited the enzyme with 35% (± 0.3) inhibitory activity, higher than the inhibition of the reference compound kojic acid (18.6 ± 0.02).

scholarly journals A Hydrophobic Gold Surface Triggers Misfolding and Aggregation of the Amyloidogenic Josephin Domain in Monomeric Form, While Leaving the Oligomers Unaffected

PLoS ONE ◽  
2013 ◽  
Vol 8 (3) ◽  
pp. e58794 ◽  
Author(s):  
Alessandra Apicella ◽  
Monica Soncini ◽  
Marco Agostino Deriu ◽  
Antonino Natalello ◽  
Marcella Bonanomi ◽  
...  
Keyword(s):  
Gold Surface ◽  
Monomeric Form

Distance Controlled and Electrically Driven Photoluminescence Quench From Quantum Dot-Au Complexes

2010 ◽  
Vol 1257 ◽  
Author(s):  
Zhitao Kang ◽  
Jie Xu ◽  
Dinal Andreasen ◽  
Brent Karl Wagner
Keyword(s):  
Gold Nanoparticles ◽  
Protein Interactions ◽  
Near Infrared ◽  
Incident Light ◽  
Gold Surface ◽  
Electric Signal ◽  
Protein Protein Interactions ◽  
Quenching Effect ◽  
Quenching Efficiency ◽  
Pl Quenching

AbstractQuantum Dots (QDs) bound to gold nanoparticles have shown photoluminescence (PL) quenching dependent on distance between the two particles. The incident light from the QD couples to plasmon excitation of the metal when the frequencies of the light and the surface plasmon resonance (SPR) coincide, leading to a reduction in emitted PL in the system. The quenching effect of gold nanoparticles on QDs was used to study protein-protein interactions with the potential for drug screening applications. CdTe and CdHgTe QDs with emission wavelengths from 500˜900nm were synthesized and gold nanospheres and nanorods with controlled absorption in the visible and near-infrared (NIR) wavelength regions were prepared. The PL quenching of QD-Protein-Protein-Au complexes was studied as a function of Au concentration, QD size and protein type. A quenching efficiency of up to 90% was observed. The QD-Au complexes were also studied for electric potential sensing. The surface of the QDs was negatively charged due to thiol ligands capping. By applying a positive potential on the gold or gold nanoparticle attached substrate, the local electric field between the substrate and the statically charged QDs would pull the QDs closer to the gold surface and quench the QD PL. PL quenching of QD with Au was studied as a function of electric signal and QD type. In this methodology, electric signals were effectively converted to optical signals.

Ligand Density Effect on Biorecognition by PEGylated Gold Nanoparticles:  Regulated Interaction of RCA120Lectin with Lactose Installed to the Distal End of Tethered PEG Strands on Gold Surface

2005 ◽  
Vol 6 (2) ◽  
pp. 818-824 ◽  
Author(s):  
Seiji Takae ◽  
Yoshitsugu Akiyama ◽  
Hidenori Otsuka ◽  
Teisaku Nakamura ◽  
Yukio Nagasaki ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Gold Surface ◽  
Density Effect ◽  
Ligand Density

FORMATION OF GOLD NANOPARTICLES/OLIGOTHIOPHENE DITHIOLS COMPOSITE THIN FILMS BETWEEN MICROGAPPED GOLD ELECTRODES AND THEIR ELECTRONIC PROPERTIES

2002 ◽  
Vol 01 (05n06) ◽  
pp. 557-562 ◽  
Author(s):  
SEISUKE MAEDA ◽  
TAKUJI OGAWA
Keyword(s):  
Gold Nanoparticles ◽  
Coulomb Blockade ◽  
Gold Electrode ◽  
Quartz Crystal ◽  
Gold Surface ◽  
Crystal Oscillator ◽  
Tunneling Mechanism ◽  
Straight Line ◽  
Current Voltage ◽  
Lower Temperature

We have studied the construction and electronic characteristics of a series of devices made from gold microgap electrodes, gold nanoparticles and conjugated oligothiophene dithiols. The formations of gold nanoparticle/oligothiophene dithiol composites on gold surface were monitored by quartz crystal microbalance (QCM) using gold electrode coated crystal oscillator. The formation speed was the fastest for terthiophene dithiol followed by hexathiophene and nanothiophene dithiols, the latter two showed almost the same formation speed. The current–voltage (I/V) curves of these devices were measured at various temperatures to show that at high temperature (>200 K) they were almost straight line; at lower temperature they became parabolic, and at 4 K a completely blocked region appeared between -12 to +12 V. We attributed the parabolic I/V curve to a tunneling mechanism and the blocked region to the Coulomb blockade phenomena.

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