Fluorescent and Colorimetric Chemosensors for Anions, Metal Ions, Reactive Oxygen Species, Biothiols, and Gases

2016 ◽  
Vol 37 (10) ◽  
pp. 1661-1678 ◽  
Author(s):  
Yifan Liu ◽  
Ying Hu ◽  
Songyi Lee ◽  
Dayoung Lee ◽  
Juyoung Yoon
Keyword(s):  
Reactive Oxygen Species ◽  
Metal Ions ◽  
Reactive Oxygen ◽  
Oxygen Species

Amentoflavone: A Bifunctional Metal Chelator that Controls the Formation of Neurotoxic Soluble Aβ42 Oligomers

2020 ◽  
Author(s):  
Liang Sun ◽  
Anuj K. Sharma ◽  
Byung-Hee Han ◽  
Liviu M. Mirica
Keyword(s):  
Reactive Oxygen Species ◽  
Metal Ions ◽  
Antioxidant Properties ◽  
Reactive Oxygen ◽  
Amyloid Plaques ◽  
Transition Metal Ions ◽  
Oxygen Species ◽  
High Affinity ◽  
Amyloid Aβ ◽  
Β Amyloid

<p>Alzheimer's disease (AD) is the most common neurodegenerative disorder, yet the cause and progression of this disorder are not completely understood. While the main hallmark of AD is the deposition of amyloid plaques consisting of the β-amyloid (Aβ) peptide, transition metal ions are also known to play a significant role in disease pathology by expediting the formation of neurotoxic soluble β-amyloid (Aβ) oligomers, reactive oxygen species (ROS), and oxidative stress. Thus, bifunctional metal chelators that can control these deleterious properties are highly desirable. Herein, we show that amentoflavone (AMF) – a natural biflavonoid compound, exhibits good metal-chelating properties, especially for chelating Cu<sup>2+</sup> with very high affinity (pCu<sub>7.4</sub> = 10.44). In addition, AMF binds to Aβ fibrils with a high affinity (<i>K<sub>i</sub></i> = 287 ± 20 nM) – as revealed by a competition thioflavin T (ThT) assay, and specifically labels the amyloid plaques <i>ex vivo</i> in the brain sections of transgenic AD mice – as confirmed via immunostaining with an Ab antibody. The effect of AMF on Aβ<sub>42</sub> aggregation and disaggregation of Aβ<sub>42</sub> fibrils was also investigated, to reveal that AMF can control the formation of neurotoxic soluble Aβ<sub>42</sub> oligomers, both in absence and presence of metal ions, and as confirmed via cell toxicity studies. Furthermore, an ascorbate consumption assay shows that AMF exhibits potent antioxidant properties and can chelate Cu<sup>2+</sup> and significantly diminish the Cu<sup>2+</sup>-ascorbate redox cycling and reactive oxygen species (ROS) formation. Overall, these studies strongly suggest that AMF acts as a bifunctional chelator that can interact with various Aβ aggregates and reduce their neurotoxicity, can also bind Cu<sup>2+</sup> and mediate its deleterious redox properties, and thus AMF has the potential to be a lead compound for further therapeutic agent development for AD. </p>

Recent advances in semiconducting polymer dots as optical probes for biosensing

2021 ◽  
Author(s):  
Ye Yuan ◽  
Weiying Hou ◽  
Weiping Qin ◽  
Changfeng Wu
Keyword(s):  
Reactive Oxygen Species ◽  
Metal Ions ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Optical Probes ◽  
Semiconducting Polymer ◽  
Ph Values ◽  
Recent Advances ◽  
Polymer Dots ◽  
Semiconducting Polymer Dots

This review mainly summarized the recent results that used bright polymer dots (Pdots) for the detection of different analytes such as reactive oxygen species (ROS), metal ions, pH values, and a variety of biomolecules.

scholarly journals Generation of Reactive Oxygen Species by Interaction between Antioxidants Used as Food Additive and Metal Ions

2014 ◽  
Vol 55 (4) ◽  
pp. 167-176 ◽  
Author(s):  
Yusuke IWASAKI ◽  
Momoko ODA ◽  
Yuri TSUKUDA ◽  
Yuki NAGAMORI ◽  
Hiroyuki NAKAZAWA ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Metal Ions ◽  
Reactive Oxygen ◽  
Food Additive ◽  
Oxygen Species

Amentoflavone: A Bifunctional Metal Chelator that Controls the Formation of Neurotoxic Soluble Aβ42 Oligomers

2020 ◽  
Author(s):  
Liang Sun ◽  
Anuj K. Sharma ◽  
Byung-Hee Han ◽  
Liviu M. Mirica
Keyword(s):  
Reactive Oxygen Species ◽  
Metal Ions ◽  
Antioxidant Properties ◽  
Reactive Oxygen ◽  
Amyloid Plaques ◽  
Transition Metal Ions ◽  
Oxygen Species ◽  
High Affinity ◽  
Amyloid Aβ ◽  
Β Amyloid

<p>Alzheimer's disease (AD) is the most common neurodegenerative disorder, yet the cause and progression of this disorder are not completely understood. While the main hallmark of AD is the deposition of amyloid plaques consisting of the β-amyloid (Aβ) peptide, transition metal ions are also known to play a significant role in disease pathology by expediting the formation of neurotoxic soluble β-amyloid (Aβ) oligomers, reactive oxygen species (ROS), and oxidative stress. Thus, bifunctional metal chelators that can control these deleterious properties are highly desirable. Herein, we show that amentoflavone (AMF) – a natural biflavonoid compound, exhibits good metal-chelating properties, especially for chelating Cu<sup>2+</sup> with very high affinity (pCu<sub>7.4</sub> = 10.44). In addition, AMF binds to Aβ fibrils with a high affinity (<i>K<sub>i</sub></i> = 287 ± 20 nM) – as revealed by a competition thioflavin T (ThT) assay, and specifically labels the amyloid plaques <i>ex vivo</i> in the brain sections of transgenic AD mice – as confirmed via immunostaining with an Ab antibody. The effect of AMF on Aβ<sub>42</sub> aggregation and disaggregation of Aβ<sub>42</sub> fibrils was also investigated, to reveal that AMF can control the formation of neurotoxic soluble Aβ<sub>42</sub> oligomers, both in absence and presence of metal ions, and as confirmed via cell toxicity studies. Furthermore, an ascorbate consumption assay shows that AMF exhibits potent antioxidant properties and can chelate Cu<sup>2+</sup> and significantly diminish the Cu<sup>2+</sup>-ascorbate redox cycling and reactive oxygen species (ROS) formation. Overall, these studies strongly suggest that AMF acts as a bifunctional chelator that can interact with various Aβ aggregates and reduce their neurotoxicity, can also bind Cu<sup>2+</sup> and mediate its deleterious redox properties, and thus AMF has the potential to be a lead compound for further therapeutic agent development for AD. </p>

scholarly journals Hypothesis: Soluble AβOligomers in Association with Redox-Active Metal Ions Are the Optimal Generators of Reactive Oxygen Species in Alzheimer's Disease

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Brian J. Tabner ◽  
Jennifer Mayes ◽  
David Allsop
Keyword(s):  
Alzheimer’S Disease ◽  
Reactive Oxygen Species ◽  
Alzheimer's Disease ◽  
Hydrogen Peroxide ◽  
Metal Ions ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Redox Active ◽  
Active Metal ◽  
Redox Active Metal

Considerable evidence points to oxidative stress in the brain as an important event in the early stages of Alzheimer's disease (AD). The transition metal ions of Cu, Fe, and Zn are all enriched in the amyloid cores of senile plaques in AD. Those of Cu and Fe are redox active and bind to Aβin vitro. When bound, they can facilitate the reduction of oxygen to hydrogen peroxide, and of the latter to the hydroxyl radical. This radical is very aggressive and can cause considerable oxidative damage. Recent research favours the involvement of small, soluble oligomers as the aggregating species responsible for Aβ neurotoxicity. We propose that the generation of reactive oxygen species (i.e., hydrogen peroxide and hydroxyl radicals) by these oligomers, in association with redox-active metal ions, is a key molecular mechanism underlying the pathogenesis of AD and some other neurodegenerative disorders.

scholarly journals Different Reactive Oxygen Species Lead to Distinct Changes of Cellular Metal Ions in the Eukaryotic Model Organism Saccharomyces cerevisiae

2011 ◽  
Vol 12 (11) ◽  
pp. 8119-8132 ◽  
Author(s):  
Ming J. Wu ◽  
Patrick J. O’Doherty ◽  
Patricia A. Murphy ◽  
Victoria Lyons ◽  
Melinda Christophersen ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Reactive Oxygen Species ◽  
Metal Ions ◽  
Model Organism ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Cellular Metal
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