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Bacteriological Reviews Mar 1954
Topics: Amino Acids; Bacteria; Enzymes; Fermentation; Oxidation-Reduction
PubMed: 13140081
DOI: 10.1128/br.18.1.16-42.1954 -
Angewandte Chemie (International Ed. in... Jan 2023Alcohols and their derivatives are ubiquitous and versatile motifs in organic synthesis. Deoxygenative transformations of these compounds are often challenging due to... (Review)
Review
Alcohols and their derivatives are ubiquitous and versatile motifs in organic synthesis. Deoxygenative transformations of these compounds are often challenging due to the thermodynamic penalty associated with the cleavage of the C-O bond. However, electrochemically driven redox events have been shown to facilitate the C-O bond cleavage in alcohols and their derivatives either through direct electron transfer or through the use of electron transfer mediators and electroactive catalysts. Herein, a comprehensive overview of preparative electrochemically mediated protocols for C-O bond activation and functionalization is detailed, including direct and indirect electrosynthetic methods, as well as photoelectrochemical strategies.
Topics: Alcohols; Oxidation-Reduction; Electron Transport; Catalysis
PubMed: 36278406
DOI: 10.1002/anie.202211952 -
International Journal of Molecular... Aug 2015Photodynamic therapy (PDT) is a clinical modality used to treat cancer and infectious diseases. The main agent is the photosensitizer (PS), which is excited by light and... (Review)
Review
Photodynamic therapy (PDT) is a clinical modality used to treat cancer and infectious diseases. The main agent is the photosensitizer (PS), which is excited by light and converted to a triplet excited state. This latter species leads to the formation of singlet oxygen and radicals that oxidize biomolecules. The main motivation for this review is to suggest alternatives for achieving high-efficiency PDT protocols, by taking advantage of knowledge on the chemical and biological processes taking place during and after photosensitization. We defend that in order to obtain specific mechanisms of cell death and maximize PDT efficiency, PSes should oxidize specific molecular targets. We consider the role of subcellular localization, how PS photochemistry and photophysics can change according to its nanoenvironment, and how can all these trigger specific cell death mechanisms. We propose that in order to develop PSes that will cause a breakthrough enhancement in the efficiency of PDT, researchers should first consider tissue and intracellular localization, instead of trying to maximize singlet oxygen quantum yields in in vitro tests. In addition to this, we also indicate many open questions and challenges remaining in this field, hoping to encourage future research.
Topics: Animals; Cell Death; Humans; Oxidation-Reduction; Photochemistry; Photochemotherapy; Photosensitizing Agents
PubMed: 26334268
DOI: 10.3390/ijms160920523 -
Oxidative Medicine and Cellular... 2020
Topics: Animals; Antineoplastic Agents; Antioxidants; Biological Products; Humans; Neoplasms; Oxidation-Reduction; Oxidative Stress
PubMed: 32566077
DOI: 10.1155/2020/2407074 -
Seminars in Radiation Oncology Jan 2019Since the recognition during the 20 century that cancer cells demonstrated fundamental alterations in the regulation of oxidative and glycolytic metabolism, many basic...
Since the recognition during the 20 century that cancer cells demonstrated fundamental alterations in the regulation of oxidative and glycolytic metabolism, many basic as well as translational scientists have proposed that targeting metabolic differences in cancer versus normal cells could be exploited to improve cancer therapy outcomes. With the recognition that dysregulation of mitochondrial redox metabolism leads to the increased steady-state levels of superoxide and hydrogen peroxide which could contribute to both aging and cancer; radiation biologists have pursued many avenues of targeting oxidative metabolic pathways to both selectively radiosensitive cancer cells as well as protect normal tissues during cancer therapy. Recent advances in exploiting redox metabolism for improving radiochemotherapy both from a basic and translational science point of view are the focus of the papers in this current issue of . The historical perspective underlying these areas of research as well as a unifying hypothesis for further advancing this research into clinical trials will be presented in this overview.
Topics: Antioxidants; Chemoradiotherapy; Gene Expression Regulation, Neoplastic; Humans; Neoplasms; Oxidation-Reduction; Oxidative Stress; Signal Transduction
PubMed: 30573179
DOI: 10.1016/j.semradonc.2018.10.010 -
Biochimica Et Biophysica Acta 2013As discussed throughout this special issue, oxidation and reduction reactions play critical roles in the function of many organisms. In photosynthetic organisms, the... (Review)
Review
As discussed throughout this special issue, oxidation and reduction reactions play critical roles in the function of many organisms. In photosynthetic organisms, the conversion of light energy drives oxidation and reduction reactions through the transfer of electrons and protons in order to create energy-rich compounds. These reactions occur in proteins such as cytochrome c, a heme-containing water-soluble protein, the bacteriochlorophyll-containing reaction center, and photosystem II where water is oxidized at the manganese cluster. A critical measure describing the ability of cofactors in proteins to participate in such reactions is the oxidation/reduction midpoint potential. In this review, the basic concepts of oxidation/reduction reactions are reviewed with a summary of the experimental approaches used to measure the midpoint potential of metal cofactors. For cofactors in proteins, the midpoint potential not only depends upon the specific chemical characteristics of cofactors but also upon interactions with the surrounding protein, such as the nature of the coordinating ligands and protein environment. These interactions can be tailored to optimize an oxidation/reduction reaction carried out by the protein. As examples, the midpoint potentials of hemes in cytochromes, bacteriochlorophylls in reaction centers, and the manganese cluster of photosystem II are discussed with an emphasis on the influence that protein interactions have on these potentials. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.
Topics: Metalloproteins; Models, Molecular; Oxidation-Reduction; Water
PubMed: 23466333
DOI: 10.1016/j.bbabio.2013.02.014 -
Chemical & Pharmaceutical Bulletin 2024The first enantioselective total synthesis of kopsiyunnanine B, which has a unique folded and complex pentacyclic structure containing six contiguous chiral centers, has...
The first enantioselective total synthesis of kopsiyunnanine B, which has a unique folded and complex pentacyclic structure containing six contiguous chiral centers, has been achieved along our originally proposed biosynthetic pathway. The key reaction of this synthesis includes a bioinspired cascade that builds three ring structures and three chiral centers in one step and features the stereoselective reduction of a β-acrylate and oxidation to an oxindole.
Topics: Stereoisomerism; Oxidation-Reduction
PubMed: 38233133
DOI: 10.1248/cpb.c23-00654 -
Molecules (Basel, Switzerland) Oct 2022Electrochemical behaviors of individual carbon fibers coming from carbon felts were investigated using two different redox couples, 1,1'-dimethanolferrocene and...
Electrochemical behaviors of individual carbon fibers coming from carbon felts were investigated using two different redox couples, 1,1'-dimethanolferrocene and potassium ferrocyanide. Electrochemical responses were examined after different oxidation treatments, then simulated and interpreted using the Kissa 1D software and existing models. Our experiments indicate that a crude carbon fiber behaves as an assembly of sites with different electrochemical reactivities. In such case, the Butler-Volmer law is not appropriate to describe the electron transfer kinetics because of the large created overpotential. Oxidation of the fiber erases the effect by increasing the kinetics of the electron transfer probably by a homogenization and increase of the reactivity on all the fiber. Additionally, analysis of the signal shows the large influence of the convection that affects the electrochemical response even at moderate scan rates (typically below 0.1-0.2 V s).
Topics: Carbon; Carbon Fiber; Electron Transport; Microelectrodes; Oxidation-Reduction
PubMed: 36235121
DOI: 10.3390/molecules27196584 -
Oxidative Medicine and Cellular... 2012
Topics: Cells; Diet; Disease; Oxidation-Reduction; Polyphenols
PubMed: 23213346
DOI: 10.1155/2012/583901 -
Oxidative Medicine and Cellular... 2013Accumulation of oxidized nucleic acids causes genomic instability leading to senescence, apoptosis, and tumorigenesis. Phytoagents are known to reduce the risk of cancer... (Review)
Review
Accumulation of oxidized nucleic acids causes genomic instability leading to senescence, apoptosis, and tumorigenesis. Phytoagents are known to reduce the risk of cancer development; whether such effects are through regulating the extent of nucleic acid oxidation remains unclear. Here, we outlined the role of reactive oxygen species in nucleic acid oxidation as a driving force in cancer progression. The consequential relationship between genome instability and cancer progression highlights the importance of modulation of cellular redox level in cancer management. Current epidemiological and experimental evidence demonstrate the effects and modes of action of phytoagents in nucleic acid oxidation and provide rationales for the use of phytoagents as chemopreventive or therapeutic agents. Vitamins and various phytoagents antagonize carcinogen-triggered oxidative stress by scavenging free radicals and/or activating endogenous defence systems such as Nrf2-regulated antioxidant genes or pathways. Moreover, metal ion chelation by phytoagents helps to attenuate oxidative DNA damage caused by transition metal ions. Besides, the prooxidant effects of some phytoagents pose selective cytotoxicity on cancer cells and shed light on a new strategy of cancer therapy. The "double-edged sword" role of phytoagents as redox regulators in nucleic acid oxidation and their possible roles in cancer prevention or therapy are discussed in this review.
Topics: Animals; Humans; Neoplasms; Nucleic Acids; Oxidation-Reduction; Phytochemicals; Phytotherapy; Reactive Oxygen Species
PubMed: 24454991
DOI: 10.1155/2013/925804