Transformation of β-Lactam Antibacterial Agents during Aqueous Ozonation: Reaction Pathways and Quantitative Bioassay of Biologically-Active Oxidation Products

Limonene is the fourth-most abundant monoterpene in the atmosphere, which upon oxidation leads to the formation of secondary organic aerosol (SOA) and thereby influences climate and air quality.In this study, the oxidation of limonene by OH at different atmospherically relevant NO and HO2 levels (NO: 0.1 &#8211; 10 ppb; HO2: 20 ppt) was investigated in simulation experiments in the SAPHIR chamber at Forschungszentrum J&#252;lich. The analysis focuses on comparing measured radical concentrations (RO2, HO2, OH) and OH reactivity (kOH) with modeled values calculated using the Master Chemical Mechanism (MCM) version 3.3.1.At high and medium NO concentrations, RO2 is expected to quickly react with NO. An HO2 radical is produced during the process that can be converted back to an OH radical by another reaction with NO. Consistently, for experiments conducted at medium NO levels (~0.5 ppb, RO2 lifetime ~10 s), simulated RO2, HO2, and OH agree with observations within the measurement uncertainties, if the OH reactivity of oxidation products is correctly described.At lower NO concentrations, the regeneration of HO2 in the RO2 + NO reaction is slow and the reaction of RO2 with HO2 gains importance in forming peroxides. However, simulation results show a large discrepancy between calculated radical concentrations and measurements at low NO levels (<0.1 ppb, RO2 lifetime ~ 100 s). Simulated RO2 concentrations are found to be overestimated by a factor of three; simulated HO2 concentrations are underestimated by 50 %; simulated OH concentrations are underestimated by about 35%, even if kOH is correctly described. This suggests that there could be additional RO2 reaction pathways that regenerate HO2 and OH radicals become important, but they are not taken into account in the MCM model.

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Novel biologically active metallophthalocyanines as promising antioxidant-antibacterial agents: Synthesis, characterization and computational properties

Journal of Molecular Structure ◽

10.1016/j.molstruc.2019.127127 ◽

2020 ◽

Vol 1200 ◽

pp. 127127 ◽

Cited By ~ 7

Author(s):

Armağan Günsel ◽

Abdullah Kobyaoğlu ◽

Ahmet T. Bilgiçli ◽

Burak Tüzün ◽

Büşra Tosun ◽

...

Keyword(s):

Antibacterial Agents ◽

Biologically Active ◽

Computational Properties

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Evidence for roles of radicals in protein oxidation in advanced human atherosclerotic plaque

Biochemical Journal ◽

10.1042/bj3330519 ◽

1998 ◽

Vol 333 (3) ◽

pp. 519-525 ◽

Cited By ~ 175

Author(s):

Shanlin FU ◽

Michael J. DAVIES ◽

Roland STOCKER ◽

Roger T. DEAN

Keyword(s):

Hydroxyl Radical ◽

Protein Modification ◽

Indirect Evidence ◽

Transition Metal Ions ◽

Oxidation Products ◽

Reaction Pathways ◽

Radical Attack ◽

Radical Damage ◽

Human Carotid

Oxidative damage might be important in atherogenesis. Oxidized lipids are present at significant concentrations in advanced human plaque, although tissue antioxidants are mostly present at normal concentrations. Indirect evidence of protein modification (notably derivatization of lysine) or oxidation has been obtained by immunochemical methods; the specificities of these antibodies are unclear. Here we present chemical determinations of six protein-bound oxidation products: dopa, o-tyrosine, m-tyrosine, dityrosine, hydroxyleucine and hydroxyvaline, some of which reflect particularly oxy-radical-mediated reaction pathways, which seem to involve mainly the participation of transition- metal ions. We compared the relative abundance of these oxidation products in normal intima, and in human carotid plaque samples with that observed after radiolytically generated hydroxyl radical attack on BSA in vitro. The close similarities in relative abundances in the latter two circumstances indicate that hydroxyl radical damage might occur in plaque. The relatively higher level of dityrosine in plaque than that observed after radiolysis suggests the additional involvement of HOCl-mediated reactions in advanced plaque.

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Oxygenated products formed from OH-initiated reactions of trimethylbenzene: Autoxidation and accretion

10.5194/acp-2020-165 ◽

2020 ◽

Cited By ~ 1

Author(s):

Yuwei Wang ◽

Archit Mehra ◽

Jordan E. Krechmer ◽

Gan Yang ◽

Xiaoyu Hu ◽

...

Keyword(s):

Organic Compounds ◽

Mass Spectrometer ◽

Chemical Ionization ◽

Flow Reactor ◽

Time Of Flight ◽

Oxidation Products ◽

Urban Atmosphere ◽

Reaction Pathways ◽

Peroxy Radicals ◽

Flight Mass Spectrometer

Abstract. Gas-phase oxidation pathways and products of anthropogenic volatile organic compounds (VOCs), mainly aromatics, are the subject of intensive research with attention paid to their contributions to secondary organic aerosol (SOA) formation and potentially, new particle formation (NPF) in the urban atmosphere. In this study, a series of OH-initiated oxidation experiments of trimethylbenzene (TMB, C9H12) including 1,2,4-TMB, 1,3,5-TMB, 1,2,3-TMB, and 1,2,4-(methyl-D3)-TMBs (C9H9D3) were investigated in an oxidation flow reactor (OFR), in the absence and presence of NOx. Products were measured using a suite of state-of-the-art instruments, i.e., a nitrate-based chemical ionization – atmospheric pressure interface time-of-flight mass spectrometer (Nitrate CI-APi-TOF), an iodide-adduct chemical ionization – time-of-flight mass spectrometer (Iodide CI-TOF) equipped with a Filter Inlet for Gases and AEROsols (FIGAERO), and a Vocus proton-transfer-reaction mass spectrometer (Vocus PTR). A large number of C9 products with 1–11 oxygen atoms and C18 products presumably formed from dimerization of C9 peroxy radicals were observed, hinting the extensive existence of autoxidation and accretion reaction pathways in the OH-initiated oxidation reactions of TMBs. Oxidation products of 1,2,4-(methyl-D3)-TMBs with deuterium atoms in different methyl substituents were then used as a molecular basis to propose potential autoxidation reaction pathways. Accretion of C9 peroxy radicals is the most significant for aromatics with meta-substituents and the least for aromatics with ortho-substituents, if the number and size of substituted groups are identical. The presence of NOx would suppress the formation of C18 highly oxygenated molecules (HOMs) and enhance the formation of organonitrates, and even dinitrate organic compounds. Our results show that the oxidation products of TMB are much more diverse and could be more oxygenated than the current mechanisms predict.

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Effect of plant extract against opportunist human pathogen soil bacteria

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/46/2415 ◽

2012 ◽

pp. 89-93

Author(s):

Csaba Tamás Tóth ◽

Mária Csubák

Keyword(s):

Public Health ◽

Biological Activity ◽

Soil Bacteria ◽

Laboratory Tests ◽

Pathogenic Bacteria ◽

Antibacterial Agents ◽

Ambrosia Artemisiifolia ◽

Biologically Active ◽

Human Pathogen ◽

Active Components

Our experiments have repeatedly shown that the extract of ragweed (Ambrosia artemisiifolia) is an antifungal and antibacterial component.In our paper we tested of the biological activity of the herbal substance against opportunistic human pathogenic bacteria strains (Staphylococcusaureus 110003 and 25923; Staphylococcus saprophyticus 110008). Our laboratory tests show that the extract is bacteriostatic and in several cases bactericid. We can assume that from the the agricultural and public health aspects can be extremely dangerous weed, contains biologically active components and it may be suitable for the prepare of antibacterial agents.

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Positive Health Effects of Olive Oil

European Journal of Nutrition & Food Safety ◽

10.9734/ejnfs/2021/v13i630426 ◽

2021 ◽

pp. 1-10

Author(s):

Diana Petričević ◽

Damir Velimirović ◽

Tonči Drlje Drlje

Keyword(s):

Olive Oil ◽

Health Effects ◽

Unsaturated Fatty Acids ◽

Natural Antioxidants ◽

Biologically Active ◽

Oxidation Products ◽

Mediterranean Country ◽

Positive Health ◽

Anticancer Properties ◽

Phenolic Components

Olive oil is the main source of fat in the Mediterranean diet. Although the use of olive oil has a long history, in recent decades it has experienced a full bloom all over the world. The consumption of olive oil in Croatia, as a Mediterranean country, is modest (2L per capita). This paper discusses basic characteristics of olive oil, with special emphasis on its health effects. Olive oil is rich in chlorophyll, carotenoids, and vitamin E, all of which serve as natural antioxidants, whereas its phenolic components, oleuropein and hydroxytyrosol, impact health positively in several ways. In addition to being powerful antioxidants, phenols in olive oil have anti-inflammatory, antiangiogenic, and anticancer properties. They modulate the immune system by affecting white blood cell proliferation and producing cytokine. The oil’s anticancer properties are of particular importance. Mono-unsaturated fatty acids raise the level of “good cholesterol,” thus preventing the atherosclerosis process. Oleic acid in olive oil is less sensitive to oxidation, which is why it reduces the risk of harmful oxidation products. It has a high biological value and is easily digestible. Its antioxidant components slow down the ageing process and prevent the formation of cancer cells by neutralizing free radicals. It is important to preserve as many biologically active substances of olive oil as possible by properly storing and preparing the oil in order to maximize its effectiveness.

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Oxygenated products formed from OH-initiated reactions of trimethylbenzene: autoxidation and accretion

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-9563-2020 ◽

2020 ◽

Vol 20 (15) ◽

pp. 9563-9579

Author(s):

Yuwei Wang ◽

Archit Mehra ◽

Jordan E. Krechmer ◽

Gan Yang ◽

Xiaoyu Hu ◽

...

Keyword(s):

Organic Compounds ◽

Mass Spectrometer ◽

Chemical Ionization ◽

Flow Reactor ◽

Time Of Flight ◽

Oxidation Products ◽

Urban Atmosphere ◽

Reaction Pathways ◽

Peroxy Radicals ◽

Flight Mass Spectrometer

Abstract. Gas-phase oxidation pathways and products of anthropogenic volatile organic compounds (VOCs), mainly aromatics, are the subject of intensive research, with attention paid to their contributions to secondary organic aerosol (SOA) formation and potentially new particle formation (NPF) in the urban atmosphere. In this study, a series of OH-initiated oxidation experiments of trimethylbenzene (TMB, C9H12) including 1,2,4-TMB, 1,3,5-TMB, 1,2,3-TMB, and 1,2,4-(methyl-D3)-TMBs (C9H9D3) were investigated in an oxidation flow reactor (OFR) in the absence and presence of NOx. Products were measured using a suite of state-of-the-art instruments, i.e. a nitrate-based chemical ionization–atmospheric pressure interface time-of-flight mass spectrometer (nitrate CI-APi-TOF), an iodide-adduct chemical ionization time-of-flight mass spectrometer (iodide CI-TOF) equipped with a Filter Inlet for Gases and AEROsols (FIGAERO), and a Vocus proton-transfer-reaction mass spectrometer (Vocus PTR). A large number of C9 products with 1–11 oxygen atoms and C18 products presumably formed from dimerization of C9 peroxy radicals were observed, hinting at the extensive existence of autoxidation and accretion reaction pathways in the OH-initiated oxidation reactions of TMBs. Oxidation products of 1,2,4-(methyl-D3)-TMBs with deuterium atoms in different methyl substituents were then used as a molecular basis to propose potential autoxidation reaction pathways. Accretion of C9 peroxy radicals is the most significant for aromatics with meta-substituents and the least for aromatics with ortho-substituents if the number and size of substituted groups are identical. The presence of NOx would suppress the formation of highly oxygenated molecules (HOMs) of C18 and enhance the formation of organonitrates and even dinitrate organic compounds. Our results show that the oxidation products of TMB are much more diverse and could be more oxygenated than the current mechanisms predict.

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Building BORIS – an outreach project on drug design and molecular modelling

The Biochemist ◽

10.1042/bio03902050 ◽

2017 ◽

Vol 39 (2) ◽

pp. 50-51

Author(s):

Steven Rossington

Keyword(s):

Organic Chemistry ◽

Molecular Modelling ◽

Biological Effect ◽

The Body ◽

Biologically Active ◽

Reaction Pathways ◽

Cellular Activity ◽

Chemical Product ◽

Anti Cancer ◽

The University

Within university chemistry departments, organic chemists are formulating reaction pathways which will yield a desired chemical product. In most cases, it is often found that the targeted product exerts some beneficial biological effect towards cellular activity. In my organic chemistry lectureship within the University of Salford, I too am involved in the synthesis of potential biologically active compounds; namely a range of anti-cancer compounds and anti-bacterial agents. Using my professional knowledge, I have developed an outreach project known as BORIS designed to show GCSE and A-level students what proteins look like, their importance and role within the body and how drugs interact with them.

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Guanine Oxidation in Double-stranded DNA by MnTMPyP/KHSO5: At Least Three Independent Reaction Pathways

Metal-Based Drugs ◽

10.1155/mbd.2001.47 ◽

2001 ◽

Vol 8 (1) ◽

pp. 47-56 ◽

Cited By ~ 14

Author(s):

Andrea Lapi ◽

Geneviève Pratviel ◽

Bernard Meunier

Keyword(s):

Degradation Products ◽

Oxidation Products ◽

Spiro Compound ◽

Reaction Pathways ◽

Guanine Oxidation ◽

Double Stranded Dna ◽

Independent Reaction ◽

Reaction Routes ◽

Damaged Dna

In order to better define the mechanism and the products of guanine oxidation within DNA, we investigated the details of the mechanism of guanine oxidation by a metalloporphyrin, Mn-TMPyP, associated to KHSO5 on oligonucleotides. We found that the three major products of guanine oxidation are formed by independent reaction routes. The oxidized guanidinohydantoin (1) and the proposed spiro compound 3 derivatives are not precursors of imidazolone lesion (Iz). These guanine lesions as well as their degradation products, may account for non-detected guanine oxidation products on oxidatively damaged DNA.

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