1
|
Duché G, Sanderson JM. The Chemical Reactivity of Membrane Lipids. Chem Rev 2024; 124:3284-3330. [PMID: 38498932 PMCID: PMC10979411 DOI: 10.1021/acs.chemrev.3c00608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 03/20/2024]
Abstract
It is well-known that aqueous dispersions of phospholipids spontaneously assemble into bilayer structures. These structures have numerous applications across chemistry and materials science and form the fundamental structural unit of the biological membrane. The particular environment of the lipid bilayer, with a water-poor low dielectric core surrounded by a more polar and better hydrated interfacial region, gives the membrane particular biophysical and physicochemical properties and presents a unique environment for chemical reactions to occur. Many different types of molecule spanning a range of sizes, from dissolved gases through small organics to proteins, are able to interact with membranes and promote chemical changes to lipids that subsequently affect the physicochemical properties of the bilayer. This Review describes the chemical reactivity exhibited by lipids in their membrane form, with an emphasis on conditions where the lipids are well hydrated in the form of bilayers. Key topics include the following: lytic reactions of glyceryl esters, including hydrolysis, aminolysis, and transesterification; oxidation reactions of alkenes in unsaturated fatty acids and sterols, including autoxidation and oxidation by singlet oxygen; reactivity of headgroups, particularly with reactive carbonyl species; and E/Z isomerization of alkenes. The consequences of reactivity for biological activity and biophysical properties are also discussed.
Collapse
Affiliation(s)
- Genevieve Duché
- Génie
Enzimatique et Cellulaire, Université
Technologique de Compiègne, Compiègne 60200, France
| | - John M Sanderson
- Chemistry
Department, Durham University, Durham DH1 3LE, United Kingdom
| |
Collapse
|
2
|
Shashni B, Tamaoki J, Kobayashi M, Nagasaki Y. Design of a new self-assembling antioxidant nanomedicine to ameliorate oxidative stress in zebrafish embryos. Acta Biomater 2023; 159:367-381. [PMID: 36640953 DOI: 10.1016/j.actbio.2023.01.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 12/21/2022] [Accepted: 01/05/2023] [Indexed: 01/13/2023]
Abstract
Oxidative stress, which is a persistent state of elevated reactive oxygen species (ROS), is implicated in the pathogeneses of several diseases, making antioxidant-based therapeutics the aptest intervention. Nevertheless, the clinical failure of conventional low-molecular-weight (LMW) antioxidants in oxidative stress-related diseases to yield favorable therapeutic outcomes and an increased mortality rate attributable to their poor pharmacokinetic characteristics, necessitates the development of alternative therapeutics. In light of this, we designed and synthesized a new amphiphilic polymer functionalized with a clinically safe base polymer of poly(styrene-co-maleic anhydride) copolymer conjugated with the LMW pleiotropic antioxidant TEMPO (a potent antioxidant) and biocompatible poly(ethylene glycol) (TEMPO-installed PSMA-g-PEG), which self-assembles into nano-sized micelles (SMAPoTN) under physiological conditions. We investigated its safety and antioxidant ability using zebrafish models. Common LMW antioxidants, such as 4-hydroxy-TEMPO (TEMPOL), vitamin C, N-acetyl-L-cysteine, and edaravone exposure induced phenotypic distortions, a manifestation of developmental toxicity, and resulted in high lethality in zebrafish larvae. LMW TEMPOL also adversely affected embryo hatchability, induced arrhythmia and cardiac edema, and failed to protect against oxidative stress. In contrast, exposure of zebrafish embryos to SMAPoTN increased the hatchability, protected embryos against various inducers of oxidative stress, and did not induce any phenotypic alterations or discernible toxicity. Taken together, we conclude that SMAPoTN surpasses LMW TEMPOL in terms of the ability to protect zebrafish, attributable to efficient ROS scavenging without perturbing normal redox homeostasis. These results imply that SMAPoTN can be used as a therapeutic intervention against various oxidative stress-induced diseases. STATEMENT OF SIGNIFICANCE: Failure of low molecular weight (LMW) antioxidants to improve therapeutic index in various oxidative stress-related pathogenesis, attributable to their poor pharmacokinetic characteristics, greatly limits their clinical translation. To overcome this limitation, we developed a self-assembling antioxidant nanoparticle (SMAPoTN) comprised of amphiphilic polymer; poly(styrene-co-maleic anhydride) conjugated with TEMPO as an antioxidant and biocompatible poly(ethylene glycol). Preliminary studies carried out in the in vivo models of zebrafish embryos confirmed that exposure of LMW antioxidant resulted in acute developmental toxicity, high lethality, and failure to rescue embryos against oxidative stress inducers. In contrast, SMAPoTN did not exert discernible toxicity and significantly improved their survival under oxidative stress. Our finding establishes antioxidant nanoparticles as more suitable therapeutic intervention for oxidative stress-induced diseases than LMW antioxidants.
Collapse
Affiliation(s)
- Babita Shashni
- Faculty of Pure and Applied Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8573, Japan
| | - Junya Tamaoki
- Faculty of Medicine, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8575, Japan
| | - Makoto Kobayashi
- Faculty of Medicine, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8575, Japan
| | - Yukio Nagasaki
- Faculty of Pure and Applied Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8573, Japan; Master's Program in Medical Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8573, Japan; Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8573, Japan.
| |
Collapse
|
3
|
Fan KK, Zhou YM, Wei Y, Han RM, Wang P, Skibsted LH, Zhang JP. Peroxyl radical induced membrane instability of giant unilamellar vesicles and anti-lipooxidation protection. Biophys Chem 2022; 285:106807. [DOI: 10.1016/j.bpc.2022.106807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/07/2022] [Accepted: 03/20/2022] [Indexed: 11/02/2022]
|
4
|
Hedayati HR, Khorasani M, Ahmadi M, Ballard N. Preparation of well-defined Poly(Vinyl alcohol) by hydrolysis of Poly(Vinyl acetate) synthesized by RAFT suspension polymerization. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.124674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
5
|
Lin KH, Lin WC, Liu SH, Shu CM. Evaluation of thermal reaction for two azo compounds by using 20-L apparatus and calorimetry. J Loss Prev Process Ind 2021. [DOI: 10.1016/j.jlp.2021.104587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
6
|
Niki E. Commentary on "Azocompounds as generators of defined radical species: Contributions and challenges for free radical research" by López-Alarcón et al. [Free Radic. Biol. Med. 160 (2020) 78-91]. Free Radic Biol Med 2021; 164:96-98. [PMID: 33412271 DOI: 10.1016/j.freeradbiomed.2020.12.446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/26/2020] [Accepted: 12/29/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Etsuo Niki
- Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo, 153-8904, Japan.
| |
Collapse
|
7
|
MitoCLox: A Novel Mitochondria-Targeted Fluorescent Probe for Tracing Lipid Peroxidation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:9710208. [PMID: 31827716 PMCID: PMC6885286 DOI: 10.1155/2019/9710208] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 09/12/2019] [Indexed: 02/06/2023]
Abstract
Peroxidation of cardiolipin (CL) in the inner mitochondrial membrane plays a key role in the development of various pathologies and, probably, aging. The four fatty acid tails of CL are usually polyunsaturated, which makes CL particularly sensitive to peroxidation. Peroxidation of CL is involved in the initiation of apoptosis, as well as in some other important cellular signaling chains. However, the studies of CL peroxidation are strongly limited by the lack of methods for its tracing in living cells. We have synthesized a new mitochondria-targeted fluorescent probe sensitive to lipid peroxidation (dubbed MitoCLox), where the BODIPY fluorophore, carrying a diene-containing moiety (as in the C11-BODIPY (581/591) probe), is conjugated with a triphenylphosphonium cation (TPP+) via a long flexible linker that contains two amide bonds. The oxidation of MitoCLox could be measured either as a decrease of absorbance at 588 nm or as an increase of fluorescence in the ratiometric mode at 520/590 nm (emission). In CL-containing liposomes, MitoCLox oxidation was induced by cytochrome c and developed in parallel with cardiolipin oxidation. TPP+-based mitochondria-targeted antioxidant SkQ1, in its reduced form, inhibited oxidation of MitoCLox concurrently with the peroxidation of cardiolipin. Molecular dynamic simulations of MitoCLox in a cardiolipin-containing membrane showed affinity of positively charged MitoCLox to negatively charged CL molecules; the oxidizable diene moiety of MitoCLox resided on the same depth as the cardiolipin lipid peroxides. We suggest that MitoCLox could be used for monitoring CL oxidation in vivo and, owing to its flexible linker, also serve as a platform for producing peroxidation sensors with affinity to particular lipids.
Collapse
|
8
|
Shah R, Farmer LA, Zilka O, Van Kessel ATM, Pratt DA. Beyond DPPH: Use of Fluorescence-Enabled Inhibited Autoxidation to Predict Oxidative Cell Death Rescue. Cell Chem Biol 2019; 26:1594-1607.e7. [PMID: 31564533 DOI: 10.1016/j.chembiol.2019.09.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/21/2019] [Accepted: 09/09/2019] [Indexed: 02/07/2023]
Abstract
"Antioxidant activity" is an often invoked, but generally poorly characterized, molecular property. Several assays are available to determine antioxidant activity, the most popular of which is based upon the ability of a putative antioxidant to reduce 2,2-diphenyl-1-picrylhydrazyl. Here, we show that the results of this assay do not correlate with the potency of putative antioxidants as inhibitors of ferroptosis, the oxidative cell death modality associated with (phospho)lipid peroxidation. We subsequently describe our efforts to develop an approach that quantifies the reactivity of putative antioxidants with the (phospho)lipid peroxyl radicals that propagate (phospho)lipid peroxidation (dubbed FENIX [fluorescence-enabled inhibited autoxidation]). The results obtained with FENIX afford an excellent correlation with anti-ferroptotic potency, which facilitates mechanistic characterization of ferroptosis inhibitors, and reveals the importance of H-bonding interactions between antioxidant and phospholipid that underlie both the lackluster antioxidant activity of phenols under physiologically relevant conditions and the emergence of arylamines as inhibitors of choice.
Collapse
Affiliation(s)
- Ron Shah
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Luke A Farmer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Omkar Zilka
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Antonius T M Van Kessel
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Derek A Pratt
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
| |
Collapse
|
9
|
Waris S, Habib S, Khan S, Kausar T, Naeem SM, Siddiqui SA, Moinuddin, Ali A. Molecular docking explores heightened immunogenicity and structural dynamics of acetaldehyde human immunoglobulin G adduct. IUBMB Life 2019; 71:1522-1536. [PMID: 31185142 DOI: 10.1002/iub.2078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 05/08/2019] [Indexed: 12/19/2022]
Abstract
Acetaldehyde is a metabolite of ethanol, an important constituent of tobacco pyrolysis and the aldehydic product of lipid peroxidation. Acetaldehyde induced toxicity is mainly due to its binding to cellular macromolecules resulting in the formation of stable adducts accompanied by oxidative stress. The aim of this study was to characterize structural and immunological alterations in human immunoglobulin G (IgG) modified with acetaldehyde in the presence of sodium borohydride, a reducing agent. The IgG modifications were studied by various physicochemical techniques such as fluorescence and CD spectroscopy, free amino group estimation, 2,2-azobis 2-amidinopropane (AAPH) induced red blood cell hemolysis as well as transmission electron microscopy. Molecular docking was also employed to predict the preferential binding of acetaldehyde to IgG. The immunogenicity of native and acetaldehyde-modified IgG was investigated by immunizing female New Zealand white rabbits using native and modified IgG as antigens. Binding specificity and cross reactivity of rabbit antibodies was screened by competitive inhibition ELISA and band shift assays. The modification of human IgG with acetaldehyde results in quenching of the fluorescence of tyrosine residues, decrease in free amino group content, a change in the antioxidant property as well as formation of cross-linked structures in human IgG. Molecular docking reveals strong binding of IgG to acetaldehyde. Moreover, acetaldehyde modified IgG induced high titer antibodies (>1:12800) in the experimental animals. The antibodies exhibited high specificity in competitive binding assay toward acetaldehyde modified human IgG. The results indicate that acetaldehyde induces alterations in secondary and tertiary structure of IgG molecule that leads to formation of neo-epitopes on IgG that enhances its immunogenicity.
Collapse
Affiliation(s)
- Sana Waris
- Department of Biochemistry, Faculty of Medicine, J. N. Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Safia Habib
- Department of Biochemistry, Faculty of Medicine, J. N. Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Shifa Khan
- Department of Biochemistry, Faculty of Medicine, J. N. Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Tasneem Kausar
- Department of Chemistry, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Shahid M Naeem
- Department of Chemistry, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Shahid A Siddiqui
- Department of Radiotherapy, Faculty of Medicine, J. N. Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Moinuddin
- Department of Biochemistry, Faculty of Medicine, J. N. Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Asif Ali
- Department of Biochemistry, Faculty of Medicine, J. N. Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| |
Collapse
|
10
|
A novel antioxidant sulfated polysaccharide from the algae Gracilaria caudata: In vitro and in vivo activities. Food Hydrocoll 2019. [DOI: 10.1016/j.foodhyd.2018.12.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
11
|
Chlorogenic acid isomers directly interact with Keap 1-Nrf2 signaling in Caco-2 cells. Mol Cell Biochem 2019; 457:105-118. [PMID: 30895499 PMCID: PMC6548765 DOI: 10.1007/s11010-019-03516-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 03/08/2019] [Indexed: 11/29/2022]
Abstract
Chlorogenic acid (CGA) exists as multiple isomers (e.g., 3-CQA, 4-CQA, 5-CQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA) in foods such as coffee beverages, fruits and vegetables. This study aimed to investigate relative activities of these six different CGA isomers to modify redox biology in inflamed Caco-2 cells that involved Nrf2 signaling. Caco-2 cells were pre-treated with individual CGA isomers to assess the relative effectiveness to mitigate oxidative stress. Isomer-specific capacity of different CGA isomers for direct free radical scavenging activity and potential endogenous control of oxidative stress were determined using chemical assays and cell-based experiments, respectively. Molecular dynamics simulations of the CGA and Keap1-Nrf2 complex were performed to predict CGA structure-specific interactions. Results demonstrated that dicaffeoylquinic acid (diCQA including 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA) isomers had greater (p < 0.05) affinity to ameliorate oxidative stress through direct free radical scavenging activity. This observation corresponded to greater (p < 0.05) capacity to activate Nrf2 signaling compared to caffeoylquinic acid (CQA including 3-CQA, 4-CQA, and 5-CQA) isomers in inflamed differentiated Caco-2 cells. Simulations revealed that differences between the ability of CQA and diCQA to interact with the Keap1-Nrf2 complex may be due to differences in relative orientation within this complex. The observed CGA isomer-specific affinity for CQA to activate Nrf2 signaling was confirmed by nuclear translocation of Nrf2 induced by CGA and greater (p < 0.05) upregulation of genes related to Nrf2 expression.
Collapse
|
12
|
Taute H, Bester MJ, Gaspar ARM. The dual functionality of antimicrobial peptides Os and Os-C in human leukocytes. J Pept Sci 2019; 25:e3156. [PMID: 30740816 DOI: 10.1002/psc.3156] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 01/11/2019] [Accepted: 01/22/2019] [Indexed: 12/22/2022]
Abstract
Antimicrobial peptides (AMPs), Os and Os-C, have been identified as multifunctional peptides with antibacterial, antiendotoxin, and anti-inflammatory properties. For further development of Os and Os-C as therapeutic peptides, it is essential to evaluate these effects in human mononuclear (MN) and polymorphonuclear (PMN) leukocytes. The cytotoxicity and the effects of both peptides on MN and PMN morphology were determined with the Alamar-Blue assay and scanning electron microscopy, respectively. The ability of Os and Os-C to induce reactive oxygen species (ROS) and to protect against 2,2'-azobis(2-amidinopropane) dihydrochloride-induced oxidative damage in both cell populations was evaluated using 2',7'-dichlorofluorescin diacetate (DCFH-DA). Using fluorescently labeled peptides, the ability of the peptides to cross the cell membranes of MN and PMN was also evaluated. At the minimum bactericidal concentrations of Os and Os-C, neither peptide was cytotoxic. Os caused morphological features of toxicity at 100 μM, entered MN cells, and also protected these cells against oxidative damage. Os-C caused MN and PMN leukocyte activation associated with ROS formation and was unable to penetrate cell membranes, indicating extracellular membrane interactions. This study confirms that both Os and Os-C at less than 100 μM are not cytotoxic. The MN-specific uptake of Os identifies it as a cell-specific cargo-carrier peptide, with additional anti-inflammatory properties. In contrast, the ability of Os-C to activate MN and PMN cells implies that this peptide should be further evaluated as an AMP, which, in addition to its ability to eradicate infection, can further enhance host immunity. These novel characteristics of Os and Os-C indicate that these AMPs as peptides can be further developed for specific applications.
Collapse
Affiliation(s)
- Helena Taute
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, South Africa
| | - Megan J Bester
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, South Africa
| | - Anabella R M Gaspar
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural Sciences, University of Pretoria, South Africa
| |
Collapse
|
13
|
Zielinski ZAM, Pratt DA. H-Atom Abstraction vs Addition: Accounting for the Diverse Product Distribution in the Autoxidation of Cholesterol and Its Esters. J Am Chem Soc 2019; 141:3037-3051. [DOI: 10.1021/jacs.8b11524] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Zosia A. M. Zielinski
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Derek A. Pratt
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| |
Collapse
|
14
|
Moad G. A Critical Assessment of the Kinetics and Mechanism of Initiation of Radical Polymerization with Commercially Available Dialkyldiazene Initiators. Prog Polym Sci 2019. [DOI: 10.1016/j.progpolymsci.2018.08.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
15
|
Greene LE, Lincoln R, Cosa G. Spatio-temporal monitoring of lipid peroxyl radicals in live cell studies combining fluorogenic antioxidants and fluorescence microscopy methods. Free Radic Biol Med 2018; 128:124-136. [PMID: 29649566 DOI: 10.1016/j.freeradbiomed.2018.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 12/28/2022]
Abstract
Lipid peroxidation of polyunsaturated fatty acids in cells may occur via their catalytic autoxidation through peroxyl radicals under oxidative stress conditions. Lipid peroxidation is related to a number of pathologies, and may be invoked in new forms of regulated cell death, yet it may also have beneficial roles in cell signaling cascades. Antioxidants are a natural line of defense against lipid peroxidation, and may accordingly impact the biological outcome associated with the redox chemistry of lipid peroxidation. Critical to unraveling the physiological and pathological role of lipid peroxidation is the development of novel probes with the partition, chemical sensitivity and more importantly, molecular specificity, enabling the spatial and temporal imaging of peroxyl radicals in the lipid membranes of live cells, reporting on the redox status of the cell membrane. This review describes our recent progress to visualize lipid peroxidation in model membrane systems and in live cell studies. Our work portrays the mechanistic insight leading to the development of a highly sensitive probe to monitor lipid peroxyl radicals (LOO•). It also describes technical aspects including reagents and fluorescence microscopy methodologies to consider in order to achieve the much sought after monitoring of rates of lipid peroxyl radical production in live cell studies, be it under oxidative stress but also under cell homeostasis. This review seeks to bring attention to the study of lipid redox reactions and to lay the groundwork for the adoption of fluorogenic antioxidant probeshancement and maximum intensity recorded in turn provide a benchmark to estimate, when compared to the control BODIPY dye lacking the intramolecular PeT based switch, the overall exte and related fluorescence microscopy methods toward gaining rich spatiotemporal information on lipid peroxidation in live cells.
Collapse
Affiliation(s)
- Lana E Greene
- Department of Chemistry and Quebec Center for Advanced Materials (QCAM/CQMF), McGill University, 801 Sherbrooke Street West, Montreal, QC, Canada H3A 0B8
| | - Richard Lincoln
- Department of Chemistry and Quebec Center for Advanced Materials (QCAM/CQMF), McGill University, 801 Sherbrooke Street West, Montreal, QC, Canada H3A 0B8
| | - Gonzalo Cosa
- Department of Chemistry and Quebec Center for Advanced Materials (QCAM/CQMF), McGill University, 801 Sherbrooke Street West, Montreal, QC, Canada H3A 0B8.
| |
Collapse
|
16
|
Liang N, Kitts DD. Amelioration of Oxidative Stress in Caco-2 Cells Treated with Pro-inflammatory Proteins by Chlorogenic Acid Isomers via Activation of the Nrf2-Keap1-ARE-Signaling Pathway. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:11008-11017. [PMID: 30259744 DOI: 10.1021/acs.jafc.8b03983] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Understanding the potential effects of chlorogenic acid (CGA) isomers on the intestinal epithelium is important because coffee intake exposes consumers to the six major CGA isomers: 3-caffeoylquinic acid (3-CQA), 4-caffeoylquinic acid (4-CQA), 5-caffeoylquinic acid (5-CQA), 3,4-dicaffeoylquinic acid (3,4-diCQA), 3,5-dicaffeoylquinic acid (3,5-diCQA), and 4,5-dicaffeoylquinic acid (4,5-diCQA). The present study determined the relative effects of CGA isomers on the antioxidant status of inflamed Caco-2 intestinal cells by investigating the oxidative-stress-responsive pathway and nuclear-factor-erythroid-derived-2-like 2 (Nrf2) signaling. Differentiated Caco-2 cells were challenged with the inflammatory mediators PMA and IFNγ, as a model of intestinal inflammation in vitro. Significant redox ( p < 0.05) responses to these mediators were assessed by indirect measurement of induced generation of reactive oxygen species (ROS), as well as the expression of reduced (GSH) and oxidized (GSSG) glutathione. This translated to a 40% reduction in the GSH/GSSG ratio. We found that responses in these parameters were associated with increased Nrf2 activation ( p < 0.05). ROS generation and increased IL-8 secretion were found in challenged cells, indicating an association between induced oxidation and inflammatory status. Oxidative stress was ameliorated by CGA isomers, which scavenged intracellular ROS, increased GSH, and activated Nrf2 signaling. diCQA isomers were relatively more effective at reducing IL-8 ( p < 0.05). The observed increase in Nrf2 signaling led to upregulated expression of some Nrf2 target genes ( GPX2, KEAP1, and NFE2L2) in Caco-2 cells and activated the Nrf2-Keap1-ARE-signaling pathway. These findings indicate that CGA isomers present in coffee have bioactivity toward alleviating oxidative stress associated with intestinal inflammation.
Collapse
Affiliation(s)
- Ningjian Liang
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems , The University of British Columbia , 2205 East Mall , Vancouver , British Columbia V6T 1Z4 , Canada
| | - David D Kitts
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems , The University of British Columbia , 2205 East Mall , Vancouver , British Columbia V6T 1Z4 , Canada
| |
Collapse
|
17
|
Alam MB, Bajpai VK, Lee J, Zhao P, Byeon JH, Ra JS, Majumder R, Lee JS, Yoon JI, Rather IA, Park YH, Kim K, Na M, Lee SH. Inhibition of melanogenesis by jineol from Scolopendra subspinipes mutilans via MAP-Kinase mediated MITF downregulation and the proteasomal degradation of tyrosinase. Sci Rep 2017; 7:45858. [PMID: 28393917 PMCID: PMC5385534 DOI: 10.1038/srep45858] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/06/2017] [Indexed: 12/26/2022] Open
Abstract
In this study, the authors investigated the anti-melanogenic effects of 3,8-dihydroxyquinoline (jineol) isolated from Scolopendra subspinipes mutilans, the mechanisms responsible for its inhibition of melanogenesis in melan-a cells, and its antioxidant efficacy. Mushroom tyrosinase activities and melanin contents were determined in melan-a cells, and the protein and mRNA levels of MITF, tyrosinase, TYRP-1, and TYRP-2 were assessed. Jineol exhibited significant, concentration-dependent antioxidant effects as determined by DPPH, ABTS, CUPRAC, and FRAP assays. Jineol significantly inhibited mushroom tyrosinase activity by functioning as an uncompetitive inhibitor, and markedly inhibited melanin production and intracellular tyrosinase activity in melan-a cells. In addition, jineol abolished the expressions of tyrosinase, TYRP-1, TYRP-2, and MITF, thereby blocking melanin production and interfering with the phosphorylations of ERK1/2 and p38. Furthermore, specific inhibitors of ERK1/2 and p38 prevented melanogenesis inhibition by jineol, and the proteasome inhibitor (MG-132) prevented jineol-induced reductions in cellular tyrosinase levels. Taken together, jineol was found to stimulate MAP-kinase (ERK1/2 and p38) phosphorylation and the proteolytic degradation pathway, which led to the degradations of MITF and tyrosinase, and to suppress the productions of melanin.
Collapse
Affiliation(s)
- Md Badrul Alam
- Department of Food Science and Biotechnology, Graduate School, Kyungpook National University, Daegu 41566, Korea
| | - Vivek K Bajpai
- Department of Applied Microbiology and Biotechnology, Microbiome Laboratory, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Korea
| | - JungIn Lee
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea
| | - Peijun Zhao
- Department of Food Science and Biotechnology, Graduate School, Kyungpook National University, Daegu 41566, Korea
| | - Jung-Hee Byeon
- Department of Food Science and Biotechnology, Graduate School, Kyungpook National University, Daegu 41566, Korea
| | - Jeong-Sic Ra
- Department of Food Science and Biotechnology, Graduate School, Kyungpook National University, Daegu 41566, Korea
| | - Rajib Majumder
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.,Bio-security and Food Safety, NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute (EMAI), Menangle, NSW 2567, Australia
| | - Jong Sung Lee
- Kcellbio, Seoulsoop Kolon Digital Tower, Seongsuil-ro-4-gil, Seongdong-gu 04713, Seoul, Korea
| | - Jung-In Yoon
- Kcellbio, Seoulsoop Kolon Digital Tower, Seongsuil-ro-4-gil, Seongdong-gu 04713, Seoul, Korea
| | - Irfan A Rather
- Department of Applied Microbiology and Biotechnology, Microbiome Laboratory, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Korea
| | - Yong-Ha Park
- Department of Applied Microbiology and Biotechnology, Microbiome Laboratory, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Korea
| | - Kangmin Kim
- Division of Biotechnology, College of Environmental and Bioresource Sciences, Chonbuk National University, 79 Gobong-ro, Iksan-si 570-752, Jeonbuk, Republic of Korea
| | - MinKyun Na
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea
| | - Sang-Han Lee
- Department of Food Science and Biotechnology, Graduate School, Kyungpook National University, Daegu 41566, Korea
| |
Collapse
|
18
|
Antioxidant efficacy and the upregulation of Nrf2-mediated HO-1 expression by (+)-lariciresinol, a lignan isolated from Rubia philippinensis, through the activation of p38. Sci Rep 2017; 7:46035. [PMID: 28378774 PMCID: PMC5380954 DOI: 10.1038/srep46035] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/08/2017] [Indexed: 12/17/2022] Open
Abstract
The aim of the present study was to examine the antioxidative activity of (+)-lariciresinol (LRSL), an optically active lignan isolated from Rubia philippinensis in several in vitro assays. LRSL was also subjected to evaluate its inhibitory effect against the generation of reactive oxygen species (ROS) in murine macrophage (RAW 264.7) cells. The results showed that LRSL possessed very strong radical scavenging activity and reducing power, as well as inhibited ROS generation in a dose-dependent manner without showing any cytotoxicity. The transcriptional and translational levels of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) were markedly higher in the sample treated group. LRSL treatment also increased the transcriptional and translational activities of NF-E2-related factor-2 (Nrf-2) with a corresponding increase in the transcriptional and translational activities of the heme oxygenase-1 (HO-1). LRSL activated p38 and treatments with SB239063 (a p38 inhibitor) suppressed the LRSL-induced activation of Nrf2, resulting in a decrease in HO-1 expression. Collectively, the data demonstrated that LRSL has potent antioxidative activity, decreasing ROS generation in RAW 264.7 cells and increasing the transcriptional and translational levels of antioxidant enzymes by activating Nrf2-mediated HO-1 induction via p38 signaling.
Collapse
|
19
|
Alam MB, Kwon KR, Lee SH, Lee SH. Lannea coromandelica (Houtt.) Merr. Induces Heme Oxygenase 1 (HO-1) Expression and Reduces Oxidative Stress via the p38/c-Jun N-Terminal Kinase-Nuclear Factor Erythroid 2-Related Factor 2 (p38/JNK-NRF2)-Mediated Antioxidant Pathway. Int J Mol Sci 2017; 18:ijms18020266. [PMID: 28146074 PMCID: PMC5343802 DOI: 10.3390/ijms18020266] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 01/22/2017] [Accepted: 01/23/2017] [Indexed: 01/25/2023] Open
Abstract
The leaves of Lannea coromandelica (Houtt.) Merr. are used in the Garo, Pahan, and Teli tribal communities of Bangladesh as a traditional medicinal plant to treat hepatitis, diabetes, ulcers, heart disease, and dysentery. However, there have been limited phytochemical and biological studies on the bark of L. coromandelica. This study aimed to investigate the antioxidant activities of L. coromandelica bark extract (LCBE) and the underlying mechanism using RAW 264.7 cells. The LCBE was analysed by high-pressure liquid chromatography (HPLC) to detect its key polyphenolic compounds. Various in vitro antioxidant assays were performed using RAW 264.7 cells to assess the antioxidant effects of the LCBE and to understand the underlying molecular mechanism. HPLC revealed the presence of gallic acid, (−)-epigallocatechin-3-gallate, catechin, chlorogenic acid, and caffeic acid in the LCBE. The extract showed a very potent capacity to scavenge numerous free radicals through hydrogen atom transfer and/or electron donation and also quenched cellular reactive oxygen species (ROS) generation without showing any toxicity. The LCBE was found to combat the oxidative stress by enhancing the expression, at both transcriptional and translational levels, of primary antioxidant enzymes as well as phase II detoxifying enzymes, especially heme oxygenase 1, through the upregulation of the nuclear factor erythroid 2-related factor 2 (NRF2)-mediated pathway in RAW 264.7 cells via the phosphorylation of p38 kinase and c-Jun N-terminal kinase (JNK). The LCBE exhibited strong antioxidant activities and mitigated the cellular ROS production. These results provide scientific evidence of its potential as an ideal applicant for a cost-effective, readily available, and natural phytochemical, as well as a strategy for preventing diseases associated with oxidative stress and attenuating disease progress.
Collapse
Affiliation(s)
- Md Badrul Alam
- Department of Food Science and Biotechnology, Graduate School, Kyungpook National University, Daegu 41566, Korea.
| | - Kyoo-Ri Kwon
- Department of Food Science and Biotechnology, Graduate School, Kyungpook National University, Daegu 41566, Korea.
| | - Seok-Hyun Lee
- Department of Food Science and Biotechnology, Graduate School, Kyungpook National University, Daegu 41566, Korea.
| | - Sang-Han Lee
- Department of Food Science and Biotechnology, Graduate School, Kyungpook National University, Daegu 41566, Korea.
- Food and Bio-Industry Research Institute, Kyungpook National University, Daegu 41566, Korea.
| |
Collapse
|
20
|
Alam MB, Seo BJ, Zhao P, Lee SH. Anti-Melanogenic Activities of Heracleum moellendorffii via ERK1/2-Mediated MITF Downregulation. Int J Mol Sci 2016; 17:ijms17111844. [PMID: 27827938 PMCID: PMC5133844 DOI: 10.3390/ijms17111844] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/27/2016] [Accepted: 10/31/2016] [Indexed: 11/26/2022] Open
Abstract
In this study, the anti-melanogenic effects of Heracleum moellendorffii Hance extract (HmHe) and the mechanisms through which it inhibits melanogenesis in melan-a cells were investigated. Mushroom tyrosinase (TYR) activity and melanin content as well as cellular tyrosinase activity were measured in the cells. mRNA and protein expression of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), TYR-related protein-1 (TYRP-1) and -2 were also examined. The results demonstrate that treatment with HmHe significantly inhibits mushroom tyrosinase activity. Furthermore, HmHe also markedly inhibits melanin production and intracellular tyrosinase activity. By suppressing the expression of TYR, TYRP-1, TYRP-2, and MITF, HmHe treatment antagonized melanin production in melan-a cells. Additionally, HmHe interfered with the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, with reversal of HmHe-induced melanogenesis inhibition after treatment with specific inhibitor U0126. In summary, HmHe can be said to stimulate ERK1/2 phosphorylation and subsequent degradation of MITF, resulting in suppression of melanogenic enzymes and melanin production, possibly due to the presence of polyphenolic compounds.
Collapse
Affiliation(s)
- Md Badrul Alam
- Department of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Korea.
| | - Bum-Ju Seo
- Department of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Korea.
| | - Peijun Zhao
- Department of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Korea.
| | - Sang-Han Lee
- Department of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Korea.
| |
Collapse
|
21
|
Chun K, Alam MB, Son HU, Lee SH. Effect of Novel Compound LX519290, a Derivative of l-allo Threonine, on Antioxidant Potential in Vitro and in Vivo. Int J Mol Sci 2016; 17:ijms17091451. [PMID: 27598126 PMCID: PMC5037730 DOI: 10.3390/ijms17091451] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/09/2016] [Accepted: 08/19/2016] [Indexed: 11/16/2022] Open
Abstract
We investigated the antioxidative activity of LX519290, a derivative of l-allo threonine, in vitro and in vivo. To evaluate the antioxidative activity of LX519290, we performed several in vitro assays (2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical-scavenging assays, a ferric reducing antioxidant power assay, cupric-reducing antioxidant capacity, and oxygen radical absorbance capacity assay) and evaluated inhibition against the generation of nitric oxide (NO) and reactive oxygen species (ROS) in murine macrophage (RAW264.7) cells. The results showed that LX519290 possessed very strong radical scavenging activity and reducing power, and inhibited NO and ROS generation in a dose-dependent manner without showing any cytotoxicity. LX519290 treatment also increased the total thiol content and glutathione S-transferases (GST) activities in RAW264.7 cells. Finally, we also determined whether LX519290 affects the mRNA levels of antioxidant enzymes in vitro and in vivo. The expression of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were markedly higher in the sample-treated group than in the oxidative stress group. LX519290 treatment also increased the transcriptional and translational activities of NF-E2-related factor-2 (Nrf-2) with corresponding increases in the transcriptional and translational activities of haeme oxygenase-1 (HO-1). Collectively, the data demonstrated that LX519290 has potent antioxidative activity, decreases NO and ROS generation, increases total thiol content and GST activities in RAW264.7 cells, and increases the transcriptional and translational levels of antioxidant enzymes in vitro and in vivo.
Collapse
Affiliation(s)
- Kun Chun
- Department of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Korea.
- Research and Development (R&D) Center, Huons Co., Ltd., Ansan 15588, Korea.
| | - Md Badrul Alam
- Department of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Korea.
| | - Hyeong-U Son
- Department of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Korea.
| | - Sang-Han Lee
- Department of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Korea.
| |
Collapse
|
22
|
Greene LE, Godin R, Cosa G. Fluorogenic Ubiquinone Analogue for Monitoring Chemical and Biological Redox Processes. J Am Chem Soc 2016; 138:11327-34. [DOI: 10.1021/jacs.6b06899] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lana E. Greene
- Department of Chemistry and
Center for Self Assembled Chemical Structures (CSACS/CRMAA), McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3G 0B8, Canada
| | - Robert Godin
- Department of Chemistry and
Center for Self Assembled Chemical Structures (CSACS/CRMAA), McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3G 0B8, Canada
| | - Gonzalo Cosa
- Department of Chemistry and
Center for Self Assembled Chemical Structures (CSACS/CRMAA), McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3G 0B8, Canada
| |
Collapse
|
23
|
Impact of Antioxidants on Cardiolipin Oxidation in Liposomes: Why Mitochondrial Cardiolipin Serves as an Apoptotic Signal? OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:8679469. [PMID: 27313834 PMCID: PMC4899610 DOI: 10.1155/2016/8679469] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Revised: 02/29/2016] [Accepted: 03/17/2016] [Indexed: 01/08/2023]
Abstract
Molecules of mitochondrial cardiolipin (CL) get selectively oxidized upon oxidative stress, which triggers the intrinsic apoptotic pathway. In a chemical model most closely resembling the mitochondrial membrane-liposomes of pure bovine heart CL-we compared ubiquinol-10, ubiquinol-6, and alpha-tocopherol, the most widespread naturally occurring antioxidants, with man-made, quinol-based amphiphilic antioxidants. Lipid peroxidation was induced by addition of an azo initiator in the absence and presence of diverse antioxidants, respectively. The kinetics of CL oxidation was monitored via formation of conjugated dienes at 234 nm. We found that natural ubiquinols and ubiquinol-based amphiphilic antioxidants were equally efficient in protecting CL liposomes from peroxidation; the chromanol-based antioxidants, including alpha-tocopherol, were 2-3 times less efficient. Amphiphilic antioxidants, but not natural ubiquinols and alpha-tocopherol, were able, additionally, to protect the CL bilayer from oxidation by acting from the water phase. We suggest that the previously reported therapeutic efficiency of mitochondrially targeted amphiphilic antioxidants is owing to their ability to protect those CL molecules that are inaccessible to natural hydrophobic antioxidants, being trapped within respiratory supercomplexes. The high susceptibility of such occluded CL molecules to oxidation may have prompted their recruitment as apoptotic signaling molecules by nature.
Collapse
|
24
|
Morita M, Naito Y, Yoshikawa T, Niki E. Plasma lipid oxidation induced by peroxynitrite, hypochlorite, lipoxygenase and peroxyl radicals and its inhibition by antioxidants as assessed by diphenyl-1-pyrenylphosphine. Redox Biol 2016; 8:127-35. [PMID: 26774081 PMCID: PMC4732020 DOI: 10.1016/j.redox.2016.01.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/07/2016] [Accepted: 01/08/2016] [Indexed: 12/14/2022] Open
Abstract
Lipid oxidation has been implicated in the pathogenesis of many diseases. Lipids are oxidized in vivo by several different oxidants to give diverse products, in general lipid hydroperoxides as the major primary product. In the present study, the production of lipid hydroperoxides in the oxidation of mouse plasma induced by multiple oxidants was measured using diphenyl-1-pyrenylphosphine (DPPP) as a probe. DPPP itself is not fluorescent, but it reacts with lipid hydroperoxides stochiometrically to give highly fluorescent DPPP oxide and lipid hydroxides. The production of lipid hydroperoxides could be followed continuously in the oxidation of plasma induced by peroxynitrite, hypochlorite, 15-lipoxygenase, and peroxyl radicals with a microplate reader. A clear lag phase was observed in the plasma oxidation mediated by aqueous peroxyl radicals and peroxynitrite, but not in the oxidation induced by hypochlorite and lipoxygenase. The effects of several antioxidants against lipid oxidation induced by the above oxidants were assessed. The efficacy of antioxidants was dependent markedly on the type of oxidants. α-Tocopherol exerted potent antioxidant effects against peroxyl radical-mediated lipid peroxidation, but it did not inhibit lipid oxidation induced by peroxynitrite, hypochlorite, and 15-lipoxygenase efficiently, suggesting that multiple antioxidants with different selectivities are required for the inhibition of plasma lipid oxidation in vivo. This is a novel, simple and most high throughput method to follow plasma lipid oxidation induced by different oxidants and also to assess the antioxidant effects in biologically relevant settings.
Collapse
Affiliation(s)
- Mayuko Morita
- Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan; Department of Gastrointestinal Immunology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Yuji Naito
- Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Toshikazu Yoshikawa
- Department of Gastrointestinal Immunology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Etsuo Niki
- Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan; National Institute of Advanced Industrial Science & Technology, Health Research Institute, Takamatsu 761-0395, Japan.
| |
Collapse
|
25
|
Durand E, Zhao Y, Coupland JN, Elias RJ. Assessing Interactions between Lipophilic and Hydrophilic Antioxidants in Food Emulsions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:10655-10661. [PMID: 26479322 DOI: 10.1021/acs.jafc.5b04152] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Dietary lipids containing high concentrations of polyunsaturated fatty acids are considered to be beneficial to human health, yet their incorporation within formulated foods is complicated by their susceptibility to oxidation. Lipid oxidation in foods is inhibited through the incorporation of antioxidants, yet the list of antioxidants approved for food use is small, and consumers frequently demand foods without synthetic additives. As a consequence, food processors are now tasked with improving the efficacy of approved, "natural" (i.e., nonsynthetic) antioxidants; a rational strategy for doing so involves localizing the antioxidants at the interface where oxidation usually occurs and regenerating the consumed antioxidants after the oxidation event has occurred. The present study describes a procedure to evaluate antioxidant interactions in oil-in-water food emulsions, which is based on controlled oxidation reactions induced in the dispersed oil phase by the lipophilic radical generator, 2,2'-azobis(2,4-dimethylvaleronitrile). The extent of lipid oxidation is measured spectroscopically by following the loss of an oxidatively labile, lipophilic probe (methyl eleostearate), the synthesis of which is described here. Using this procedure, the ability of various aqueous phase solvated antioxidants (ascorbic acid, gallic acid, (-)-epicatechin, (-)-epigallocatechin-3-gallate) to regenerate lipid phase solvated α-tocopherol was evaluated. In all cases, the test compounds were able to inhibit oxidation reactions; however, these effects were not profoundly synergistic, and the maximum synergistic interaction observed was only ∼ 3% using ascorbic acid.
Collapse
Affiliation(s)
- Erwann Durand
- Department of Food Science, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Yu Zhao
- Department of Food Science, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - John N Coupland
- Department of Food Science, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Ryan J Elias
- Department of Food Science, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| |
Collapse
|
26
|
Li B, Zheng F, Chauvin JPR, Pratt DA. The medicinal thiosulfinates from garlic and Petiveria are not radical-trapping antioxidants in liposomes and cells, but lipophilic analogs are. Chem Sci 2015; 6:6165-6178. [PMID: 30090232 PMCID: PMC6054074 DOI: 10.1039/c5sc02270c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 07/27/2015] [Indexed: 01/11/2023] Open
Abstract
The radical-trapping antioxidant (RTA) activities of allicin and petivericin, thiosulfinates widely believed responsible for the medicinal properties of garlic and Petiveria, were determined in phosphatidylcholine lipid bilayers and mammalian cell culture.
The radical-trapping antioxidant (RTA) activities of allicin and petivericin, thiosulfinates widely believed responsible for the medicinal properties of garlic and Petiveria, were determined in phosphatidylcholine lipid bilayers. The results indicate that both compounds are surprisingly ineffective, in sharp contrast with previous studies in organic solution which showed that they undergo facile Cope elimination to produce sulfenic acids – potent radical-trapping agents. In an effort to understand the medium dependence of this activity, a more lipophilic (hexylated) analog of petivericin was synthesized and shown to be among the most effective RTAs known, but only in the presence of a hydrophilic thiol (e.g. N-acetylcysteine). Additional symmetric and unsymmetric thiosulfinates were synthesized to shed light on the structural features that underlie this reactivity. These studies reveal that amphiphilic thiosulfinates which undergo S-thiolation with a hydrophilic thiol to give lipophilic sulfenic acids are required, and that an activated methylene group – key to promote Cope elimination – is not. Interestingly, the added thiol was also found to regenerate the sulfenic acid following its reaction with peroxyl radicals. This activity was diminished at more acidic pH, suggesting that it occurs by electron transfer from the thiolate. Allicin, petivericin and hexylated petivericin were assayed as inhibitors of lipid peroxidation in human TF1a erythroblasts and HEK-293 kidney cells, revealing similar efficacies in the low μM range – the same range in which allicin and petivericin were found to induce cell death concomitant with, or as a result of, glutathione (GSH) depletion. In contrast, hexylated petivericin was not cytotoxic throughout the concentration range assayed, and had no effect on GSH levels. Taken together, the results in lipid bilayers and in cell culture suggest that the greater lipophilicity of hexylated petivericin enables it to partition to membranous cell compartments where it forms a lipid-soluble sulfenic acid that traps peroxyl radicals, whereas allicin and petivericin partition to the cytosol where they deplete GSH and induce cell death.
Collapse
Affiliation(s)
- Bo Li
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , 10 Marie Curie Pvt. , Ottawa , Ontario , Canada . ; ; Tel: +1-613-562-5800 ext. 2119
| | - Feng Zheng
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , 10 Marie Curie Pvt. , Ottawa , Ontario , Canada . ; ; Tel: +1-613-562-5800 ext. 2119
| | - Jean-Philippe R Chauvin
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , 10 Marie Curie Pvt. , Ottawa , Ontario , Canada . ; ; Tel: +1-613-562-5800 ext. 2119
| | - Derek A Pratt
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , 10 Marie Curie Pvt. , Ottawa , Ontario , Canada . ; ; Tel: +1-613-562-5800 ext. 2119
| |
Collapse
|
27
|
Li B, Pratt DA. Methods for determining the efficacy of radical-trapping antioxidants. Free Radic Biol Med 2015; 82:187-202. [PMID: 25660993 DOI: 10.1016/j.freeradbiomed.2015.01.020] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/20/2015] [Accepted: 01/22/2015] [Indexed: 01/10/2023]
Abstract
Hydrocarbon autoxidation is the free radical chain reaction primarily responsible for the oxidative degradation of organic materials, including those that make up cells, tissues, and organs. The identification of compounds that slow this process (antioxidants) and the quantitation of their efficacies have long been goals of academic and industrial researchers. Antioxidants are generally divided into two types: preventive and radical-trapping (also commonly referred to as chain-breaking). Preventive antioxidants slow the rate of initiation of autoxidation, whereas radical-trapping antioxidants slow the rate of propagation by reacting with chain-propagating peroxyl radicals. The purpose of this review is to provide a comprehensive overview of different approaches to measure the kinetics of the reactions of radical-trapping antioxidants with peroxyl radicals, and their use to study the inhibition of hydrocarbon (lipid) autoxidation in homogeneous solution, as well as biphasic media (lipid bilayers) and cell culture. Direct and indirect approaches are presented and advantages and disadvantages of each are discussed in order to facilitate method selection for investigators seeking to address particular questions in this immensely popular field.
Collapse
Affiliation(s)
- Bo Li
- Department of Chemistry, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Derek A Pratt
- Department of Chemistry, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
| |
Collapse
|
28
|
Iwaoka M, Sano N, Lin YY, Katakura A, Noguchi M, Takahashi K, Kumakura F, Arai K, Singh BG, Kunwar A, Priyadarsini KI. Fatty Acid Conjugates of Water-Soluble (±)-trans-Selenolane-3,4-diol: Effects of Alkyl Chain Length on the Antioxidant Capacity. Chembiochem 2015; 16:1226-34. [DOI: 10.1002/cbic.201500047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Indexed: 11/11/2022]
|
29
|
Lokhmatikov AV, Voskoboynikova NE, Cherepanov DA, Sumbatyan NV, Korshunova GA, Skulachev MV, Steinhoff HJ, Skulachev VP, Mulkidjanian AY. Prevention of peroxidation of cardiolipin liposomes by quinol-based antioxidants. BIOCHEMISTRY (MOSCOW) 2014; 79:1081-100. [DOI: 10.1134/s0006297914100101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
30
|
He RR, Li Y, Li XD, Yi RN, Wang XY, Tsoi B, Lee KKH, Abe K, Yang X, Kurihara H. A new oxidative stress model, 2,2-azobis(2-amidinopropane) dihydrochloride induces cardiovascular damages in chicken embryo. PLoS One 2013; 8:e57732. [PMID: 23469224 PMCID: PMC3585800 DOI: 10.1371/journal.pone.0057732] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 01/25/2013] [Indexed: 01/22/2023] Open
Abstract
It is now well established that the developing embryo is very sensitive to oxidative stress, which is a contributing factor to pregnancy-related disorders. However, little is known about the effects of reactive oxygen species (ROS) on the embryonic cardiovascular system due to a lack of appropriate ROS control method in the placenta. In this study, a small molecule called 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH), a free radicals generator, was used to study the effects of oxidative stress on the cardiovascular system during chick embryo development. When nine-day-old (stage HH 35) chick embryos were treated with different concentrations of AAPH inside the air chamber, it was established that the LD50 value for AAPH was 10 µmol/egg. At this concentration, AAPH was found to significantly reduce the density of blood vessel plexus that was developed in the chorioallantoic membrane (CAM) of HH 35 chick embryos. Impacts of AAPH on younger embryos were also examined and discovered that it inhibited the development of vascular plexus on yolk sac in HH 18 embryos. AAPH also dramatically repressed the development of blood islands in HH 3+ embryos. These results implied that AAPH-induced oxidative stress could impair the whole developmental processes associated with vasculogenesis and angiogenesis. Furthermore, we observed heart enlargement in the HH 40 embryo following AAPH treatment, where the left ventricle and interventricular septum were found to be thickened in a dose-dependent manner due to myocardiac cell hypertrophy. In conclusion, oxidative stress, induced by AAPH, could lead to damage of the cardiovascular system in the developing chick embryo. The current study also provided a new developmental model, as an alternative for animal and cell models, for testing small molecules and drugs that have anti-oxidative activities.
Collapse
Affiliation(s)
- Rong-Rong He
- Pharmacy College, Jinan University, Guangzhou, People’s Republic of China
| | - Yan Li
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, People’s Republic of China
| | - Xiao-Di Li
- Pharmacy College, Jinan University, Guangzhou, People’s Republic of China
| | - Ruo-Nan Yi
- Pharmacy College, Jinan University, Guangzhou, People’s Republic of China
| | - Xiao-Yu Wang
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, People’s Republic of China
| | - Bun Tsoi
- Pharmacy College, Jinan University, Guangzhou, People’s Republic of China
| | - Kenneth Ka Ho Lee
- Stem Cell and Regeneration Thematic Research Programme, School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Keiichi Abe
- BRAND’s Health Science Centre, Scientific Research Division, Singapore, Singapore
| | - Xuesong Yang
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, People’s Republic of China
- * E-mail: (XY); (HK)
| | - Hiroshi Kurihara
- Pharmacy College, Jinan University, Guangzhou, People’s Republic of China
- * E-mail: (XY); (HK)
| |
Collapse
|
31
|
Li B, Harjani JR, Cormier NS, Madarati H, Atkinson J, Cosa G, Pratt DA. Besting Vitamin E: Sidechain Substitution is Key to the Reactivity of Naphthyridinol Antioxidants in Lipid Bilayers. J Am Chem Soc 2013; 135:1394-405. [DOI: 10.1021/ja309153x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bo Li
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Jitendra R. Harjani
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Nicholas S. Cormier
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Hasam Madarati
- Department of Chemistry and
Centre for Biotechnology, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Jeffrey Atkinson
- Department of Chemistry and
Centre for Biotechnology, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Gonzalo Cosa
- Department of Chemistry and Centre
for Self-Assembled Chemical Structures, McGill University, 801 Sherbrooke St. West, Montreal, Quebec H3A 0B8 Canada
| | - Derek A. Pratt
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| |
Collapse
|
32
|
Zheng F, Pratt DA. Antioxidant generation and regeneration in lipid bilayers: the amazing case of lipophilic thiosulfinates and hydrophilic thiols. Chem Commun (Camb) 2013; 49:8181-3. [DOI: 10.1039/c3cc44401e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
33
|
Hill S, Lamberson CR, Xu L, To R, Tsui HS, Shmanai VV, Bekish AV, Awad AM, Marbois BN, Cantor CR, Porter NA, Clarke CF, Shchepinov MS. Small amounts of isotope-reinforced polyunsaturated fatty acids suppress lipid autoxidation. Free Radic Biol Med 2012; 53:893-906. [PMID: 22705367 PMCID: PMC3437768 DOI: 10.1016/j.freeradbiomed.2012.06.004] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 05/08/2012] [Accepted: 06/01/2012] [Indexed: 01/13/2023]
Abstract
Polyunsaturated fatty acids (PUFAs) undergo autoxidation and generate reactive carbonyl compounds that are toxic to cells and associated with apoptotic cell death, age-related neurodegenerative diseases, and atherosclerosis. PUFA autoxidation is initiated by the abstraction of bis-allylic hydrogen atoms. Replacement of the bis-allylic hydrogen atoms with deuterium atoms (termed site-specific isotope-reinforcement) arrests PUFA autoxidation due to the isotope effect. Kinetic competition experiments show that the kinetic isotope effect for the propagation rate constant of Lin autoxidation compared to that of 11,11-D(2)-Lin is 12.8 ± 0.6. We investigate the effects of different isotope-reinforced PUFAs and natural PUFAs on the viability of coenzyme Q-deficient Saccharomyces cerevisiae coq mutants and wild-type yeast subjected to copper stress. Cells treated with a C11-BODIPY fluorescent probe to monitor lipid oxidation products show that lipid peroxidation precedes the loss of viability due to H-PUFA toxicity. We show that replacement of just one bis-allylic hydrogen atom with deuterium is sufficient to arrest lipid autoxidation. In contrast, PUFAs reinforced with two deuterium atoms at mono-allylic sites remain susceptible to autoxidation. Surprisingly, yeast treated with a mixture of approximately 20%:80% isotope-reinforced D-PUFA:natural H-PUFA are protected from lipid autoxidation-mediated cell killing. The findings reported here show that inclusion of only a small fraction of PUFAs deuterated at the bis-allylic sites is sufficient to profoundly inhibit the chain reaction of nondeuterated PUFAs in yeast.
Collapse
Affiliation(s)
- Shauna Hill
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, 607 Charles E. Young Dr. E., Los Angeles, CA 90095-1569
| | | | - Libin Xu
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235
| | - Randy To
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, 607 Charles E. Young Dr. E., Los Angeles, CA 90095-1569
| | - Hui S. Tsui
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, 607 Charles E. Young Dr. E., Los Angeles, CA 90095-1569
| | - Vadim V. Shmanai
- Institute of Physical Organic Chemistry, National Academy of Science of Belarus, 13 Surganova Street, Minsk 220072, Belarus
| | - Andrei V. Bekish
- Department of Chemistry, Belarusian State University, Minsk 220020, Belarus
| | - Agape M. Awad
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, 607 Charles E. Young Dr. E., Los Angeles, CA 90095-1569
| | - Beth N. Marbois
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, 607 Charles E. Young Dr. E., Los Angeles, CA 90095-1569
| | - Charles R. Cantor
- The Scripps Research Institute, Department of Molecular Biology, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Retrotope Inc., 12133 Foothill Lane, Los Altos Hills, CA 94022
| | - Ned A. Porter
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235
| | - Catherine F. Clarke
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, 607 Charles E. Young Dr. E., Los Angeles, CA 90095-1569
- To whom correspondence should be addressed: Catherine F. Clarke, Tel. 310.825.0771, Fax. 310.206.5213, ; and Mikhail S. Shchepinov, Tel. 650.917.9256, Fax. 650.917.9255,
| | - Mikhail S. Shchepinov
- Retrotope Inc., 12133 Foothill Lane, Los Altos Hills, CA 94022
- To whom correspondence should be addressed: Catherine F. Clarke, Tel. 310.825.0771, Fax. 310.206.5213, ; and Mikhail S. Shchepinov, Tel. 650.917.9256, Fax. 650.917.9255,
| |
Collapse
|
34
|
Krumova K, Friedland S, Cosa G. How lipid unsaturation, peroxyl radical partitioning, and chromanol lipophilic tail affect the antioxidant activity of α-tocopherol: direct visualization via high-throughput fluorescence studies conducted with fluorogenic α-tocopherol analogues. J Am Chem Soc 2012; 134:10102-13. [PMID: 22568598 DOI: 10.1021/ja301680m] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The preparation of two highly sensitive fluorogenic α-tocopherol (TOH) analogues which undergo >30-fold fluorescence intensity enhancement upon reaction with peroxyl radicals is reported. The probes consist of a chromanol moiety coupled to the meso position of a BODIPY fluorophore, where the use of a methylene linker (BODIPY-2,2,5,7,8-pentamethyl-6-hydroxy-chroman adduct, H(2)B-PMHC) vs an ester linker (meso-methanoyl BODIPY-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid, H(2)B-TOH) enables tuning their reactivity toward H-atom abstraction by peroxyl radicals. The development of a high-throughput fluorescence assay for monitoring kinetics of peroxyl radical reactions in liposomes is subsequently described where the evolution of the fluorescence intensity over time provides a rapid, facile method to conduct competitive kinetic studies in the presence of TOH and its analogues. A quantitative treatment is formulated for the temporal evolution of the intensity in terms of relative rate constants of H-atom abstraction (k(inh)) from the various tocopherol analogues. Combined, the new probes, the fluorescence assay, and the data analysis provide a new method to obtain, in a rapid, parallel format, relative antioxidant activities in phospholipid membranes. The method is exemplified with four chromanol-based antioxidant compounds differing in their aliphatic tails (TOH, PMHC, H(2)B-PMHC, and H(2)B-TOH). Studies were conducted in six different liposome solutions prepared from poly- and mono-unsaturated and saturated (fluid vs gel phase) lipids in the presence of either hydrophilic or lipophilic peroxyl radicals. A number of key insights into the chemistry of the TOH antioxidants in lipid membranes are provided: (1) The relative antioxidant activities of chromanols in homogeneous solution, arising from their inherent chemical reactivity, readily translate to the microheterogeneous environment at the water/lipid interface; thus similar values for k(inh)(H(2)B-PMHC)/k(inh)(H(2)B-TOH) in the range of 2-3 are recorded both in homogeneous solution and in liposome suspensions with hydrophilic or lipophilic peroxyl radicals. (2) The relative antioxidant activity between tocopherol analogues with the same inherent chemical reactivity but bearing short (PMHC) or long (TOH) aliphatic tails, k(inh)(PMHC)/k(inh)(TOH), is ~8 in the presence of hydrophilic peroxyl radicals, regardless of the nature of the lipid membrane into which they are embedded. (3) Antioxidants embedded in saturated lipids do not efficiently scavenge hydrophilic peroxyl radicals; under these conditions wastage reactions among peroxyl radicals become important, and this translates into larger times for antioxidant consumption. (4) Lipophilic peroxyl radicals show reduced discrimination between antioxidants bearing long and short aliphatic tails, with k(inh)(PMHC)/k(inh)(TOH) in the range of 3-4 for most lipid membranes. (5) Lipophilic peroxyl radicals are scavenged with the same efficiency by all four antioxidants studied, regardless of the nature of their aliphatic tail or the lipid membrane into which they are embedded. These data underpin the key role the lipid environment plays in modulating the rate of reaction of antioxidants characterized by similar inherent chemical reactivity (arising from a conserved chromanol moiety) but differing in their membrane mobility (structural differences in the lipophilic tail). Altogether, a novel, facile method of study, new insights, and a quantitative understanding on the critical role of lipid diversity in modulating antioxidant activity in the lipid milieu are reported.
Collapse
Affiliation(s)
- Katerina Krumova
- Department of Chemistry and Center for Self Assembled Chemical Structures, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 2K6, Canada
| | | | | |
Collapse
|
35
|
Takashima M, Horie M, Shichiri M, Hagihara Y, Yoshida Y, Niki E. Assessment of antioxidant capacity for scavenging free radicals in vitro: a rational basis and practical application. Free Radic Biol Med 2012; 52:1242-52. [PMID: 22306582 DOI: 10.1016/j.freeradbiomed.2012.01.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 12/07/2011] [Accepted: 01/14/2012] [Indexed: 11/19/2022]
Abstract
With increasing evidence showing the involvement of oxidative stress induced by free radicals in the development of various diseases, the role of radical-scavenging antioxidants has received much attention. Although many randomized controlled clinical trials do not support the beneficial effects of indiscriminate supplementation of antioxidants, more recent studies suggest that antioxidants such as vitamin E may be effective for prevention and treatment of some diseases when given to the right subjects at the right time. Many studies on the antioxidant capacity assessed by various available methods showed inconsistent results and the assessment of antioxidant capacity has been the subject of extensive studies and arguments. This study was performed to elucidate the basic chemistry required for the development of a reliable method for the assessment of antioxidant capacity for radical scavenging in vitro. In this study, the capacity of α-tocopherol and its related compounds, ascorbic acid, and uric acid for scavenging radicals was assessed from their effects on the rate of decay of hydrophilic and lipophilic probes with various reactivities toward free radicals induced by hydrophilic and lipophilic radicals in homogeneous solution and heterogeneous micelle systems. Fluorescein, pyranine, and pyrogallol red were used as hydrophilic probes, and BODIPY and N,N-diphenyl-p-phenylenediamine were used as lipophilic probes. We show that the rate and amount of radical scavenging by antioxidants, termed the antioxidant radical absorbance capacity, could be assessed by an appropriate combination of radical initiator and probe. This method was applied to the assessment of radical-scavenging capacity of human plasma, wine, and green tea powder.
Collapse
Affiliation(s)
- Mizuki Takashima
- Health Research Institute, National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka 563-8577, Japan
| | | | | | | | | | | |
Collapse
|
36
|
Hanthorn JJ, Haidasz E, Gebhardt P, Pratt DA. A versatile fluorescence approach to kinetic studies of hydrocarbon autoxidations and their inhibition by radical-trapping antioxidants. Chem Commun (Camb) 2012; 48:10141-3. [DOI: 10.1039/c2cc35214a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
37
|
Takashima M, Shichiri M, Hagihara Y, Yoshida Y, Niki E. Capacity of peroxyl radical scavenging and inhibition of lipid peroxidation by β-carotene, lycopene, and commercial tomato juice. Food Funct 2012; 3:1153-60. [DOI: 10.1039/c2fo30119a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
38
|
Yin H, Xu L, Porter NA. Free Radical Lipid Peroxidation: Mechanisms and Analysis. Chem Rev 2011; 111:5944-72. [DOI: 10.1021/cr200084z] [Citation(s) in RCA: 1195] [Impact Index Per Article: 91.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Huiyong Yin
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Departments of Medicine and Pharmacology, Division of Clinical Pharmacology, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Libin Xu
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Ned A. Porter
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| |
Collapse
|
39
|
Cetojević-Simin DD, Canadanović-Brunet JM, Bogdanović GM, Djilas SM, Cetković GS, Tumbas VT, Stojiljković BT. Antioxidative and antiproliferative activities of different horsetail (Equisetum arvense L.) extracts. J Med Food 2010; 13:452-9. [PMID: 20170379 DOI: 10.1089/jmf.2008.0159] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this study we investigated antioxidative and antiproliferative activity of different horsetail (Equisetum arvense L.) extracts. The antioxidative activity was measured by the electron spin resonance (ESR) spectroscopy-spin trapping method. The influence of different horsetail extracts during lipid peroxidation of (1) sunflower oil induced by the lipophilic azo-initiator 4,4'-azobis(4-cyanovaleric acid) and (2) soybean phosphatidylcholine liposomes induced by the hydrophilic azo-initiator 2,2'-azobis(2-amidinopropane) dihydrochloride was studied. Antiproliferative activity was measured using the sulforhodamine B colorimetric assay on the human cancer cell lines HeLa, HT-29, and MCF7. The results of ESR analysis confirmed that the extracts investigated suppressed the formation of lipid peroxyl radicals in both systems investigated in a dose-dependent manner. The results indicate that n-butanol, methanol, ethyl acetate, and water extracts had significant peroxyl radical scavenging activity. Extracts inhibited cell growth that was dependent on cell line, type of extract, and extract concentration. Ethyl acetate extract exhibited the most prominent antiproliferative effect, without inducing any cell growth stimulation on human tumor cell lines. The results obtained suggest that the horsetail extracts could be used as an easily accessible source of natural antioxidants and as potential phytochemicals.
Collapse
|
40
|
Mosca M, Ceglie A, Ambrosone L. Lipid Oxidation in Water-in-Olive Oil Emulsions Initiated by a Lipophilic Radical Source. J Phys Chem B 2010; 114:3550-8. [DOI: 10.1021/jp911288e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Monica Mosca
- Consorzio per lo sviluppo dei sistemi a grande interfase (C.S.G.I.) C/O Department of Food Technology, DISTAAM, Università del Molise, Via De Sanctis 86100, Campobasso, Italy
| | - Andrea Ceglie
- Consorzio per lo sviluppo dei sistemi a grande interfase (C.S.G.I.) C/O Department of Food Technology, DISTAAM, Università del Molise, Via De Sanctis 86100, Campobasso, Italy
| | - Luigi Ambrosone
- Consorzio per lo sviluppo dei sistemi a grande interfase (C.S.G.I.) C/O Department of Food Technology, DISTAAM, Università del Molise, Via De Sanctis 86100, Campobasso, Italy
| |
Collapse
|
41
|
Yoshida Y, Itoh N, Saito Y, Hayakawa M, Niki E. Application of Water-Soluble Radical Initiator, 2,2′-Azobis-[2-(2-imidazolin-2-yl)propane] Dihydrochloride, to a Study of Oxidative Stress. Free Radic Res 2009; 38:375-84. [PMID: 15190934 DOI: 10.1080/1071576042000191763] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
It is essential to generate free radicals at a controled and constant rate for specific duration and at specific site to study the dynamics of oxidation and also antioxidation. Both hydrophilic and lipophilic azo compounds have been used for such purpose. In the present work, the action of 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (AIPH) was examined and compared with those of 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)-propionamide] (AMHP). The rate constant of free radical formation (ek(d)) for AIPH was 2.6 x 10(-6)/s at 37 degrees C in PBS (pH 7.4) solution, indicating that AIPH gives 3.8 times more free radicals than AAPH under the same conditions. It was found that the dynamics of oxidation and antioxidation induced by AIPH can be studied satisfactorily in the oxidation in micelles, LDL and erythrocyte suspensions, plasma, and cultured cells. The extent of cell death induced by AIPH and AAPH was directly proportional to the total free radicals formed. Interestingly, it was found that rats would not drink water containing AAPH, but they drank water containing AIPH. The levels of 8-iso-prostaglandin F2alpha (8-isoPs), 7-hydroxycholesterol (FCOH), lysophosphatidylcholine in the plasma of rats given water containing 50 mM AIPH for 1 month increased compared with those of control rats which drank water without AIPH. It may be concluded that AIPH is useful for kinetic and mechanistic studies on oxidative stress to membranes, lipoproteins, cells, and even animal models.
Collapse
Affiliation(s)
- Yasukazu Yoshida
- Human Stress Signal Research Center, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
| | | | | | | | | |
Collapse
|
42
|
Synergistic interactions of antioxidant nutrients in a biological model system. Nutrition 2009; 25:839-46. [DOI: 10.1016/j.nut.2009.01.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 01/22/2009] [Accepted: 01/24/2009] [Indexed: 02/07/2023]
|
43
|
Park HY, Lee HS, Cho EJ. Protective Activity of Seolitae Chungkukjang Added with Green Tea against Cellular Oxidative Stress induced by AAPH. Prev Nutr Food Sci 2009. [DOI: 10.3746/jfn.2009.14.1.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
44
|
Piao X, Piao XL, Kim HY, Cho EJ. Antioxidative activity of geranium (Pelargonium inquinans Ait) and its active component, 1,2,3,4,6-penta-O-galloyl-beta-D-glucose. Phytother Res 2008; 22:534-8. [PMID: 18386256 DOI: 10.1002/ptr.2398] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The antioxidative activity of geranium (Pelargonium inquinans Ait) and its active component was investigated under in vitro and cellular oxidative stress models. The MeOH extract, and n-hexane, EtOAc, BuOH and H(2)O fractions from geranium showed strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effects and protective potential from oxidative damage by the radical generator, 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) in renal epithelial LLC-PK(1) cells. In particular, the EtOAc fraction exerted the strongest antioxidative potential in not only the in vitro but also in the cellular system. It suggests that the antioxidative activity of geranium is attributed mainly to components from the EtOAc fraction. Furthermore, the active component, 1,2,3,4,6-penta-O-galloyl-beta-d-glucose (PGG), was identified from the EtOAc fraction by the bioassay-linked fractionation method. It displayed a potent antioxidant effect against the DPPH radical, showing an IC(50) value of 1.14 microg/mL. Moreover, the compound recovered the cell viability declined by AAPH treatment significantly and dose-dependently, implying a protective role against cellular oxidative damage. The present study suggests that geranium has an excellent antioxidative potential and that PGG from geranium is considered to be the active component with an antioxidative effect.
Collapse
Affiliation(s)
- Xiangshu Piao
- College of Animal Science and Technology, China Agriculture University, Beijing 100094, China
| | | | | | | |
Collapse
|
45
|
Laguerre M, Lecomte J, Villeneuve P. Evaluation of the ability of antioxidants to counteract lipid oxidation: Existing methods, new trends and challenges. Prog Lipid Res 2007; 46:244-82. [PMID: 17651808 DOI: 10.1016/j.plipres.2007.05.002] [Citation(s) in RCA: 365] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Revised: 05/09/2007] [Accepted: 05/11/2007] [Indexed: 12/12/2022]
Abstract
Oxidative degradation of lipids, especially that induced by reactive oxygen species (ROS), leads to quality deterioration of foods and cosmetics and could have harmful effects on health. Currently, a very promising way to overcome this is to use vegetable antioxidants for nutritional, therapeutic or food quality preservation purposes. A major challenge is to develop tools to assess the antioxidant capacity and real efficacy of these molecules. Many rapid in vitro tests are now available, but they are often performed in dissimilar conditions and different properties are thus frequently measured. The so-called 'direct' methods, which use oxidizable substrates, seem to be the only ones capable of measuring real antioxidant power. Some oxidizable substrates correspond to molecules or natural extracts exhibiting biological activity, such as lipids, proteins or nucleic acids, while others are model substrates that are not encountered in biological systems or foods. Only lipid oxidation and direct methods using lipid-like substrates will be discussed in this review. The main mechanisms of autoxidation and antioxidation are recapitulated, then the four components of a standard test (oxidizable substrate, medium, oxidation conditions and antioxidant) applied to a single antioxidant or complex mixtures are dealt with successively. The study is focused particularly on model lipids, but also on dietary and biological lipids isolated from their natural environment, including lipoproteins and phospholipidic membranes. Then the advantages and drawbacks of existing methods and new approaches are compared according to the context. Finally, recent trends based on the chemometric strategy are introduced as a highly promising prospect for harmonizing in vitro methods.
Collapse
Affiliation(s)
- M Laguerre
- UMR 1208 Ingénierie des Agropolymères et Technologies Emergentes, CIRAD, INRA, Montpellier SupAgro, Université Montpellier 2, F-34000 Montpellier, France
| | | | | |
Collapse
|
46
|
Bi Y, Yang G, Li H, Zhang G, Guo Z. Characterization of the chemical composition of lotus plumule oil. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2006; 54:7672-7. [PMID: 17002438 DOI: 10.1021/jf0607011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Characterizations of lotus plumule and plumule oil, focusing on approximate composition analysis of lotus plumule powder and fatty acid composition, lipid classes, triglyceride (TG) profiles, and sterol analysis of the plumule oil, were conducted in this work. The results revealed that the lotus plumule constitutes 7.8% moisture, 4.2% ash, and 12.5% crude oil and 26.3% protein on the dry base. Lotus plumule oil is rich in linoleic acid (50.4%) and oleic acid (13.5%), and the dominating saturated fatty acids are palmitic acid (18.0%) and behenic acid (6.8%). The principal components of TG in lotus plumule oil are LLL (12.80%), beta-PLL (11.27%), beta-POL (8.28%), beta-PLO (8.58%), and beta-BeLL (8.32%). Lipid class assay of the crude oil gave the saponification value of 153.4 KOH mg/g and tocopherol content 390 mg/100 g. A distinct characteristic of lotus plumule oil is that its unsaponifiable matter is incredibly high, up to 14-19%, which consists mainly of beta-sitosterol (32%), Delta(5)-avenasterol (20%), and campesterol (6.3%). The major occurring form of sterols was found to be steryl ester. This work might be useful to develop innovative applications of lotus plumule oil.
Collapse
Affiliation(s)
- Yanlan Bi
- Lipid Technology and Engineering, School of Food Science and Engineering, Henan University of Technology, Zhengzhou 450052, People's Republic of China
| | | | | | | | | |
Collapse
|
47
|
Calla MS, Lynch SM. Vitamin C preserves the cardio-protective paraoxonase activity of high-density lipoprotein during oxidant stress. Arch Biochem Biophys 2006; 452:129-37. [PMID: 16854368 DOI: 10.1016/j.abb.2006.06.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 06/01/2006] [Accepted: 06/13/2006] [Indexed: 02/02/2023]
Abstract
HDL-associated paraoxonase (PON) antioxidant enzyme activity is cardio-protective. We investigated whether vitamin C prevented loss of PON activity from HDL during oxidant stress. HDL was incubated with either hydrophilic or lipophilic peroxyl radical initiators in the absence (control) or presence of vitamin C (50 and 100 micromol/L). Regardless of the type of radical, accumulation of lipid oxidation products in HDL was similar in incubations lacking vitamin C. Loss of PON activity was greater in HDL exposed to hydrophilic, in contrast to lipophilic, radicals, but addition of vitamin C maintained enzyme activity. Vitamin C's capacity to attenuate loss of the HDL ability to prevent atherogenic modification of LDL (assessed as electrophoretic mobility) was, however, modest, and appeared limited only to those incubations in which HDL was exposed to lipophilic radicals. Our results indicate that vitamin C may, under some conditions, prevent loss of cardio-protective function from HDL during oxidant stress.
Collapse
Affiliation(s)
- Melody S Calla
- Department of Biochemistry, Midwestern University, Downers Grove, IL 60515, USA
| | | |
Collapse
|
48
|
Canadanovic-Brunet JM, Djilas SM, Cetkovic GS, Tumbas VT, Mandic AI, Canadanovic VM. Antioxidant activities of different Teucrium montanum L. Extracts. Int J Food Sci Technol 2006. [DOI: 10.1111/j.1365-2621.2006.01133.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
49
|
Koshiishi I, Tsuchida K, Takajo T, Komatsu M. Radical scavenger can scavenge lipid allyl radicals complexed with lipoxygenase at lower oxygen content. Biochem J 2006; 395:303-9. [PMID: 16396633 PMCID: PMC1422755 DOI: 10.1042/bj20051595] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Revised: 12/21/2005] [Accepted: 01/06/2006] [Indexed: 11/17/2022]
Abstract
Lipoxygenases have been proposed to be a possible factor that is responsible for the pathology of certain diseases, including ischaemic injury. In the peroxidation process of linoleic acid by lipoxygenase, the E,Z-linoleate allyl radical-lipoxygenase complex seems to be generated as an intermediate. In the present study, we evaluated whether E,Z-linoleate allyl radicals on the enzyme are scavenged by radical scavengers. Linoleic acid, the content of which was greater than the dissolved oxygen content, was treated with soya bean lipoxygenase-1 (ferric form) in the presence of radical scavenger, CmP (3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl). The reaction rate between oxygen and lipid allyl radical is comparatively faster than that between CmP and lipid allyl radical. Therefore a reaction between linoleate allyl radical and CmP was not observed while the dioxygenation of linoleic acid was ongoing. After the dissolved oxygen was depleted, CmP stoichiometrically trapped linoleate-allyl radicals. Accompanied by this one-electron redox reaction, the resulting ferrous lipoxygenase was re-oxidized to the ferric form by hydroperoxylinoleate. Through the adduct assay via LC (liquid chromatography)-MS/MS (tandem MS), four E,Z-linoleate allyl radical-CmP adducts corresponding to regio- and diastereo-isomers were detected in the linoleate/lipoxygenase system, whereas E,E-linoleate allyl radical-CmP adducts were not detected at all. If E,Z-linoleate allyl radical is liberated from the enzyme, the E/Z-isomer has to reach equilibrium with the thermodynamically favoured E/E-isomer. These data suggested that the E,Z-linoleate allyl radicals were not liberated from the active site of lipoxygenase before being trapped by CmP. Consequently, we concluded that the lipid allyl radicals complexed with lipoxygenase could be scavenged by radical scavengers at lower oxygen content.
Collapse
Key Words
- ischaemic injury
- lipid allyl radical
- lipid epoxyallyl radical
- lipoxygenase
- polyunsaturated fatty acid (pufa)
- radical scavenger
- amvn, 2,2′-azobis(2,4-dimethylvaleronitrile)
- cmp, 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrrolidine-n-oxyl
- cmδp, 3-carbamoyl-2,2,5,5-tetramethylpyrroline-n-oxyl
- epi, enhanced product ion scanning
- esi, electrospray ionization
- [la], linoleic acid concentration
- [la-ooh], hydroperoxylinoleic acid concentration
- lc, liquid chromatography
- ms/ms, tandem ms
- pla2, phospholipase a2
- pufa, polyunsaturated fatty acid
- tic, total ion chromatogram
- xic, extracted ion chromatogram
Collapse
Affiliation(s)
- Ichiro Koshiishi
- Nihon Pharmaceutical University, 10281 Komuro, Ina-machi, Kita-Adachi-gun, Saitama, 362-0806 Japan.
| | | | | | | |
Collapse
|
50
|
Koshiishi I, Tsuchida K, Takajo T, Komatsu M. Quantification of lipid alkyl radicals trapped with nitroxyl radical via HPLC with postcolumn thermal decomposition. J Lipid Res 2005; 46:2506-13. [PMID: 16106053 DOI: 10.1194/jlr.d500006-jlr200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipid alkyl radicals generated from polyunsaturated fatty acids via chemical or enzymatic H-abstraction have been a pathologically important target to quantify. In the present study, we established a novel method for the quantification of lipid alkyl radicals via nitroxyl radical spin-trapping. These labile lipid alkyl radicals were converted into nitroxyl radical-lipid alkyl radical adducts using 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrroline-N-oxyl (CmdeltaP) (a partition coefficient between octanol and water is approximately 3) as a spin-trapping agent. The resulting CmdeltaP-lipid alkyl radical adducts were determined by HPLC with postcolumn online thermal decomposition, in which the adducts were degraded into nitroxyl radicals by heating at 100 degrees C for 2 min. The resulting nitroxyl radicals were selectively and sensitively detected by electrochemical detection. With the present method, we, for the first time, determined the lipid alkyl radicals generated from linoleic acid, linolenic acid, and arachidonic acid via soybean lipoxygenase-1 or the radical initiator 2,2'-azobis(2,4-dimethyl-valeronitrile).
Collapse
Affiliation(s)
- Ichiro Koshiishi
- Nihon Pharmaceutical University, Ina-machi, Kita-Adachi-gun, Saitama 362-0806, Japan.
| | | | | | | |
Collapse
|