1
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Asma U, Bertotti ML, Zamai S, Arnold M, Amorati R, Scampicchio M. A Kinetic Approach to Oxygen Radical Absorbance Capacity (ORAC): Restoring Order to the Antioxidant Activity of Hydroxycinnamic Acids and Fruit Juices. Antioxidants (Basel) 2024; 13:222. [PMID: 38397820 PMCID: PMC10886186 DOI: 10.3390/antiox13020222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/26/2024] [Accepted: 02/02/2024] [Indexed: 02/25/2024] Open
Abstract
This study introduces a kinetic model that significantly improves the interpretation of the oxygen radical absorbance capacity (ORAC) assay. Our model accurately simulates and fits the bleaching kinetics of fluorescein in the presence of various antioxidants, achieving high correlation values (R2 > 0.99) with the experimental data. The fit to the experimental data is achieved by optimizing two rate constants, k5 and k6. The k5 value reflects the reactivity of antioxidants toward scavenging peroxyl radicals, whereas k6 measures the ability of antioxidants to regenerate oxidized fluorescein. These parameters (1) allow the detailed classification of cinnamic acids based on their structure-activity relationships, (2) provide insights into the interaction of alkoxyl radicals with fluorescein, and (3) account for the regeneration of fluorescein radicals by antioxidants. The application of the model to different antioxidants and fruit extracts reveals significant deviations from the results of traditional ORAC tests based on the area under the curve (AUC) approach. For example, lemon juice, rich in 'fast' antioxidants such as ascorbic acid, shows a high k5 value, in contrast to its low AUC values. This finding underscores the limitations of the AUC approach and highlights the advantages of our kinetic model in understanding antioxidative dynamics in food systems. This study presents a comprehensive, quantitative, mechanism-oriented approach to assessing antioxidant reactivity, demonstrating a significant improvement in ORAC assay applications.
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Affiliation(s)
- Umme Asma
- Faculty of Agricultural, Environment and Food Sciences, Free University of Bozen-Bolzano, Piazza Università 1, 39100 Bolzano, Italy; (U.A.); (S.Z.)
| | - Maria Letizia Bertotti
- Faculty of Engineering, Free University of Bozen-Bolzano, Piazza Università 1, 39100 Bolzano, Italy;
| | - Simone Zamai
- Faculty of Agricultural, Environment and Food Sciences, Free University of Bozen-Bolzano, Piazza Università 1, 39100 Bolzano, Italy; (U.A.); (S.Z.)
| | - Marcellus Arnold
- Department of Gastronomy Science and Functional Foods, Faculty of Food Science and Nutrition, Poznań University of Life Sciences, Wojska Polskiego 31, 60624 Poznań, Poland;
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”, University of Bologna, Via Gobetti 83, 40129 Bologna, Italy;
| | - Matteo Scampicchio
- Faculty of Agricultural, Environment and Food Sciences, Free University of Bozen-Bolzano, Piazza Università 1, 39100 Bolzano, Italy; (U.A.); (S.Z.)
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2
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Suhag R, Ferrentino G, Morozova K, Zatelli D, Scampicchio M, Amorati R. Antioxidant efficiency and oxidizability of mayonnaise by oximetry and isothermal calorimetry. Food Chem 2024; 433:137274. [PMID: 37666126 DOI: 10.1016/j.foodchem.2023.137274] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/06/2023]
Abstract
This study aimed to introduce a new method based on isothermal calorimetry (IC) for measuring the autoxidation rate in mayonnaise samples. Mayonnaise samples were prepared by homogenizing an aqueous phase, consisting of vinegar and egg yolk, with various oil phases, including sunflower, corn, extra virgin olive, grape seed, and apple seed oils at 60 °C. The rate of free radical formation (Ri) was controlled by adding AIBN (Ri = 4.4±0.1×10-9 M/s). The autoxidation rate determined by IC was highly correlated with the one measured using the oxygen uptake method (R2 = 0.99). The IC method accurately indicated the antioxidant capacity and rates of both inhibited and uninhibited periods, together with the oxidizability of mayonnaise samples. The mayonnaise made with extra virgin olive oil exhibited the lowest oxidizability, while sunflower oil showed maximum antioxidant efficiency. A significant advantage of the IC method was its ability to simultaneously measure up to 24 samples with minimal effort.
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Affiliation(s)
- Rajat Suhag
- Faculty of Agricultural, Environmental and Food Sciences, Free University of Bolzano, Piazza Università, 1, Bolzano 39100, Italy
| | - Giovanna Ferrentino
- Faculty of Agricultural, Environmental and Food Sciences, Free University of Bolzano, Piazza Università, 1, Bolzano 39100, Italy
| | - Ksenia Morozova
- Faculty of Agricultural, Environmental and Food Sciences, Free University of Bolzano, Piazza Università, 1, Bolzano 39100, Italy
| | | | - Matteo Scampicchio
- Faculty of Agricultural, Environmental and Food Sciences, Free University of Bolzano, Piazza Università, 1, Bolzano 39100, Italy.
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, Bologna I-40126, Italy
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3
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Amorati R, Guo Y, Budhlall BM, Barry CF, Cao D, Challa SSRK. Tandem Hydroperoxyl-Alkylperoxyl Radical Quenching by an Engineered Nanoporous Cerium Oxide Nanoparticle Macrostructure (NCeONP): Toward Efficient Solid-State Autoxidation Inhibitors. ACS Omega 2023; 8:40174-40183. [PMID: 37929124 PMCID: PMC10620910 DOI: 10.1021/acsomega.3c03654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 10/05/2023] [Indexed: 11/07/2023]
Abstract
The use of nanomaterials as inhibitors of the autoxidation of organic materials is attracting tremendous interest in petrochemistry, food storage, and biomedical applications. Metal oxide materials and CeO2 in particular represent one of the most investigated inorganic materials with promising radical trapping and antioxidant abilities. However, despite the importance, examples of the CeO2 material's ability to retard the autoxidation of organic substrates are still lacking, together with a plausible chemical mechanism for radical trapping. Herein, we report the synthesis of a new CeO2-derived nanoporous material (NCeONP) with excellent autoxidation inhibiting properties due to its ability to catalyze the cross-dismutation of alkyl peroxyl (ROO•) and hydroperoxyl (HOO•) radicals, generated in the system by the addition of the pro-aromatic hydrocarbon γ-terpinene. The antioxidant ability of NCeONP is superior to that of other nanosized metal oxides, including TiO2, ZnO, ZrO2, and pristine CeO2 nanoparticles. Studies of the reaction with a sacrificial reductant allowed us to propose a mechanism of inhibition consisting of H atom transfer from HOO• to the metal oxides (MOx + HOO• → MOx-H• + O2), followed by the release of the H atom to an ROO• radical (MOx-H• + ROO• → MOx + ROOH). Besides identifying NCeONP as a promising material for developing effective antioxidants, our study provides the first evidence of a radical mechanism that can be exploited to develop novel solid-state autoxidation inhibitors.
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Affiliation(s)
- Riccardo Amorati
- Department
of Chemistry “G. Ciamician”, University of Bologna, Via Gobetti 83, 40129 Bologna, Italy
| | - Yafang Guo
- Department
of Chemistry “G. Ciamician”, University of Bologna, Via Gobetti 83, 40129 Bologna, Italy
| | - Bridgette Maria Budhlall
- Department
of Plastics Engineering, University of Massachusetts
Lowell, Lowell, Massachusetts 01854, United States
| | - Carol Forance Barry
- Department
of Plastics Engineering, University of Massachusetts
Lowell, Lowell, Massachusetts 01854, United States
| | - Dongmei Cao
- Shared
Instrumentation Facility, Louisiana State
University, 121 Chemistry and Material Building, 4048 Highland Rd., Baton Rouge, Louisiana 70809, United States
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4
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Pincigher L, Valenti F, Bergamini C, Prata C, Fato R, Amorati R, Jin Z, Farruggia G, Fiorentini D, Calonghi N, Zalambani C. Myrcene: A Natural Compound Showing Anticancer Activity in HeLa Cells. Molecules 2023; 28:6728. [PMID: 37764505 PMCID: PMC10537210 DOI: 10.3390/molecules28186728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/14/2023] [Accepted: 09/17/2023] [Indexed: 09/29/2023] Open
Abstract
γ-terpinene, α-terpinene, p-cymene, and myrcene are monoterpenes found in many essential oils extracted from a variety of plants and spices. Myrcene also occurs naturally in plants such as hops, cannabis, lemongrass, and verbena and is used as a flavoring agent in food and beverage manufacturing. In this research, the biological efficacy of γ-terpinene, α-terpinene, p-cymene, and myrcene was studied in human cell lines (HeLa, SH-SY5Y, and HDFa). Cytotoxicity, cell proliferation, cell migration, and morphology assays were performed to obtain detailed information on the anticancer properties. Our results show that myrcene has potential biological activity, especially in HeLa cells. In this cell line, it leads to an arrest of proliferation, a decrease in motility and morphological changes with loss of sphericity and thickness, and DNA damage. In addition, the interaction of γ-terpinene, α-terpinene, p-terpinene, and myrcene with calf thymus DNA (ct-DNA) was studied by UV-visible spectrophotometry. DNA binding experiments show that only myrcene can interact with DNA with an apparent dissociation constant (Kd) of 29 × 10-6 M.
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Affiliation(s)
- Luca Pincigher
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (L.P.); (F.V.); (C.B.); (C.P.); (R.F.); (G.F.); (C.Z.)
| | - Francesca Valenti
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (L.P.); (F.V.); (C.B.); (C.P.); (R.F.); (G.F.); (C.Z.)
| | - Christian Bergamini
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (L.P.); (F.V.); (C.B.); (C.P.); (R.F.); (G.F.); (C.Z.)
| | - Cecilia Prata
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (L.P.); (F.V.); (C.B.); (C.P.); (R.F.); (G.F.); (C.Z.)
| | - Romana Fato
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (L.P.); (F.V.); (C.B.); (C.P.); (R.F.); (G.F.); (C.Z.)
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”, University of Bologna, Via Gobetti 83, 40129 Bologna, Italy; (R.A.); (Z.J.)
| | - Zongxin Jin
- Department of Chemistry “G. Ciamician”, University of Bologna, Via Gobetti 83, 40129 Bologna, Italy; (R.A.); (Z.J.)
| | - Giovanna Farruggia
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (L.P.); (F.V.); (C.B.); (C.P.); (R.F.); (G.F.); (C.Z.)
- National Institute of Biostructures and Biosystems, Via delle Medaglie d’Oro 305, 00136 Rome, Italy
| | - Diana Fiorentini
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (L.P.); (F.V.); (C.B.); (C.P.); (R.F.); (G.F.); (C.Z.)
| | - Natalia Calonghi
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (L.P.); (F.V.); (C.B.); (C.P.); (R.F.); (G.F.); (C.Z.)
| | - Chiara Zalambani
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (L.P.); (F.V.); (C.B.); (C.P.); (R.F.); (G.F.); (C.Z.)
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5
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Mavridi-Printezi A, Mollica F, Lucernati R, Montalti M, Amorati R. Insight into the Antioxidant Activity of 1,8-Dihydroxynaphthalene Allomelanin Nanoparticles. Antioxidants (Basel) 2023; 12:1511. [PMID: 37627506 PMCID: PMC10451768 DOI: 10.3390/antiox12081511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/27/2023] Open
Abstract
Melanins are stable and non-toxic pigments with great potential as chemopreventive agents against oxidative stress for medical and cosmetic applications. Allomelanin is a class of nitrogen-free melanin often found in fungi. The artificial allomelanin obtained by the polymerization of 1,8-dihydroxynaphthalene (DHN), poly-DHN (PDHN), has been recently indicated as a better radical quencher than polydopamine (PDA), a melanin model obtained by the polymerization of dopamine (DA); however, the chemical mechanisms underlying this difference are unclear. Here we investigate, by experimental and theoretical methods, the ability of PDHN nanoparticles (PDHN-NP), in comparison to PDA-NP, to trap alkylperoxyl (ROO•) and hydroperoxyl (HOO•) radicals that are involved in the propagation of peroxidation in real conditions. Our results demonstrate that PDHN-NP present a higher antioxidant efficiency with respect to PDA-NP against ROO• in water at pH 7.4 and against mixed ROO• and HOO• in acetonitrile, showing catalytic cross-termination activity. The antioxidant capacity of PDHN-NP in water is 0.8 mmol/g (ROO• radicals quenched by 1 g of PDHN-NP), with a rate constant of 3 × 105 M-1 s-1 for each reactive moiety. Quantum-mechanical calculations revealed that, thanks to the formation of a H-bond network, the quinones in PDHN-NP have a high affinity for H-atoms, thus justifying the high reactivity of PDHN-NP with HOO• observed experimentally.
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Affiliation(s)
| | | | | | - Marco Montalti
- Department of Chemistry “Giacomo Ciamician”, University of Bologna, Via Selmi 2, 40126 Bologna, Italy; (A.M.-P.); (F.M.)
| | - Riccardo Amorati
- Department of Chemistry “Giacomo Ciamician”, University of Bologna, Via Selmi 2, 40126 Bologna, Italy; (A.M.-P.); (F.M.)
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6
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de Sousa DP, Damasceno ROS, Amorati R, Elshabrawy HA, de Castro RD, Bezerra DP, Nunes VRV, Gomes RC, Lima TC. Essential Oils: Chemistry and Pharmacological Activities. Biomolecules 2023; 13:1144. [PMID: 37509180 PMCID: PMC10377445 DOI: 10.3390/biom13071144] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/03/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
In this review, we provide an overview of the current understanding of the main mechanisms of pharmacological action of essential oils and their components in various biological systems. A brief introduction on essential oil chemistry is presented to better understand the relationship of chemical aspects with the bioactivity of these products. Next, the antioxidant, anti-inflammatory, antitumor, and antimicrobial activities are discussed. The mechanisms of action against various types of viruses are also addressed. The data show that the multiplicity of pharmacological properties of essential oils occurs due to the chemical diversity in their composition and their ability to interfere with biological processes at cellular and multicellular levels via interaction with various biological targets. Therefore, these natural products can be a promising source for the development of new drugs.
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Affiliation(s)
- Damião P de Sousa
- Department of Pharmaceutical Sciences, Federal University of Paraiba, João Pessoa 58051-900, Brazil
| | - Renan Oliveira S Damasceno
- Department of Physiology and Pharmacology, Center of Biosciences, Federal University of Pernambuco, Recife 50670-901, Brazil
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via Gobetti 83, 40129 Bologna, Italy
| | - Hatem A Elshabrawy
- Department of Molecular and Cellular Biology, College of Osteopathic Medicine, Sam Houston State University, Conroe, TX 77304, USA
| | - Ricardo D de Castro
- Department of Clinical and Social Dentistry, Federal University of Paraíba, João Pessoa 58051-970, Brazil
| | - Daniel P Bezerra
- Instituto Gonçalo Moniz, Fundação Oswaldo Cruz (IGM-FIOCRUZ/BA), Salvador 40296-710, Brazil
| | - Vitória Regina V Nunes
- Department of Pharmaceutical Sciences, Federal University of Paraiba, João Pessoa 58051-900, Brazil
| | - Rebeca C Gomes
- Department of Pharmaceutical Sciences, Federal University of Paraiba, João Pessoa 58051-900, Brazil
| | - Tamires C Lima
- Department of Pharmacy, Federal University of Sergipe, São Cristóvão 49100-000, Brazil
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7
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Baschieri A, Jin Z, Amorati R. Hydroperoxyl Radical (HOO •) as a reducing agent: unexpected synergy with antioxidants. A review. Free Radic Res 2023:1-15. [PMID: 37158401 DOI: 10.1080/10715762.2023.2212121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
This review highlights the progress made in recent years in harnessing the peculiar chemistry of the hydroperoxyl, or perhydroxyl, radical (HOO•) during lipid peroxidation, particularly with regard to its interaction with antioxidants. The HOO• radical, the protonated form of superoxide, plays an important role in the propagation and termination of lipid peroxidation in nonaqueous systems. However, differently from alkylperoxyl (ROO•) radicals that have only oxidizing ability, HOO• has a two-faced oxidizing and reducing activity. The HOO• radical can reduce the radical of the antioxidant (phenols and aromatic amines) by H-atom transfer (A• + HOO• ⟶ AH + O2) thus increasing the length of the inhibition period and the effectiveness of the antioxidant. The simultaneous presence of HOO• and ROO• radicals triggers the catalytic antioxidant activity of quinones and nitroxides, and explains the antioxidant activity of melanin-like polymers. The HOO• radical can be formed by fragmentation of ROO• radicals deriving from amines, alcohols, substituted alkenes and may be present at low concentrations in many oxidizing systems. Pro-aromatic compounds, like the natural essential oil component γ-terpinene, are the most effective sources of HOO•, and behave as co-antioxidants in the presence of nitroxides or quinones. The future developments and applications of the HOO• chemistry in the context of the inhibition of autoxidation are also discussed.
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Affiliation(s)
- Andrea Baschieri
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Via P. Gobetti 101, I-40129 Bologna, Italy
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
| | - Zongxin Jin
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Via P. Gobetti 101, I-40129 Bologna, Italy
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
| | - Riccardo Amorati
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Via P. Gobetti 101, I-40129 Bologna, Italy
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
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8
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Mavridi-Printezi A, Menichetti A, Mordini D, Amorati R, Montalti M. Recent Applications of Melanin-like Nanoparticles as Antioxidant Agents. Antioxidants (Basel) 2023; 12:antiox12040863. [PMID: 37107238 PMCID: PMC10135245 DOI: 10.3390/antiox12040863] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/24/2023] [Accepted: 03/29/2023] [Indexed: 04/05/2023] Open
Abstract
Nanosized antioxidants are highly advantageous in terms of versatility and pharmacokinetics, with respect to conventional molecular ones. Melanin-like materials, artificial species inspired by natural melanin, combine recognized antioxidant (AOX) activity with a unique versatility of preparation and modification. Due to this versatility and documented biocompatibility, artificial melanin has been incorporated into a variety of nanoparticles (NP) in order to give new platforms for nanomedicine with enhanced AOX activity. In this review article, we first discuss the chemical mechanisms behind the AOX activity of materials in the context of the inhibition of the radical chain reaction responsible for the peroxidation of biomolecules. We also focus briefly on the AOX properties of melanin-like NP, considering the effect of parameters such as size, preparation methods and surface functionalization on them. Then, we consider the most recent and relevant applications of AOX melanin-like NPs that are able to counteract ferroptosis and be involved in the treatment of important diseases that affect, e.g., the cardiovascular and nervous systems, as well as the kidneys, liver and articulations. A specific section will be dedicated to cancer treatment, since the role of melanin in this context is still very debated. Finally, we propose future strategies in AOX development for a better chemical understanding of melanin-like materials. In particular, the composition and structure of these materials are still debated, and they present a high level of variability. Thus, a better understanding of the mechanism behind the interaction of melanin-like nanostructures with different radicals and highly reactive species would be highly advantageous for the design of more effective and specific AOX nano-agents.
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Affiliation(s)
| | - Arianna Menichetti
- Department of Chemistry «Giacomo Ciamician», University of Bologna, Via Selmi 2, 40126 Bologna, Italy
| | - Dario Mordini
- Department of Chemistry «Giacomo Ciamician», University of Bologna, Via Selmi 2, 40126 Bologna, Italy
| | - Riccardo Amorati
- Department of Chemistry «Giacomo Ciamician», University of Bologna, Via Selmi 2, 40126 Bologna, Italy
| | - Marco Montalti
- Department of Chemistry «Giacomo Ciamician», University of Bologna, Via Selmi 2, 40126 Bologna, Italy
- Tecnopolo di Rimini, Via Dario Campana 71, 47921 Rimini, Italy
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9
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Cardullo N, Monti F, Muccilli V, Amorati R, Baschieri A. Reaction with ROO• and HOO• Radicals of Honokiol-Related Neolignan Antioxidants. Molecules 2023; 28:molecules28020735. [PMID: 36677790 PMCID: PMC9867055 DOI: 10.3390/molecules28020735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/05/2023] [Accepted: 01/07/2023] [Indexed: 01/15/2023]
Abstract
Honokiol is a natural bisphenol neolignan present in the bark of Magnolia officinalis, whose extracts have been employed in oriental medicine to treat several disorders, showing a variety of biological properties, including antitumor activity, potentially related to radical scavenging. Six bisphenol neolignans with structural motifs related to the natural bioactive honokiol were synthesized. Their chain-breaking antioxidant activity was evaluated in the presence of peroxyl (ROO•) and hydroperoxyl (HOO•) radicals by both experimental and computational methods. Depending on the number and position of the hydroxyl and alkyl groups present on the molecules, these derivatives are more or less effective than the reference natural compound. The rate constant of the reaction with ROO• radicals for compound 7 is two orders of magnitude greater than that of honokiol. Moreover, for compounds displaying quinonic oxidized forms, we demonstrate that the addition of 1,4 cyclohexadiene, able to generate HOO• radicals, restores their antioxidant activity, because of the reducing capability of the HOO• radicals. The antioxidant activity of the oxidized compounds in combination with 1,4-cyclohexadiene is, in some cases, greater than that found for the starting compounds towards the peroxyl radicals. This synergy can be applied to maximize the performances of these new bisphenol neolignans.
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Affiliation(s)
- Nunzio Cardullo
- Dipartimento di Scienze Chimiche, Università di Catania, V.le A. Doria 6, 95125 Catania, Italy
| | - Filippo Monti
- Istituto per la Sintesi Organica e la Fotoreattività (ISOF), Consiglio Nazionale delle Ricerche (CNR), Via Gobetti 101, 40129 Bologna, Italy
| | - Vera Muccilli
- Dipartimento di Scienze Chimiche, Università di Catania, V.le A. Doria 6, 95125 Catania, Italy
| | - Riccardo Amorati
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
- Correspondence: (R.A.); (A.B.)
| | - Andrea Baschieri
- Istituto per la Sintesi Organica e la Fotoreattività (ISOF), Consiglio Nazionale delle Ricerche (CNR), Via Gobetti 101, 40129 Bologna, Italy
- Correspondence: (R.A.); (A.B.)
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10
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Mollica F, Bonoldi L, Amorati R. Kinetic Analysis of High-Temperature Sunflower Oil Peroxidation Inhibited by the Major Families of Phenolic Antioxidants Unveils the Extraordinary Activity of 1,4-Hydroquinones. Antioxidants (Basel) 2022; 11:2142. [PMID: 36358514 PMCID: PMC9686879 DOI: 10.3390/antiox11112142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/27/2022] [Accepted: 10/27/2022] [Indexed: 10/12/2023] Open
Abstract
Peroxidation of vegetable oils represents a major problem for the food and biodiesel industries, and it is greatly accelerated by oil degree of unsaturation and by temperature increase. Phenols represent the most common additives used to counteract oil peroxidation, however clear structure-activity relationships at high temperatures are not available. We report, herein, a kinetic study of O2 consumption during spontaneous peroxidation of sunflower oil at 130 °C in the presence of 18 antioxidants belonging to the main families of natural and synthetic phenols, including α-tocopherol, alkylphenols (BHT, BHA), hydroquinones (TBHD), catechols (quercetin, catechin) and gallates. Results show that TBHQ provide the best protection in terms of induction period (IP) duration and O2 consumption rate. EPR spectroscopy demonstrated that the inhibition activity is negatively correlated to the stability of the phenoxyl radical of the antioxidant (A•), suggesting that chain propagation with linoleate (RH) moieties A• + RH → AH + R• decreases the efficacy of those antioxidants forming persistent A• radicals. These results provide important information to optimize the antioxidant activity of phenols and of novel phenol-based materials.
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Affiliation(s)
- Fabio Mollica
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, I-40126 Bologna, Italy
| | - Lucia Bonoldi
- Research and Technological Innovation Department, Eni SpA, Via F. Maritano 26, I-20097 San Donato Milanese, Italy
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, I-40126 Bologna, Italy
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11
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Scurti S, Caretti D, Mollica F, Di Antonio E, Amorati R. Chain-Breaking Antioxidant and Peroxyl Radical Trapping Activity of Phenol-Coated Magnetic Iron Oxide Nanoparticles. Antioxidants (Basel) 2022; 11:antiox11061163. [PMID: 35740061 PMCID: PMC9219998 DOI: 10.3390/antiox11061163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 11/18/2022] Open
Abstract
Superparamagnetic iron oxide nanoparticles (SPION) are important materials for biomedical applications, and phenol capping is a common procedure to passivate their surface. As phenol capped SPION have been reported to behave as antioxidants, herein, we investigate the mechanism underlying this activity by studying the reaction with alkyl peroxyl (ROO•) radicals. SPION were prepared by coprecipitation of Fe(II) and Fe(III), using phenolic antioxidants (gallic acid, Trolox and nordihydroguaiaretic acid) as post-synthesis capping agents and by different purification procedures. The reactivity of ROO• was investigated by inhibited autoxidation studies, using styrene as an oxidizable substrate (solvent MeCN, 30 °C) and azo-bis(isobutyronitrile) as a radical initiator. While unprotected, bare SPION behaved as prooxidant, accelerating the O2 consumption of styrene autoxidation, phenol capping provided a variable antioxidant effect that was dependent upon the purification degree of the material. Thoroughly washed SPION, containing from 7% to 14% (w/w) of phenols, had a low reactivity toward peroxyl radicals, while SPION with a higher phenol content (46% to 55%) showed a strong radical trapping activity. Our results indicate that the antioxidant activity of phenol-capped SPION can be caused by its release in a solution of weakly bound phenols, and that purification plays a major role in determining the properties of these materials.
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Affiliation(s)
- Stefano Scurti
- Department of Industrial Chemistry “Toso Montanari”, University of Bologna, UdR INSTM of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy; (S.S.); (D.C.)
| | - Daniele Caretti
- Department of Industrial Chemistry “Toso Montanari”, University of Bologna, UdR INSTM of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy; (S.S.); (D.C.)
| | - Fabio Mollica
- Department of Chemistry “G. Ciamician”, University of Bologna, Via San Giacomo 11, 40126 Bologna, Italy; (F.M.); (E.D.A.)
| | - Erika Di Antonio
- Department of Chemistry “G. Ciamician”, University of Bologna, Via San Giacomo 11, 40126 Bologna, Italy; (F.M.); (E.D.A.)
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”, University of Bologna, Via San Giacomo 11, 40126 Bologna, Italy; (F.M.); (E.D.A.)
- Correspondence:
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12
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Alfieri ML, Panzella L, Amorati R, Cariola A, Valgimigli L, Napolitano A. Role of Sulphur and Heavier Chalcogens on the Antioxidant Power and Bioactivity of Natural Phenolic Compounds. Biomolecules 2022; 12:90. [PMID: 35053239 PMCID: PMC8774257 DOI: 10.3390/biom12010090] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 02/06/2023] Open
Abstract
The activity of natural phenols is primarily associated to their antioxidant potential, but is ultimately expressed in a variety of biological effects. Molecular scaffold manipulation of this large variety of compounds is a currently pursued approach to boost or modulate their properties. Insertion of S/Se/Te containing substituents on phenols may increase/decrease their H-donor/acceptor ability by electronic and stereo-electronic effects related to the site of substitution and geometrical constrains. Oxygen to sulphur/selenium isosteric replacement in resveratrol or ferulic acid leads to an increase in the radical scavenging activity with respect to the parent phenol. Several chalcogen-substituted phenols inspired by Vitamin E and flavonoids have been prepared, which in some cases prove to be chain-breaking antioxidants, far better than the natural counterparts. Conjugation of catechols with biological thiols (cysteine, glutathione, dihydrolipoic acid) is easily achieved by addition to the corresponding ortho-quinones. Noticeable examples of compounds with potentiated antioxidant activities are the human metabolite 5-S-cysteinyldopa, with high iron-induced lipid peroxidation inhibitory activity, due to strong iron (III) binding, 5-S-glutathionylpiceatannol a most effective inhibitor of nitrosation processes, and 5-S-lipoylhydroxytyrosol, and its polysulfides that proved valuable oxidative-stress protective agents in various cellular models. Different methodologies have been used for evaluation of the antioxidant power of these compounds against the parent compounds. These include kinetics of inhibition of lipid peroxidation alkylperoxyl radicals, common chemical assays of radical scavenging, inhibition of the OH• mediated hydroxylation/oxidation of model systems, ferric- or copper-reducing power, scavenging of nitrosating species. In addition, computational methods allowed researchers to determine the Bond Dissociation Enthalpy values of the OH groups of chalcogen modified phenolics and predict the best performing derivative. Finally, the activity of Se and Te containing compounds as mimic of glutathione peroxidase has been evaluated, together with other biological activities including anticancer action and (neuro)protective effects in various cellular models. These and other achievements are discussed and rationalized to guide future development in the field.
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Affiliation(s)
- Maria Laura Alfieri
- Department of Chemical Sciences, University of Naples “Federico II”, Via Cintia 21, I-80126 Naples, Italy; (M.L.A.); (L.P.)
| | - Lucia Panzella
- Department of Chemical Sciences, University of Naples “Federico II”, Via Cintia 21, I-80126 Naples, Italy; (M.L.A.); (L.P.)
| | - Riccardo Amorati
- Department of Chemistry “Giacomo Ciamician”, University of Bologna, Via S. Giacomo 11, I-40126 Bologna, Italy; (R.A.); (A.C.)
| | - Alice Cariola
- Department of Chemistry “Giacomo Ciamician”, University of Bologna, Via S. Giacomo 11, I-40126 Bologna, Italy; (R.A.); (A.C.)
| | - Luca Valgimigli
- Department of Chemistry “Giacomo Ciamician”, University of Bologna, Via S. Giacomo 11, I-40126 Bologna, Italy; (R.A.); (A.C.)
| | - Alessandra Napolitano
- Department of Chemical Sciences, University of Naples “Federico II”, Via Cintia 21, I-80126 Naples, Italy; (M.L.A.); (L.P.)
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13
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Abstract
Polydopamine (PDA) materials are important due to their unique physicochemical properties and their potential as chemopreventive agents for diseases connected with oxidative stress. Although PDA has been suggested to display antioxidant activity, its efficacy is controversial and its mechanism of action is still unclear. Herein, we report that accurately purified PDA nanoparticles in water at pH 7.4 are unable to quench alkylperoxyls (ROO˙), which are the radicals responsible for the propagation of lipid peroxidation, despite PDA reacting with the model DPPH˙ and ABTS˙+ radicals. PDA nanoparticles prepared by copolymerization of dopamine with the dialkyl nitroxide 4-NH2TEMPO show instead good antioxidant activity, thanks to the ROO˙ trapping ability of the nitroxide. Theoretical calculations performed on a quinone-catechol dimer, reproducing the structural motive of PDA, indicate a reactivity with ROO˙ similar to catechol. These results suggest that PDA nanoparticles have an "onion-like" structure, with a catechol-rich core, which can be reached only by DPPH˙ and ABTS˙+, and a surface mainly represented by quinones. The importance of assessing the antioxidant activity by inhibited autoxidation studies is also discussed.
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Affiliation(s)
- Fabio Mollica
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy.
| | - Rosa Lucernati
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy.
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy.
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14
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Baschieri A, Amorati R. Methods to Determine Chain-Breaking Antioxidant Activity of Nanomaterials beyond DPPH •. A Review. Antioxidants (Basel) 2021; 10:1551. [PMID: 34679687 PMCID: PMC8533328 DOI: 10.3390/antiox10101551] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 12/15/2022] Open
Abstract
This review highlights the progress made in recent years in understanding the mechanism of action of nanomaterials with antioxidant activity and in the chemical methods used to evaluate their activity. Nanomaterials represent one of the most recent frontiers in the research for improved antioxidants, but further development is hampered by a poor characterization of the ''antioxidant activity'' property and by using oversimplified chemical methods. Inhibited autoxidation experiments provide valuable information about the interaction with the most important radicals involved in the lipid oxidation, namely alkylperoxyl and hydroperoxyl radicals, and demonstrate unambiguously the ability to stop the oxidation of organic materials. It is proposed that autoxidation methods should always complement (and possibly replace) the use of assays based on the quenching of stable radicals (such as DPPH• and ABTS•+). The mechanisms leading to the inhibition of the autoxidation (sacrificial and catalytic radical trapping antioxidant activity) are described in the context of nanoantioxidants. Guidelines for the selection of the appropriate testing conditions and of meaningful kinetic analysis are also given.
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Affiliation(s)
- Andrea Baschieri
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche (ISOF-CNR), Via P. Gobetti 101, 40129 Bologna, Italy;
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
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15
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Guo Y, Pizzol R, Gabbanini S, Baschieri A, Amorati R, Valgimigli L. Absolute Antioxidant Activity of Five Phenol-Rich Essential Oils. Molecules 2021; 26:molecules26175237. [PMID: 34500670 PMCID: PMC8434318 DOI: 10.3390/molecules26175237] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 12/29/2022] Open
Abstract
Essential oils (EOs) have promising antioxidant activities which are gaining interest as natural alternatives to synthetic antioxidants in the food and cosmetic industries. However, quantitative data on chain-breaking activity and on the kinetics of peroxyl radical trapping are missing. Five phenol-rich EOs were analyzed by GC-MS and studied by oxygen-uptake kinetics in inhibited controlled autoxidations of reference substrates (cumene and squalene). Terpene-rich Thymus vulgaris (thymol 4%; carvacrol 33.9%), Origanum vulgare, (thymol 0.4%; carvacrol 66.2%) and Satureja hortensis, (thymol 1.7%; carvacrol 46.6%), had apparent kinh (30 °C, PhCl) of (1.5 ± 0.3) × 104, (1.3 ± 0.1) × 104 and (1.1 ± 0.3) × 104 M−1s−1, respectively, while phenylpropanoid-rich Eugenia caryophyllus (eugenol 80.8%) and Cinnamomum zeylanicum, (eugenol 81.4%) showed apparent kinh (30 °C, PhCl) of (5.0 ± 0.1) × 103 and (4.9 ± 0.3) × 103 M−1s−1, respectively. All EOs already granted good antioxidant protection of cumene at a concentration of 1 ppm (1 mg/L), the duration being proportional to their phenolic content, which dictated their antioxidant behavior. They also afforded excellent protection of squalene after adjusting their concentration (100 mg/L) to account for the much higher oxidizability of this substrate. All investigated EOs had kinh comparable to synthetic butylated hydroxytoluene (BHT) were are eligible to replace it in the protection of food or cosmetic products.
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Affiliation(s)
- Yafang Guo
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy; (Y.G.); (R.P.); (R.A.)
| | - Romeo Pizzol
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy; (Y.G.); (R.P.); (R.A.)
| | - Simone Gabbanini
- Research & Development—BeC s.r.l., Via C. Monteverdi 49, 47122 Forlì, Italy;
| | - Andrea Baschieri
- The Institute of Organic Synthesis and Photoreactivity, Consiglio Nazionale delle Ricerche (CNR), Via P. Gobetti 101, 40129 Bologna, Italy;
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy; (Y.G.); (R.P.); (R.A.)
| | - Luca Valgimigli
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy; (Y.G.); (R.P.); (R.A.)
- Correspondence: ; Tel.: +39-051-2095683
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16
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Amorati R, Valgimigli L, Baschieri A, Guo Y, Mollica F, Menichetti S, Lupi M, Viglianisi C. SET and HAT/PCET acid-mediated oxidation processes in helical shaped fused bis-phenothiazines. Chemphyschem 2021; 22:1446-1454. [PMID: 34033195 PMCID: PMC8361695 DOI: 10.1002/cphc.202100387] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Indexed: 12/21/2022]
Abstract
Helical shaped fused bis-phenothiazines 1-9 have been prepared and their red-ox behaviour quantitatively studied. Helicene radical cations (Hel.+ ) can be obtained either by UV-irradiation in the presence of PhCl or by chemical oxidation. The latter process is extremely sensitive to the presence of acids in the medium with molecular oxygen becoming a good single electron transfer (SET) oxidant. The reaction of hydroxy substituted helicenes 5-9 with peroxyl radicals (ROO. ) occurs with a 'classical' HAT process giving HelO. radicals with kinetics depending upon the substitution pattern of the aromatic rings. In the presence of acetic acid, a fast medium-promoted proton-coupled electron transfer (PCET) process takes place with formation of HelO. radicals possibly also via a helicene radical cation intermediate. Remarkably, also helicenes 1-4, lacking phenoxyl groups, in the presence of acetic acid react with peroxyl radicals through a medium-promoted PCET mechanism with formation of the radical cations Hel.+ . Along with the synthesis, EPR studies of radicals and radical cations, BDE of Hel-OH group (BDEOH ), and kinetic constants (kinh ) of the reactions with ROO. species of helicenes 1-9 have been measured and calculated to afford a complete rationalization of the redox behaviour of these appealing chiral compounds.
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Affiliation(s)
- Riccardo Amorati
- Department of Chemistry “G. Ciamician”University of BolognaVia S. Giacomo 1140126BolognaItaly
| | - Luca Valgimigli
- Department of Chemistry “G. Ciamician”University of BolognaVia S. Giacomo 1140126BolognaItaly
| | - Andrea Baschieri
- Department of Chemistry “G. Ciamician”University of BolognaVia S. Giacomo 1140126BolognaItaly
| | - Yafang Guo
- Department of Chemistry “G. Ciamician”University of BolognaVia S. Giacomo 1140126BolognaItaly
| | - Fabio Mollica
- Department of Chemistry “G. Ciamician”University of BolognaVia S. Giacomo 1140126BolognaItaly
| | - Stefano Menichetti
- Department of Chemistry “U. Schiff”University of FlorenceVia Della Lastruccia 3–13, Sesto Fiorentino50019FirenzeItaly
| | - Michela Lupi
- Department of Chemistry “U. Schiff”University of FlorenceVia Della Lastruccia 3–13, Sesto Fiorentino50019FirenzeItaly
| | - Caterina Viglianisi
- Department of Chemistry “U. Schiff”University of FlorenceVia Della Lastruccia 3–13, Sesto Fiorentino50019FirenzeItaly
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17
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Genovese D, Baschieri A, Vona D, Baboi RE, Mollica F, Prodi L, Amorati R, Zaccheroni N. Nitroxides as Building Blocks for Nanoantioxidants. ACS Appl Mater Interfaces 2021; 13:31996-32004. [PMID: 34156238 PMCID: PMC8289242 DOI: 10.1021/acsami.1c06674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Nitroxides are an important class of radical trapping antioxidants whose promising biological activities are connected to their ability to scavenge peroxyl (ROO•) radicals. We have measured the rate constants of the reaction with ROO• (kinh) for a series of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) derivatives as 5.1 × 106, 1.1 × 106, 5.4 × 105, 3.7 × 105, 1.1 × 105, 1.9 × 105, and 5.6 × 104 M-1 s-1 for -H, -OH, -NH2, -COOH, -NHCOCH3, -CONH(CH2)3CH3, and ═O substituents in the 4 position, with a good Marcus relationship between log (kinh) and E° for the R2NO•/R2NO+ couple. Newly synthesized Pluronic-silica nanoparticles (PluS) having nitroxide moieties covalently bound to the silica surface (PluS-NO) through a TEMPO-CONH-R link and coumarin dyes embedded in the silica core, has kinh = 1.5 × 105 M-1 s-1. Each PluS-bound nitroxide displays an inhibition duration nearly double that of a structurally related "free" nitroxide. As each PluS-NO particle bears an average of 30 nitroxide units, this yields an overall ≈60-fold larger inhibition of the PluS-NO nanoantioxidant compared to the molecular analogue. The implications of these results for the development of novel nanoantioxidants based on nitroxide derivatives are discussed, such as the choice of the best linkage group and the importance of the regeneration cycle in determining the duration of inhibition.
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Affiliation(s)
- Damiano Genovese
- Department
of Chemistry “Giacomo Ciamician”, University of Bologna, via Selmi 2, 40126 Bologna, Italy
| | - Andrea Baschieri
- Istituto
per la Sintesi Organica e la Fotoreattività (ISOF), Consiglio Nazionale delle Ricerche (CNR), via Gobetti 101, 40129 Bologna, Italy
| | - Danilo Vona
- Department
of Chemistry, University of Bari, via Orabona 4, I-70126 Bari, Italy
| | - Ruxandra Elena Baboi
- Department
of Chemistry “Giacomo Ciamician”, University of Bologna, via San Giacomo 11, 40126 Bologna, Italy
| | - Fabio Mollica
- Department
of Chemistry “Giacomo Ciamician”, University of Bologna, via San Giacomo 11, 40126 Bologna, Italy
| | - Luca Prodi
- Department
of Chemistry “Giacomo Ciamician”, University of Bologna, via Selmi 2, 40126 Bologna, Italy
| | - Riccardo Amorati
- Department
of Chemistry “Giacomo Ciamician”, University of Bologna, via San Giacomo 11, 40126 Bologna, Italy
| | - Nelsi Zaccheroni
- Department
of Chemistry “Giacomo Ciamician”, University of Bologna, via Selmi 2, 40126 Bologna, Italy
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18
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Guo Y, Baschieri A, Mollica F, Valgimigli L, Cedrowski J, Litwinienko G, Amorati R. Hydrogen Atom Transfer from HOO . to ortho-Quinones Explains the Antioxidant Activity of Polydopamine. Angew Chem Int Ed Engl 2021; 60:15220-15224. [PMID: 33876878 PMCID: PMC8362028 DOI: 10.1002/anie.202101033] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/09/2021] [Indexed: 12/24/2022]
Abstract
Melanins are stable and non-toxic biomaterials with a great potential as chemopreventive agents for diseases connected with oxidative stress, but the mechanism of their antioxidant action is unclear. Herein, we show that polydopamine (PDA), a well-known synthetic melanin, becomes an excellent trap for alkylperoxyl radicals (ROO. , typically formed during autoxidation of lipid substrates) in the presence of hydroperoxyl radicals (HOO. ). The key reaction explaining this peculiar antioxidant activity is the reduction of the ortho-quinone moieties present in PDA by the reaction with HOO. . This reaction occurs via a H-atom transfer mechanism, as demonstrated by the large kinetic solvent effect of the reaction of a model quinone (3,5-di-tert-butyl-1,2-benzoquinone) with HOO. (k=1.5×107 and 1.1×105 M-1 s-1 in PhCl and MeCN). The chemistry disclosed herein is an important step to rationalize the redox-mediated bioactivity of melanins and of quinones.
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Affiliation(s)
- Yafang Guo
- Department of Chemistry “G. Ciamician”University of BolognaVia S. Giacomo 1140126BolognaItaly
| | - Andrea Baschieri
- Department of Chemistry “G. Ciamician”University of BolognaVia S. Giacomo 1140126BolognaItaly
| | - Fabio Mollica
- Department of Chemistry “G. Ciamician”University of BolognaVia S. Giacomo 1140126BolognaItaly
| | - Luca Valgimigli
- Department of Chemistry “G. Ciamician”University of BolognaVia S. Giacomo 1140126BolognaItaly
| | - Jakub Cedrowski
- Faculty of ChemistryUniversity of WarsawPasteura 102-093WarsawPoland
| | | | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”University of BolognaVia S. Giacomo 1140126BolognaItaly
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19
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Guo Y, Baschieri A, Mollica F, Valgimigli L, Cedrowski J, Litwinienko G, Amorati R. Hydrogen Atom Transfer from HOO
.
to
ortho
‐Quinones Explains the Antioxidant Activity of Polydopamine. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Yafang Guo
- Department of Chemistry “G. Ciamician” University of Bologna Via S. Giacomo 11 40126 Bologna Italy
| | - Andrea Baschieri
- Department of Chemistry “G. Ciamician” University of Bologna Via S. Giacomo 11 40126 Bologna Italy
| | - Fabio Mollica
- Department of Chemistry “G. Ciamician” University of Bologna Via S. Giacomo 11 40126 Bologna Italy
| | - Luca Valgimigli
- Department of Chemistry “G. Ciamician” University of Bologna Via S. Giacomo 11 40126 Bologna Italy
| | - Jakub Cedrowski
- Faculty of Chemistry University of Warsaw Pasteura 1 02-093 Warsaw Poland
| | | | - Riccardo Amorati
- Department of Chemistry “G. Ciamician” University of Bologna Via S. Giacomo 11 40126 Bologna Italy
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20
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Guo Y, Baschieri A, Amorati R, Valgimigli L. Synergic antioxidant activity of γ-terpinene with phenols and polyphenols enabled by hydroperoxyl radicals. Food Chem 2020; 345:128468. [PMID: 33341300 DOI: 10.1016/j.foodchem.2020.128468] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 01/09/2023]
Abstract
Antioxidant interactions of γ-terpinene with α-tocopherol mimic 2,2,5,7,8-pentamethyl-6-chromanol (PMHC) and caffeic acid phenethyl ester (CAPE), used as models, respectively, of mono- and poly-phenols were demonstrated by differential oximetry during the inhibited autoxidation of model substrates: stripped sunflower oil, squalene, and styrene. With all substrates, γ-terpinene acts synergistically regenerating the chain-breaking antioxidants PMHC and CAPE from their radicals, via the formation of hydroperoxyl radicals. The inhibition duration for mixtures PMHC/γ-terpinene and CAPE/γ-terpinene increased with γ-terpinene concentration, while rate constants for radical-trapping were unchanged by γ-terpinene, being 3.1 × 106 and 4.8 × 105 M-1s-1 for PMHC and CAPE in chlorobenzene (30 °C). Using 3,5-di-tert-butylcatechol and 3,5-di-tert-butyl-1,2-bezoquinone we demonstrate that γ-terpinene can reduce quinones to catechols enabling their antioxidant activity. The different synergy mechanism of γ-terpinene with mono- and poly-phenolic antioxidants is discussed and its relevance is proven in homogenous lipids using natural α-tocopherol and hydroxytyrosol as antioxidants, calling for further studies in heterogenous food products.
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Affiliation(s)
- Yafang Guo
- University of Bologna, Department of Chemistry "G. Ciamician", Via S. Giacomo 11, 40126 Bologna, Italy
| | - Andrea Baschieri
- University of Bologna, Department of Chemistry "G. Ciamician", Via S. Giacomo 11, 40126 Bologna, Italy
| | - Riccardo Amorati
- University of Bologna, Department of Chemistry "G. Ciamician", Via S. Giacomo 11, 40126 Bologna, Italy
| | - Luca Valgimigli
- University of Bologna, Department of Chemistry "G. Ciamician", Via S. Giacomo 11, 40126 Bologna, Italy.
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21
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Valgimigli L, Alfieri ML, Amorati R, Baschieri A, Crescenzi O, Napolitano A, d'Ischia M. Proton-Sensitive Free-Radical Dimer Evolution Is a Critical Control Point for the Synthesis of Δ 2,2'-Bibenzothiazines. J Org Chem 2020; 85:11440-11448. [PMID: 32842740 PMCID: PMC8011920 DOI: 10.1021/acs.joc.0c01520] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The mechanism of the acid-dependent
interring dehydrogenation in
the conversion of the single-bonded 3-phenyl-2H-1,4-benzothiazine
dimer 2 to the Δ2,2′-bi(2H-1,4-benzothiazine) scaffold of red hair pigments
is disclosed herein. Integrated chemical oxidation and oxygen consumption
experiments, coupled with electron paramagnetic resonance (EPR) analyses
and DFT calculations, allowed the identification of a key diprotonated
free-radical intermediate, which was implicated in a remarkable oxygen-dependent
chain process via peroxyl radical formation and evolution to give
the Δ2,2′-bi(2H-1,4-benzothiazine) dimer 3 by interring dehydrogenation.
The critical requirement for strongly acidic conditions was rationalized
for the first time by the differential evolution channels of isomeric
peroxyl radical intermediates at the 2- versus 3-positions. These
results offer for the first time a rationale to expand the synthetic
scope of the double interring dehydrogenation pathway for the preparation
of novel symmetric double-bond bridged captodative heterocycles.
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Affiliation(s)
- Luca Valgimigli
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Bologna I-40126, Italy
| | - Maria Laura Alfieri
- Department of Chemical Sciences, University of Naples Federico II, Naples I-80126, Italy
| | - Riccardo Amorati
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Bologna I-40126, Italy
| | - Andrea Baschieri
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Bologna I-40126, Italy
| | - Orlando Crescenzi
- Department of Chemical Sciences, University of Naples Federico II, Naples I-80126, Italy
| | - Alessandra Napolitano
- Department of Chemical Sciences, University of Naples Federico II, Naples I-80126, Italy
| | - Marco d'Ischia
- Department of Chemical Sciences, University of Naples Federico II, Naples I-80126, Italy
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Viglianisi C, Scarlini A, Tofani L, Menichetti S, Baschieri A, Amorati R. Magnetic nanoantioxidants with improved radical-trapping stoichiometry as stabilizers for inhibition of peroxide formation in ethereal solvents. Sci Rep 2019; 9:17219. [PMID: 31748620 PMCID: PMC6868006 DOI: 10.1038/s41598-019-53531-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 10/31/2019] [Indexed: 01/22/2023] Open
Abstract
Graphite-coated magnetic cobalt nanoparticles (CoNPs) decorated with hindered phenolic antioxidant analogues of 2,6-di-tert-butyl-4-methylphenol (BHT, E321) provided easily removable nanoantioxidants capable of preventing the autoxidation of organic solvents as tetrahydrofuran (THF).
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Affiliation(s)
- Caterina Viglianisi
- Department of Chemistry "U. Schiff", University of Florence, Via della Lastruccia 3-13, 50019, Sesto Fiorentino, Firenze, Italy.
| | - Alessia Scarlini
- Department of Chemistry "U. Schiff", University of Florence, Via della Lastruccia 3-13, 50019, Sesto Fiorentino, Firenze, Italy
| | - Lorenzo Tofani
- Department of Chemistry "U. Schiff", University of Florence, Via della Lastruccia 3-13, 50019, Sesto Fiorentino, Firenze, Italy
| | - Stefano Menichetti
- Department of Chemistry "U. Schiff", University of Florence, Via della Lastruccia 3-13, 50019, Sesto Fiorentino, Firenze, Italy
| | - Andrea Baschieri
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy
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23
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Fontana A, Guernelli S, Di Crescenzo A, Di Profio P, Palomba F, De Crescentini L, Baschieri A, Amorati R. Cardanol-like co-surfactants solubilized in pegylated micelles keep their antioxidant activity and preserve polyethylene glycol chains from oxidation. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111465] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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24
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Viglianisi C, Pietro LD, Meoni V, Amorati R, Menichetti S. From simple phenols to potent chain-breaking antioxidants by transposition of benzo[1,4]oxathiines to benzo[b]thiophenes. ARKIVOC 2019. [DOI: 10.24820/ark.5550190.p011.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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25
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Baschieri A, Amorati R, Valgimigli L, Sambri L. 1-Methyl-1,4-cyclohexadiene as a Traceless Reducing Agent for the Synthesis of Catechols and Hydroquinones. J Org Chem 2019; 84:13655-13664. [DOI: 10.1021/acs.joc.9b01898] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Andrea Baschieri
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
| | - Riccardo Amorati
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
| | - Luca Valgimigli
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
| | - Letizia Sambri
- Dipartimento di Chimica Industriale “T. Montanari”Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
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26
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Viglianisi C, Vasa K, Tanini D, Capperucci A, Amorati R, Valgimigli L, Baschieri A, Menichetti S. Ditocopheryl Sulfides and Disulfides: Synthesis and Antioxidant Profile. Chemistry 2019; 25:9108-9116. [PMID: 31017702 DOI: 10.1002/chem.201901537] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Indexed: 12/14/2022]
Abstract
Symmetrical ditocopheryl disulfides (Toc)2 S2 and symmetrical and unsymmetrical ditocopheryl sulfides (Toc)2 S were simply prepared under remarkably mild conditions with complete control of the regiochemistry by using δ-, γ-, and β-tocopheryl-N-thiophthalimides (Toc-NSPht) as common starting materials. The roles of sulfur atom(s), H-bond and aryl ring substitution pattern on the antioxidant profile of these new compounds, which were assembled by linking together two tocopheryl units, are also discussed.
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Affiliation(s)
- Caterina Viglianisi
- Department of Chemistry "Ugo Schiff", University of Florence, Via Della Lastruccia 3-13, Sesto Fiorentino, Firenze, Italy
| | - Kristian Vasa
- Department of Chemistry "Ugo Schiff", University of Florence, Via Della Lastruccia 3-13, Sesto Fiorentino, Firenze, Italy
| | - Damiano Tanini
- Department of Chemistry "Ugo Schiff", University of Florence, Via Della Lastruccia 3-13, Sesto Fiorentino, Firenze, Italy
| | - Antonella Capperucci
- Department of Chemistry "Ugo Schiff", University of Florence, Via Della Lastruccia 3-13, Sesto Fiorentino, Firenze, Italy
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy
| | - Luca Valgimigli
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy
| | - Andrea Baschieri
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy
| | - Stefano Menichetti
- Department of Chemistry "Ugo Schiff", University of Florence, Via Della Lastruccia 3-13, Sesto Fiorentino, Firenze, Italy
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27
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Baschieri A, Pizzol R, Guo Y, Amorati R, Valgimigli L. Calibration of Squalene, p-Cymene, and Sunflower Oil as Standard Oxidizable Substrates for Quantitative Antioxidant Testing. J Agric Food Chem 2019; 67:6902-6910. [PMID: 31132263 DOI: 10.1021/acs.jafc.9b01400] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The autoxidation kinetics of stripped sunflower oil (SSO), squalene (SQ), and p-cymene ( p-C) initiated by 2,2'-azobis(isobutyronitrile) at 303 K were investigated under controlled conditions by differential oximetry in order to build reference model systems that are representative of the natural variability of oxidizable materials, for quantitative antioxidant testing. Rate constants for oxidative chain propagation ( kp) and chain termination (2 kt) and the oxidizability ( kp/√2 kt) were measured using 2,6-di- tert-butyl-4-methoxyphenol, 2,2,5,7,8-pentamethyl-6-chromanol, BHT, and 4-methoxyphenol as reference antioxidants. Measured values of kp (M-1 s-1)/2 kt (M-1 s-1)/oxidizability (M-1/2 s-1/2) at 303 K in chlorobenzene were 66.9/3.45 × 106/3.6 × 10-2, 68.0/7.40 × 106/2.5 × 10-2, and 0.83/2.87 × 106/4.9 × 10-4, respectively, for SSO, SQ, and p-C. Quercetin, magnolol, caffeic acid phenethyl ester, and 2,4,6-trimethylphenol were investigated to validate calibrations. The distinctive usefulness of the three substrates in testing antioxidants is discussed.
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Affiliation(s)
- Andrea Baschieri
- Department of Chemistry "G. Ciamician" , University of Bologna , Via S. Giacomo 11 , 40126 Bologna , Italy
| | - Romeo Pizzol
- Department of Chemistry "G. Ciamician" , University of Bologna , Via S. Giacomo 11 , 40126 Bologna , Italy
| | - Yafang Guo
- Department of Chemistry "G. Ciamician" , University of Bologna , Via S. Giacomo 11 , 40126 Bologna , Italy
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician" , University of Bologna , Via S. Giacomo 11 , 40126 Bologna , Italy
| | - Luca Valgimigli
- Department of Chemistry "G. Ciamician" , University of Bologna , Via S. Giacomo 11 , 40126 Bologna , Italy
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28
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Affiliation(s)
- Riccardo Amorati
- Department of Chemistry “G. Ciamician”, University of Bologna, Bologna, Italy
| | - Andrea Baschieri
- Department of Chemistry “G. Ciamician”, University of Bologna, Bologna, Italy
| | - Luca Valgimigli
- Department of Chemistry “G. Ciamician”, University of Bologna, Bologna, Italy
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29
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Baschieri A, Amorati R, Benelli T, Mazzocchetti L, D'Angelo E, Valgimigli L. Enhanced Antioxidant Activity under Biomimetic Settings of Ascorbic Acid Included in Halloysite Nanotubes. Antioxidants (Basel) 2019; 8:E30. [PMID: 30691231 PMCID: PMC6406349 DOI: 10.3390/antiox8020030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/21/2019] [Accepted: 01/24/2019] [Indexed: 12/31/2022] Open
Abstract
Antioxidant activity of native vitamin C (ascorbic acid, AH₂) is hampered by instability in solution. Selective loading of AH₂ into the inner lumen of natural halloysite nanotubes (HNT) yields a composite nanoantioxidant (HNT/AH₂), which was characterized and investigated for its reactivity with the persistent 1,1-diphenyl-2-picrylhydrazyl (DPPH•) radical and with transient peroxyl radicals in the inhibited autoxidation of organic substrates, both in organic solution (acetonitrile) and in buffered (pH 7.4) water in comparison with native AH₂. HNT/AH₂ showed excellent antioxidant performance being more effective than native ascorbic acid by 131% in acetonitrile and 290% (three-fold) in aqueous solution, under identical settings. Reaction with peroxyl radicals has a rate constant of 1.4 × 10⁶ M-1 s-1 and 5.1 × 10⁴ M-1 s-1, respectively, in buffered water (pH 7.4) and acetonitrile, at 30 °C. Results offer physical understanding of the factors governing HNT/AH₂ reactivity. Improved performance of HNT/AH₂ is unprecedented among forms of stabilized ascorbic acid and its relevance is discussed on kinetic grounds.
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Affiliation(s)
- Andrea Baschieri
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, I-40126 Bologna, Italy.
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, I-40126 Bologna, Italy.
| | - Tiziana Benelli
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy.
| | - Laura Mazzocchetti
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy.
| | - Emanuele D'Angelo
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy.
| | - Luca Valgimigli
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, I-40126 Bologna, Italy.
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30
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Viglianisi C, Menichetti S, Morelli P, Baschieri A, Amorati R. From catechol‐tocopherol to catechol‐hydroquinone polyphenolic antioxidant hybrids. Heteroatom Chem 2018. [DOI: 10.1002/hc.21466] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Caterina Viglianisi
- Department of Chemistry “Ugo Schiff”University of Florence Sesto Fiorentino Italy
| | - Stefano Menichetti
- Department of Chemistry “Ugo Schiff”University of Florence Sesto Fiorentino Italy
| | - Paola Morelli
- Department of Chemistry “Ugo Schiff”University of Florence Sesto Fiorentino Italy
| | - Andrea Baschieri
- Department of Chemistry “G. Ciamician”University of Bologna Bologna Italy
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”University of Bologna Bologna Italy
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31
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Foti MC, Amorati R, Baschieri A, Rocco C. Singlet oxygen quenching- and chain-breaking antioxidant-properties of a quercetin dimer able to prevent age-related macular degeneration. Biophys Chem 2018; 243:17-23. [PMID: 30352336 DOI: 10.1016/j.bpc.2018.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/18/2018] [Accepted: 10/03/2018] [Indexed: 01/07/2023]
Abstract
A dimer of quercetin prepared through a Mannich reaction protects pyridinium bisretinoid A2E from photooxidation at 430 nm in aqueous medium at pH 7.4. In the presence of light and O2, A2E is quickly attacked by 1O2 produced in situ (by excited A2E) to give nonaoxirane and other oxygenated compounds which can be involved in diseases of the macula. Peroxyl radicals might have only a marginal role on the photooxidation of A2E. The dimer is actually a potent quencher of 1O2 with a rate constant kQ of 8.5 × 108 M-1 s-1 in methanol at room temperature. On the other hand, its antioxidant abilities against ROO· radicals are quite limited since kROO· = 7.3 × 105 M-1 s-1 (in buffer solution at pH 7.4), the value being essentially identical to that of quercetin. The quenching of 1O2 by the dimer is therefore the main reason for the A2E protection and prevention of age-related macular degeneration.
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Affiliation(s)
- Mario C Foti
- Istituto di Chimica Biomolecolare del CNR, via P. Gaifami 18, I-95126 Catania, Italy.
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
| | - Andrea Baschieri
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
| | - Concetta Rocco
- Istituto di Chimica Biomolecolare del CNR, via P. Gaifami 18, I-95126 Catania, Italy
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32
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Baschieri A, Valgimigli L, Gabbanini S, DiLabio GA, Romero-Montalvo E, Amorati R. Extremely Fast Hydrogen Atom Transfer between Nitroxides and HOO· Radicals and Implication for Catalytic Coantioxidant Systems. J Am Chem Soc 2018; 140:10354-10362. [DOI: 10.1021/jacs.8b06336] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Andrea Baschieri
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
| | - Luca Valgimigli
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
| | - Simone Gabbanini
- R&D division, BeC s.r.l. Via C. Monteverdi 49, 47122 Forlì, Italy
| | - Gino A. DiLabio
- Department of Chemistry, University of British Columbia, 3247 University Way, Kelowna, British Columbia V1V 1V7, Canada
- Faculty of Management, University of British Columbia, 1137 Alumni Avenue, Kelowna, British Columbia V1V 1V7, Canada
| | - Eduardo Romero-Montalvo
- Department of Chemistry, University of British Columbia, 3247 University Way, Kelowna, British Columbia V1V 1V7, Canada
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
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Baschieri A, Del Secco B, Zaccheroni N, Valgimigli L, Amorati R. The Role of Onium Salts in the Pro-Oxidant Effect of Gold Nanoparticles in Lipophilic Environments. Chemistry 2018; 24:9113-9119. [PMID: 29689123 DOI: 10.1002/chem.201801110] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 04/06/2018] [Indexed: 01/11/2023]
Abstract
Metal nanoparticles are reported to be toxic due to the generation of free radicals at their surface. Relatively inert thiol-capped gold nanoparticles (AuNPs) have been reported to induce radical formation in the presence of hydroperoxides, which would conflict with their potential use as inert scaffolds for the design of novel nano-antioxidants. With the aim of clarifying this aspect, we investigated the pro-oxidant activity of dodecanethiol-capped AuNPs (∼5 nm diameter), prepared through the Brust-Schiffrin synthesis, by oxygen-uptake kinetic studies. The pro-oxidant activity was found to be proportional to the impurities of the transfer agent tetraoctylammonium bromide (TOAB) left from the synthesis and decreased on repeated washing of the nanoparticles. Under identical settings similar batches of AuNP (∼9 nm diameter) prepared through the Ulman method without onium salts showed no pro-oxidant behavior. The alternative onium phase-transfer agents Oct4 NBF4 (Oct=octyl), Hex4 NBF4 (Hex=hexyl), and Hex4 NPF6 were comparatively investigated and showed lower pro-oxidant activity depending on the counterion (Br- >PF6- >BF4- ).
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Affiliation(s)
- Andrea Baschieri
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy
| | - Benedetta Del Secco
- Department of Chemistry "G. Ciamician", University of Bologna, Via F. Selmi 2, 40126, Bologna, Italy
| | - Nelsi Zaccheroni
- Department of Chemistry "G. Ciamician", University of Bologna, Via F. Selmi 2, 40126, Bologna, Italy
| | - Luca Valgimigli
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy
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Tavakoli J, Hashemi SMB, Mousavi Khaneghah A, Barba FJ, Amorati R, Esmaeilzadeh Kenari R, Amarowicz R. Improving the Frying Performance and Oxidative Stability of Refined Soybean Oil by Tocotrienol-Rich Unsaponifiable Matters of Kolkhoung (Pistacia khinjuk) Hull Oil. J AM OIL CHEM SOC 2018. [DOI: 10.1002/aocs.12065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Javad Tavakoli
- Department of Food Science and Technology, Faculty of Agriculture; Jahrom University, Khalij Fars Street, P.O. Box 74131-88941; Jahrom Fars Iran
| | | | - Amin Mousavi Khaneghah
- Department of Food Science, Faculty of Food Engineering; State University of Campinas (UNICAMP), Monteiro Lobato, 80. Caixa Postal 6121, CEP 13083-862; Campinas São Paulo Brazil
| | - Francisco J. Barba
- Nutrition and Food Science Area, Preventive Medicine and Public Health, Food Science, Toxicology and Forensic Medicine Department, Faculty of Pharmacy; Universitat de València, Avda. Vicent Andrés Estellés, s/n, Burjassot; 46100 València Spain
| | - Riccardo Amorati
- Chemistry Department “G. Ciamician”; University of Bologna; Via S. Giacomo 11, 40126, Bologna Italy
| | - Reza Esmaeilzadeh Kenari
- Food Science and Technology Department, Faculty of Agricultural Engineering; Sari Agricultural Sciences and Natural Resources University; Km 9, Farah Abad Road, P.O. Box 48181-68984, Sari Mazandaran Iran
| | - Ryszard Amarowicz
- Institute of Animal Reproduction and Food Research; Polish Academy of Science, Tuwima 10; 10-748 Olsztyn Poland
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Abstract
Measurement of antioxidant properties in plant-derived compounds requires appropriate methods that address the mechanism of antioxidant activity and focus on the kinetics of the reactions involving the antioxidants. Methods based on inhibited autoxidations are the most suited for chain-breaking antioxidants and for termination-enhancing antioxidants, while different specific studies are needed for preventive antioxidants. A selection of chemical testing methods is critically reviewed, highlighting their advantages and limitations and discussing their usefulness to investigate both pure molecules and raw extracts. The influence of the reaction medium on antioxidants' performance is also addressed.
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Affiliation(s)
- Riccardo Amorati
- University of Bologna , Department of Chemistry "G. Ciamician" , Via S. Giacomo 11 , 40126 Bologna , Italy
| | - Luca Valgimigli
- University of Bologna , Department of Chemistry "G. Ciamician" , Via S. Giacomo 11 , 40126 Bologna , Italy
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Abstract
Nanomaterials represent one of the most promising frontiers in the research for improved antioxidants. Some nanomaterials, including organic (i.e. melanin, lignin) metal oxides (i.e. cerium oxide) or metal (i.e. gold, platinum) based nanoparticles, exhibit intrinsic redox activity that is often associated with radical trapping and/or with superoxide dismutase-like and catalase-like activities. Redox inactive nanomaterials can be transformed into antioxidants by grafting low molecular weight antioxidants on them. Herein, we propose a classification of nanoantioxidants based on their mechanism of action, and we review the chemical methods used to measure antioxidant activity by providing a rationale of the chemistry behind them.
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Affiliation(s)
- Luca Valgimigli
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, Bologna 40126, Italy.
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Baschieri A, Pulvirenti L, Muccilli V, Amorati R, Tringali C. Chain-breaking antioxidant activity of hydroxylated and methoxylated magnolol derivatives: the role of H-bonds. Org Biomol Chem 2018; 15:6177-6184. [PMID: 28695220 DOI: 10.1039/c7ob01195d] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chemical modification of magnolol, an uncommon dimeric neolignan contained in Magnolia genus trees, provides a unique array of polyphenols having interesting biological activity potentially related to radical scavenging. The chain-breaking antioxidant activity of four new hydroxylated and methoxylated magnolol derivatives was explored by experimental and computational methods. The measurement of the rate constant of the reaction with ROO˙ radicals (kinh) in an apolar solvent showed that the introduction of hydroxyl groups ortho to the phenolic OH in magnolol increased the kinh value, being 2.4 × 105 M-1 s-1 and 3.3 × 105 M-1 s-1 for the mono and the dihydroxy derivatives respectively (kinh of magnolol is 6.1 × 104 M-1 s-1). The di-methoxylated derivative is less reactive than magnolol (kinh = 1.1 × 104 M-1 s-1), while the insertion of both hydroxyl and methoxyl groups showed no effect (6.0 × 104 M-1 s-1). Infrared spectroscopy and theoretical calculations allowed a rationalization of these results and pointed out the crucial role of intramolecular H-bonds. We also show that a correct estimation of the rate constant of the reaction with ROO˙ radicals, by using BDE(OH) calculations, requires that the geometry of the radical is as close as possible to that of the parent phenol.
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Affiliation(s)
- Andrea Baschieri
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy.
| | - Luana Pulvirenti
- Department of Chemical Sciences, University of Catania, Viale A. Doria 6, I-95125 Catania, Italy
| | - Vera Muccilli
- Department of Chemical Sciences, University of Catania, Viale A. Doria 6, I-95125 Catania, Italy
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy.
| | - Corrado Tringali
- Department of Chemical Sciences, University of Catania, Viale A. Doria 6, I-95125 Catania, Italy
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Baschieri A, Ajvazi MD, Tonfack JLF, Valgimigli L, Amorati R. Explaining the antioxidant activity of some common non-phenolic components of essential oils. Food Chem 2017; 232:656-663. [DOI: 10.1016/j.foodchem.2017.04.036] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 02/06/2023]
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Amorati R, Baschieri A, Cowden A, Valgimigli L. The Antioxidant Activity of Quercetin in Water Solution. Biomimetics (Basel) 2017; 2:E9. [PMID: 31105172 PMCID: PMC6352608 DOI: 10.3390/biomimetics2030009] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 06/19/2017] [Accepted: 06/22/2017] [Indexed: 01/11/2023] Open
Abstract
Despite its importance, little is known about the absolute performance and the mechanism for quercetin's antioxidant activity in water solution. We have investigated this aspect by combining differential oxygen-uptake kinetic measurements and B3LYP/6311+g (d,p) calculations. At pH = 2.1 (30 °C), quercetin had modest activity (kinh = 4.0 × 103 M-1 s-1), superimposable to catechol. On raising the pH to 7.4, reactivity was boosted 40-fold, trapping two peroxyl radicals in the chromen-4-one core and two in the catechol with kinh of 1.6 × 105 and 7.0 × 104 M-1 s-1. Reaction occurs from the equilibrating mono-anions in positions 4' and 7 and involves firstly the OH in position 3, having bond dissociation enthalpies of 75.0 and 78.7 kcal/mol, respectively, for the two anions. Reaction proceeds by a combination of proton-coupled electron-transfer mechanisms: electron⁻proton transfer (EPT) and sequential proton loss electron transfer (SPLET). Our results help rationalize quercetin's reactivity with peroxyl radicals and its importance under biomimetic settings, to act as a nutritional antioxidant.
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Affiliation(s)
- Riccardo Amorati
- University of Bologna, Department of Chemistry "G. Ciamician", Via S. Giacomo 11, 40126 Bologna, Italy.
| | - Andrea Baschieri
- University of Bologna, Department of Chemistry "G. Ciamician", Via S. Giacomo 11, 40126 Bologna, Italy.
| | - Adam Cowden
- School of Chemistry (Rm 267), University of Edinburgh, West Mains Road, Edinburgh EH9 3FJ, UK.
| | - Luca Valgimigli
- University of Bologna, Department of Chemistry "G. Ciamician", Via S. Giacomo 11, 40126 Bologna, Italy.
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Amorati R, Valgimigli L, Viglianisi C, Schmallegger M, Neshchadin D, Gescheidt G. Proton-Coupled Electron Transfer from Hydrogen-Bonded Phenols to Benzophenone Triplets. Chemistry 2017; 23:5299-5306. [DOI: 10.1002/chem.201605931] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Indexed: 01/15/2023]
Affiliation(s)
- Riccardo Amorati
- University of Bologna; Department of Chemistry “G. Ciamician”; Via S. Giacomo 11 40126 Bologna Italy
| | - Luca Valgimigli
- University of Bologna; Department of Chemistry “G. Ciamician”; Via S. Giacomo 11 40126 Bologna Italy
| | - Caterina Viglianisi
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3-13 50019 Sesto Fiorentino Italy
| | - Max Schmallegger
- Institute of Physical and Theoretical Chemistry; Graz University of Technology, NAWI Graz; Stremayrgasse 9 8010 Graz Austria
| | - Dmytro Neshchadin
- Institute of Physical and Theoretical Chemistry; Graz University of Technology, NAWI Graz; Stremayrgasse 9 8010 Graz Austria
| | - Georg Gescheidt
- Institute of Physical and Theoretical Chemistry; Graz University of Technology, NAWI Graz; Stremayrgasse 9 8010 Graz Austria
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Bruno S, Uliassi E, Zaffagnini M, Prati F, Bergamini C, Amorati R, Paredi G, Margiotta M, Conti P, Costi MP, Kaiser M, Cavalli A, Fato R, Bolognesi ML. Molecular basis for covalent inhibition of glyceraldehyde-3-phosphate dehydrogenase by a 2-phenoxy-1,4-naphthoquinone small molecule. Chem Biol Drug Des 2017; 90:225-235. [DOI: 10.1111/cbdd.12941] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 12/16/2022]
Affiliation(s)
- Stefano Bruno
- Department of Pharmacy; University of Parma; Parma Italy
| | - Elisa Uliassi
- Department of Pharmacy and Biotechnology; Alma Mater Studiorum - University of Bologna; Bologna Italy
| | - Mirko Zaffagnini
- Department of Pharmacy and Biotechnology; Alma Mater Studiorum - University of Bologna; Bologna Italy
| | - Federica Prati
- Department of Pharmacy and Biotechnology; Alma Mater Studiorum - University of Bologna; Bologna Italy
| | - Christian Bergamini
- Department of Pharmacy and Biotechnology; Alma Mater Studiorum - University of Bologna; Bologna Italy
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”; Alma Mater Studiorum - University of Bologna; Bologna Italy
| | | | | | - Paola Conti
- Department of Pharmaceutical Sciences; University of Milan; Milan Italy
| | - Maria Paola Costi
- Department of Life Sciences; University of Modena and Reggio Emilia; Modena Italy
| | - Marcel Kaiser
- Swiss Tropical & Public Health Institute; Basel Switzerland
- University of Basel; Basel Switzerland
| | - Andrea Cavalli
- Department of Pharmacy and Biotechnology; Alma Mater Studiorum - University of Bologna; Bologna Italy
- CompuNet; Istituto Italiano di Tecnologia; Genova Italy
| | - Romana Fato
- Department of Pharmacy and Biotechnology; Alma Mater Studiorum - University of Bologna; Bologna Italy
| | - Maria Laura Bolognesi
- Department of Pharmacy and Biotechnology; Alma Mater Studiorum - University of Bologna; Bologna Italy
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Menichetti S, Amorati R, Meoni V, Tofani L, Caminati G, Viglianisi C. Role of Noncovalent Sulfur···Oxygen Interactions in Phenoxyl Radical Stabilization: Synthesis of Super Tocopherol-like Antioxidants. Org Lett 2016; 18:5464-5467. [DOI: 10.1021/acs.orglett.6b02557] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stefano Menichetti
- Department
of Chemistry “U. Schiff”, University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
| | - Riccardo Amorati
- Department
of Chemistry “Ciamician”, University of Bologna, Via San Giacomo 11, 40126 Bologna, Italy
| | - Valentina Meoni
- Department
of Chemistry “U. Schiff”, University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
| | - Lorenzo Tofani
- Department
of Chemistry “U. Schiff”, University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
| | - Gabriella Caminati
- Department
of Chemistry “U. Schiff”, University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
- CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Caterina Viglianisi
- Department
of Chemistry “U. Schiff”, University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
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43
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Cedrowski J, Litwinienko G, Baschieri A, Amorati R. Hydroperoxyl Radicals (HOO.
): Vitamin E Regeneration and H-Bond Effects on the Hydrogen Atom Transfer. Chemistry 2016; 22:16441-16445. [DOI: 10.1002/chem.201603722] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Indexed: 01/07/2023]
Affiliation(s)
- Jakub Cedrowski
- Faculty of Chemistry; University of Warsaw; Pasteura 1 02-093 Warsaw Poland
| | | | - Andrea Baschieri
- Department of Chemistry “G. Ciamician”; University of Bologna; Via S. Giacomo 11 40126 Bologna Italy
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”; University of Bologna; Via S. Giacomo 11 40126 Bologna Italy
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Amorati R, Baschieri A, Morroni G, Gambino R, Valgimigli L. Peroxyl Radical Reactions in Water Solution: A Gym for Proton-Coupled Electron-Transfer Theories. Chemistry 2016; 22:7924-34. [DOI: 10.1002/chem.201504492] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Indexed: 12/14/2022]
Affiliation(s)
- Riccardo Amorati
- Department of Chemistry “G. Ciamician”; University of Bologna; Via S. Giacomo 11 40126 Bologna Italy
| | - Andrea Baschieri
- Department of Chemistry “G. Ciamician”; University of Bologna; Via S. Giacomo 11 40126 Bologna Italy
| | - Gloria Morroni
- Department of Chemistry “G. Ciamician”; University of Bologna; Via S. Giacomo 11 40126 Bologna Italy
| | - Rossana Gambino
- Department of Chemistry “G. Ciamician”; University of Bologna; Via S. Giacomo 11 40126 Bologna Italy
| | - Luca Valgimigli
- Department of Chemistry “G. Ciamician”; University of Bologna; Via S. Giacomo 11 40126 Bologna Italy
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Haidasz EA, Meng D, Amorati R, Baschieri A, Ingold KU, Valgimigli L, Pratt DA. Acid Is Key to the Radical-Trapping Antioxidant Activity of Nitroxides. J Am Chem Soc 2016; 138:5290-8. [DOI: 10.1021/jacs.6b00677] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Evan A. Haidasz
- Department
of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Derek Meng
- Department
of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Riccardo Amorati
- Department
of Chemistry “G. Ciamician”, University of Bologna, Bologna I-40126, Italy
| | - Andrea Baschieri
- Department
of Chemistry “G. Ciamician”, University of Bologna, Bologna I-40126, Italy
| | - Keith U. Ingold
- National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Luca Valgimigli
- Department
of Chemistry “G. Ciamician”, University of Bologna, Bologna I-40126, Italy
| | - Derek A. Pratt
- Department
of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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Massaro M, Riela S, Guernelli S, Parisi F, Lazzara G, Baschieri A, Valgimigli L, Amorati R. A synergic nanoantioxidant based on covalently modified halloysite–trolox nanotubes with intra-lumen loaded quercetin. J Mater Chem B 2016; 4:2229-2241. [DOI: 10.1039/c6tb00126b] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Synergic antioxidant activity was achieved by grafting α-tocopherol derivatives on halloysite nanotubes, and by loading quercetin in the inner lumen.
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Affiliation(s)
- Marina Massaro
- University of Palermo
- Department STEBICEF
- section Chemistry
- I-90128 Palermo
- Italy
| | - Serena Riela
- University of Palermo
- Department STEBICEF
- section Chemistry
- I-90128 Palermo
- Italy
| | - Susanna Guernelli
- University of Bologna
- Department of Chemistry “G. Ciamician”
- I-40126 Bologna
- Italy
| | - Filippo Parisi
- University of Palermo
- Department of Physic and Chemistry
- 90128 Palermo
- Italy
| | - Giuseppe Lazzara
- University of Palermo
- Department of Physic and Chemistry
- 90128 Palermo
- Italy
| | - Andrea Baschieri
- University of Bologna
- Department of Chemistry “G. Ciamician”
- I-40126 Bologna
- Italy
| | - Luca Valgimigli
- University of Bologna
- Department of Chemistry “G. Ciamician”
- I-40126 Bologna
- Italy
| | - Riccardo Amorati
- University of Bologna
- Department of Chemistry “G. Ciamician”
- I-40126 Bologna
- Italy
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Viglianisi C, Amorati R, Di Pietro L, Menichetti S. A Straightforward Route to Potent Phenolic Chain-Breaking Antioxidants by Acid-Promoted Transposition of 1,4-Benzo[b]oxathiines to Dihydrobenzo[b]thiophenes. Chemistry 2015; 21:16639-45. [PMID: 26440303 DOI: 10.1002/chem.201502650] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Indexed: 12/25/2022]
Abstract
The transformation of simple phenols with limited antioxidant activity into potent chain-breaking antioxidants was achieved by a three-step protocol, consisting of the conversion of phenols into 1,4-benzo[b]oxathiines followed by an unprecedented acid-promoted transposition to o-hydroxydihydrobenzo[b]thiophenes, or dihydrobenzo[de]thiochromenes, starting from phenols or naphthols, respectively. These derivatives, bearing a benzo-fused heterocycle with a sulfide sulfur ortho to the phenolic OH, have a rate constant of reaction with alkylperoxyl radicals (kinh ) comparable to that of α-tocopherol. A solid rationale for the transposition mechanism as well as for the structure-antioxidant activity relationship is presented.
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Affiliation(s)
- Caterina Viglianisi
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3-13, 50019, Sesto Fiorentino, Firenze (Italy).
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126 Bologna (Italy)
| | - Leonardo Di Pietro
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3-13, 50019, Sesto Fiorentino, Firenze (Italy)
| | - Stefano Menichetti
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3-13, 50019, Sesto Fiorentino, Firenze (Italy).
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Amorati R, Zotova J, Baschieri A, Valgimigli L. Antioxidant Activity of Magnolol and Honokiol: Kinetic and Mechanistic Investigations of Their Reaction with Peroxyl Radicals. J Org Chem 2015; 80:10651-9. [PMID: 26447942 DOI: 10.1021/acs.joc.5b01772] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Magnolol and honokiol, the bioactive phytochemicals contained in Magnolia officinalis, are uncommon antioxidants bearing isomeric bisphenol cores substituted with allyl functions. We have elucidated the chemistry behind their antioxidant activity by experimental and computational methods. In the inhibited autoxidation of cumene and styrene at 303 K, magnolol trapped four peroxyl radicals, with a kinh of 6.1 × 10(4) M(-1) s(-1) in chlorobenzene and 6.0 × 10(3) M(-1) s(-1) in acetonitrile, and honokiol trapped two peroxyl radicals in chlorobenzene (kinh = 3.8 × 10(4) M(-1) s(-1)) and four peroxyl radicals in acetonitrile (kinh = 9.5 × 10(3) M(-1) s(-1)). Their different behavior arises from a combination of intramolecular hydrogen bonding among the reactive OH groups (in magnolol) and of the OH groups with the aromatic and allyl π-systems, as confirmed by FT-IR spectroscopy and DFT calculations. Comparison with structurally related 3,3',5,5'-tetramethylbiphenyl-4,4'-diol, 2-allylphenol, and 2-allylanisole allowed us to exclude that the antioxidant behavior of magnolol and honokiol is due to the allyl groups. The reaction of the allyl group with a peroxyl radical (C-H hydrogen abstraction) proceeds with rate constant of 1.1 M(-1) s(-1) at 303 K. Magnolol and honokiol radicals do not react with molecular oxygen and produce no superoxide radical under the typical settings of inhibited autoxidations.
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Affiliation(s)
- Riccardo Amorati
- Department of Chemistry "G. Ciamician", University of Bologna , Via S. Giacomo 11, 40126 Bologna, Italy
| | - Julija Zotova
- Department of Chemistry "G. Ciamician", University of Bologna , Via S. Giacomo 11, 40126 Bologna, Italy
| | - Andrea Baschieri
- Department of Chemistry "G. Ciamician", University of Bologna , Via S. Giacomo 11, 40126 Bologna, Italy
| | - Luca Valgimigli
- Department of Chemistry "G. Ciamician", University of Bologna , Via S. Giacomo 11, 40126 Bologna, Italy
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Benazza M, Danquigny A, Novogrocki G, Valgimigli L, Amorati R, Ferroni F, Demailly-Mullie C, Siriwardena A, Lesur D, Aubry F, Demailly G. Alditol thiacrowns via a ring-closing metathesis of carbohydrate-derived α,ω-dithioallylethers. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.06.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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