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Antioxidants
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Free Radicals
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Free Radicals

A special issue of Antioxidants (ISSN 2076-3921).

Deadline for manuscript submissions: closed (30 August 2013) | Viewed by 43926

Special Issue Editor

Prof. Dr. Isabel C.F.R. Ferreira

grade E-Mail Website
Guest Editor
Centro de Investigação de Montanha CIMO, Instituto Politécnico de Bragança, Campus de Santa Apolónia, P-5300253 Bragança, Portugal
Interests: food chemistry; natural products; functional foods
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Contributions for this issue, both in form of original research and review articles, may cover all aspects related to free radicals belonging to oxygen, nitrogen or sulfur reactive species including methodologies of analysis that elucidate their production, cellular targets and mechanisms of action. Contributions related to antioxidant defences (enzymatic and non enzymatic) that act against free radicals are well come, as also the role of natural products or synthetic products in the help of endogenous antioxidant defence system. In this perspective, the antioxidants present on the diet assume a major importance and contributions describing analysis or isolation of phytochemicals or other bioactive compounds with antioxidant activity are interesting. The synthesis or use of synthetic compounds with activity towards free radicals is also of interest. Contributions reporting prooxidant role of free radicals and their potential benefits or adverse effects are well come, and finally studies describing relations between free radicals and medicine, ageing or food conservation, for example.

Dr. Isabel C. F. R. Ferreira
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Antioxidants is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • free radicals
  • reactive species
  • mechanisms
  • enzymatic/non-enzymatic defences
  • natural/synthetic antioxidants
  • prooxidants
  • applications
  • medicine
  • ageing

Published Papers (4 papers)

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Research

590 KiB  
Article
Free Radical Scavenging and Antioxidant Activities of Silymarin Components
by Kevin P. Anthony and Mahmoud A. Saleh
Antioxidants 2013, 2(4), 398-407; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox2040398 - 10 Dec 2013
Cited by 73 | Viewed by 10706
Abstract
Silymarin is an over the counter food supplement that is sold as a liver enhancement and liver protection preparation. It is a major constituent of the seeds of Silybum marianum which is composed of a mixture of seven major components and several minor [...] Read more.
Silymarin is an over the counter food supplement that is sold as a liver enhancement and liver protection preparation. It is a major constituent of the seeds of Silybum marianum which is composed of a mixture of seven major components and several minor compounds. The seven major components: taxifolin, silychristin, silydianin, silybin A, silybin B, iso-silybin A and iso-silybin B were isolated and purified from the crude mixture of silymarin using preparative high performance liquid chromatography to determine which were the most effective for liver protection. Free radical scavenging, hydroxyl radical antioxidant capacity, oxygen radical antioxidant capacity, trolox-equivalent antioxidant capacity and total antioxidant capacity antioxidant activities were determined for each of the individual purified components as well as the crude silymarin mixture. Taxifolin was the most effective component for scavenging free radicals in the DPPH assay with an EC50 of 32 µM far more effective than all other components which showed EC50 ranging from 115 to 855 µM. Taxifolin was also found to be the most effective antioxidant in the oxygen radical antioxidant capacity (ORAC) assay with a trolox equivalent of 2.43 and the second most effective in the hydroxyl radical antioxidant capacity (HORAC) assay with a gallic acid equivalent of 0.57. Other antioxidants assays did not show significant differences between samples. Full article
(This article belongs to the Special Issue Free Radicals)
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823 KiB  
Article
Comparison of Antioxidant Properties of Refined and Whole Wheat Flour and Bread
by Lilei Yu, Anne-Laure Nanguet and Trust Beta
Antioxidants 2013, 2(4), 370-383; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox2040370 - 26 Nov 2013
Cited by 111 | Viewed by 16269
Abstract
Antioxidant properties of refined and whole wheat flour and their resultant bread were investigated to document the effects of baking. Total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) were employed to determine the content of ethanol [...] Read more.
Antioxidant properties of refined and whole wheat flour and their resultant bread were investigated to document the effects of baking. Total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) were employed to determine the content of ethanol extractable phenolic compounds. HPLC was used to detect the presence of phenolic acids prior to their confirmation using LC-MS/MS. Whole wheat flour showed significantly higher antioxidant activity than refined flour (p < 0.05). There was a significant effect of the bread-making process with the TPC of whole wheat bread (1.50–1.65 mg/g) and white bread (0.79–1.03 mg/g) showing a respective reduction of 28% and 33% of the levels found in whole wheat and refined flour. Similarly, baking decreased DPPH radical scavenging capacity by 32% and 30%. ORAC values, however, indicated that baking increased the antioxidant activities of whole wheat and refined flour by 1.8 and 2.9 times, respectively. HPLC analysis showed an increase of 18% to 35% in ferulic acid after baking to obtain whole and refined wheat bread containing 330.1 and 25.3 µg/g (average), respectively. Whole wheat flour and bread were superior to refined flour and bread in in vitro antioxidant properties. Full article
(This article belongs to the Special Issue Free Radicals)
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2013 KiB  
Article
Valuing the Endangered Species Antirrhinum lopesianum: Neuroprotective Activities and Strategies for in vitro Plant Propagation
by Andreia Gomes, Sofia Fortalezas, Rui Pimpão, Inês Figueira, João Maroco, Carlos Aguiar, Ricardo B. Ferreira, Célia Miguel and Cláudia N. Santos
Antioxidants 2013, 2(4), 273-292; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox2040273 - 28 Oct 2013
Cited by 7 | Viewed by 7991
Abstract
Plant phytochemicals are described as possessing considerable neuroprotective properties, due to radical scavenging capacity and acetylcholinesterase inhibitory activity, important bioactivities in neurodegeneration. Antirrhinum lopesianum is a rare endemism from the Iberian Peninsula, occurring at the northeastern border between Portugal and Spain. It is [...] Read more.
Plant phytochemicals are described as possessing considerable neuroprotective properties, due to radical scavenging capacity and acetylcholinesterase inhibitory activity, important bioactivities in neurodegeneration. Antirrhinum lopesianum is a rare endemism from the Iberian Peninsula, occurring at the northeastern border between Portugal and Spain. It is classified as Endangered, due to its highly fragmented geographical occupation, facing a high risk of extinction in the Portuguese territory, within 20 years. Here, we describe for the first time the chemical characterization of extracts of the species concerning total phenol content, flavonoid content and antioxidant properties. The profile of high performance liquid chromatography with diode array detector (HPLC-DAD) of the polyphenol-enriched fraction of plant extracts was also performed, showing the great potential of the species as a source of bioactive phytochemical compounds. A. lopesianum’s potential for neuroprotection was revealed by a significant acetylcholinesterase inhibitory activity and also by a neuroprotective effect on a human cell model of neurodegeneration. Moreover, this is the first report describing a successful procedure for the in vitro propagation of this endangered species. The comparison of phenolic content and the HPLC-DAD profile of wild and in vitro propagated plants revealed that in vitro plants maintain the ability to produce secondary metabolites, but the profiles are differentially affected by the growth regulators. The results presented here greatly contribute to the value for this species regarding its potential as a source of phytochemicals with prospective neuroprotective health benefits. Full article
(This article belongs to the Special Issue Free Radicals)
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596 KiB  
Article
Relevance of the Mention of Antioxidant Properties in Yogurt Labels: In Vitro Evaluation and Chromatographic Analysis
by Eliana Pereira, Lillian Barros and Isabel C. F. R. Ferreira
Antioxidants 2013, 2(2), 62-76; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox2020062 - 18 Jun 2013
Cited by 12 | Viewed by 7714
Abstract
The purpose of the inclusion of fruit (natural additives) in yogurt aims to increase its antioxidant activity and functionality. Herein, a comparative study of the antioxidant potential of yogurts with pieces of various fruits was performed, including yogurts with mention of antioxidant properties [...] Read more.
The purpose of the inclusion of fruit (natural additives) in yogurt aims to increase its antioxidant activity and functionality. Herein, a comparative study of the antioxidant potential of yogurts with pieces of various fruits was performed, including yogurts with mention of antioxidant properties in the label. Free radicals scavenging activity, reducing power and inhibition of lipid peroxidation were evaluated by in vitro assays, as were the contents in antioxidants such as phenolics, flavonoids, sugars and tocopherols. After analyzing thirteen yogurts containing fruit pieces and a natural one (control), the most interesting were yogurts with pieces of berries (for phenolics, flavonoids and 2,2-dipheny-1-picrylhydrazyl (DPPH) scavenging activity), pineapple (for reducing power), blackberry (for β-carotene bleaching inhibition), blackberry “antioxidant” (for tocopherols) and cherry (for sugars). The mention of “antioxidant” in the label was relevant for tocopherols, sugars, DPPH scavenging activity and reducing power. No synergisms were observed in yogurts prepared with pieces of different fruits. Nevertheless, the addition of fruit pieces to yogurt was favorable for antioxidant content, increasing the protection of the consumer against diseases related to oxidative stress. Full article
(This article belongs to the Special Issue Free Radicals)
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