scholarly journals The antioxidant activity of polysulfides: it's radical!

2019 ◽  
Vol 10 (19) ◽  
pp. 4999-5010 ◽  
Author(s):  
Jean-Philippe R. Chauvin ◽  
Markus Griesser ◽  
Derek A. Pratt
Keyword(s):  
Antioxidant Activity ◽  
Peroxyl Radicals ◽  
Primary Antioxidant ◽  
Homolytic Substitution

Sulfurized olefins (polysulfides) containing four (or more) sulfur atoms react efficiently with peroxyl radicals by homolytic substitution, accounting for their primary antioxidant activity.

Chalcogen effects on the primary antioxidant activity of chrysin and quercetin

2020 ◽  
Vol 44 (21) ◽  
pp. 9073-9082
Author(s):  
Romina Castañeda-Arriaga ◽  
Tiziana Marino ◽  
Nino Russo ◽  
J. Raúl Alvarez-Idaboy ◽  
Annia Galano
Keyword(s):  
Density Functional Theory ◽  
Antioxidant Activity ◽  
Aqueous Solutions ◽  
Density Functional ◽  
Peroxyl Radicals ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Primary Antioxidant

The effect of chalcogens on the scavenging power of chrysin and quercetin antioxidants against peroxyl radicals has been investigated in lipid and aqueous solutions, using the density functional theory.

Antioxidant activity of sugarcane molasses against 2,2′-azobis(2-amidinopropane) dihydrochloride-induced peroxyl radicals

2013 ◽  
Vol 141 (1) ◽  
pp. 466-472 ◽  
Author(s):  
Yonathan Asikin ◽  
Makoto Takahashi ◽  
Takashi Mishima ◽  
Masami Mizu ◽  
Kensaku Takara ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Peroxyl Radicals ◽  
Sugarcane Molasses

Evidence of Trolox and some gallates as synergistic protectors of erythrocytes against peroxyl radicals

1998 ◽  
Vol 76 (4) ◽  
pp. 661-664 ◽  
Author(s):  
J Wu ◽  
H Sugiyama ◽  
L -H Zeng ◽  
D Mickle ◽  
T -W Wu
Keyword(s):  
Antioxidant Activity ◽  
Vitamin E ◽  
Protective Effect ◽  
Propyl Gallate ◽  
Peroxyl Radical ◽  
Human Erythrocytes ◽  
Peroxyl Radicals ◽  
Methyl Ethyl ◽  
Radical Initiator ◽  
Individual Contributions

The peroxidation of human erythrocytes induced by peroxyl radical initiator and its inhibition by several gallate esters (e.g., propyl, methyl, ethyl) and Trolox (a more polar analogue of vitamin E) have been studied. The antioxidant activity was determined on erythrocytes against hemolysis generated by a thermal activator, 2,2prime-azobis-(2-amidinopropane)dihydrogenchloride. It was found that propyl gallate and its two analogues were more effective than Trolox in preventing cell lysis. However, the combination of gallate esters and Trolox produced a protective effect exceeding the arithmetic sum of their individual contributions. These perceived synergisms occur at more than one level of Trolox at a given level of a gallate ester.Key words: Trolox, gallates, synergism, peroxyl radicals.

scholarly journals Antioxidant Activity of Magnolol and Honokiol: Kinetic and Mechanistic Investigations of Their Reaction with Peroxyl Radicals

2015 ◽  
Vol 80 (21) ◽  
pp. 10651-10659 ◽  
Author(s):  
Riccardo Amorati ◽  
Julija Zotova ◽  
Andrea Baschieri ◽  
Luca Valgimigli
Keyword(s):  
Antioxidant Activity ◽  
Peroxyl Radicals ◽  
Mechanistic Investigations

scholarly journals Penetapan Total Flavonoid, Aktivitas Antioksidan dan Karakterisasi Nanopartikel Ekstrak Etanol Daun Kelor (Moringa pterygosperma Gaertn.)

2019 ◽  
Vol 11 (1) ◽  
pp. 49
Author(s):  
Tinta Julianawati ◽  
Hendy Hendarto ◽  
Widjiati Widjiati
Keyword(s):  
Antioxidant Activity ◽  
Particle Size ◽  
Herbal Medicine ◽  
Leaf Extract ◽  
Total Flavonoid ◽  
Peroxyl Radicals ◽  
Chemical Components ◽  
Dpph Method ◽  
Moringa Leaf Extract

Moringa pterygosperma is one of the plants in Indonesia that is often used in herbal medicine. Moringa leaves contain many phytochemical compounds, one of the compounds is flavonoids which function as antioxidants. Flavonoid compounds in vitro can inhibit lipid peroxidation by breaking the chain of peroxyl radicals. Moringa leaf benefits in the field of herbal medicine are formed with a variety of preparations. One of the preparations is in the form of extracts with the aim of attracting chemical components to natural materials The extraction process has a disadvantage because the level of solubility in water is still low. The nanoparticle technique is a strategy to increase the bioavalbicibility of herbal active compounds. This research was experimental in order to determine the total flavonoid levels contained in Moringa leaf extract. In addition, it was also to find out the antioxidant activity and particle size of the moringa leaf extract nanoparticles. Determination of flavonoid levels using spectrophotometric methods. The antioxidant activity of moringa leaf extract nanoparticles was tested using the DPPH method (2,2-diphenyl-picrylhdrazyl) and to determine the particle size used by using the Particle Size Analyzer (PSA). The results of the study showed total flavonoid levels in moringa leaf extract (1.97 ± 1.07)%. Antioxidant activity of 451.8 ppm with a reduction of 2.8% and particle size in the moringa leaf extract nanoparticles of ± 134.78 nm. Moringa leaf extract nanoparticles include low antioxidants. Keywords: moringa; nanoparticles; antioxidants

scholarly journals Penetapan Total Flavonoid, Aktivitas Antioksidan dan Karakterisasi Nanopartikel Ekstrak Etanol Daun Kelor (Moringa pterygosperma Gaertn.)

2019 ◽  
Vol 11 (1) ◽  
pp. 49
Author(s):  
Tinta Julianawati ◽  
Hendy Hendarto ◽  
Widjiati Widjiati
Keyword(s):  
Antioxidant Activity ◽  
Particle Size ◽  
Herbal Medicine ◽  
Leaf Extract ◽  
Total Flavonoid ◽  
Peroxyl Radicals ◽  
Chemical Components ◽  
Dpph Method ◽  
Moringa Leaf Extract

Moringa pterygosperma is one of the plants in Indonesia that is often used in herbal medicine. Moringa leaves contain many phytochemical compounds, one of the compounds is flavonoids which function as antioxidants. Flavonoid compounds in vitro can inhibit lipid peroxidation by breaking the chain of peroxyl radicals. Moringa leaf benefits in the field of herbal medicine are formed with a variety of preparations. One of the preparations is in the form of extracts with the aim of attracting chemical components to natural materials The extraction process has a disadvantage because the level of solubility in water is still low. The nanoparticle technique is a strategy to increase the bioavalbicibility of herbal active compounds. This research was experimental in order to determine the total flavonoid levels contained in Moringa leaf extract. In addition, it was also to find out the antioxidant activity and particle size of the moringa leaf extract nanoparticles. Determination of flavonoid levels using spectrophotometric methods. The antioxidant activity of moringa leaf extract nanoparticles was tested using the DPPH method (2,2-diphenyl-picrylhdrazyl) and to determine the particle size used by using the Particle Size Analyzer (PSA). The results of the study showed total flavonoid levels in moringa leaf extract (1.97 ± 1.07)%. Antioxidant activity of 451.8 ppm with a reduction of 2.8% and particle size in the moringa leaf extract nanoparticles of ± 134.78 nm. Moringa leaf extract nanoparticles include low antioxidants. Keywords: moringa; nanoparticles; antioxidants

scholarly journals How Does Pyridoxamine Inhibit the Formation of Advanced Glycation End Products? The Role of Its Primary Antioxidant Activity

Antioxidants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 344 ◽  
Author(s):  
Rafael Ramis ◽  
Joaquín Ortega-Castro ◽  
Carmen Caballero ◽  
Rodrigo Casasnovas ◽  
Antonia Cerrillo ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Advanced Glycation End Products ◽  
Rate Constants ◽  
Protein Glycation ◽  
Diffusion Limit ◽  
Advanced Glycation ◽  
Hydrogen Atoms ◽  
Glycation End Products ◽  
End Products ◽  
Primary Antioxidant

Pyridoxamine, one of the natural forms of vitamin B6, is known to be an effective inhibitor of the formation of advanced glycation end products (AGEs), which are closely related to various human diseases. Pyridoxamine forms stable complexes with metal ions that catalyze the oxidative reactions taking place in the advanced stages of the protein glycation cascade. It also reacts with reactive carbonyl compounds generated as byproducts of protein glycation, thereby preventing further protein damage. We applied Density Functional Theory to study the primary antioxidant activity of pyridoxamine towards three oxygen-centered radicals (•OOH, •OOCH3 and •OCH3) to find out whether this activity may also play a crucial role in the context of protein glycation inhibition. Our results show that, at physiological pH, pyridoxamine can trap the •OCH3 radical, in both aqueous and lipidic media, with rate constants in the diffusion limit (>1.0 × 108 M - 1 s - 1 ). The quickest pathways involve the transfer of the hydrogen atoms from the protonated pyridine nitrogen, the protonated amino group or the phenolic group. Its reactivity towards •OOH and •OOCH3 is smaller, but pyridoxamine can still scavenge them with moderate rate constants in aqueous media. Since reactive oxygen species are also involved in the formation of AGEs, these results highlight that the antioxidant capacity of pyridoxamine is also relevant to explain its inhibitory role on the glycation process.

scholarly journals Enhanced Antioxidant Activity under Biomimetic Settings of Ascorbic Acid Included in Halloysite Nanotubes

Antioxidants ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 30 ◽  
Author(s):  
Andrea Baschieri ◽  
Riccardo Amorati ◽  
Tiziana Benelli ◽  
Laura Mazzocchetti ◽  
Emanuele D’Angelo ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Halloysite Nanotubes ◽  
Peroxyl Radicals ◽  
Organic Substrates ◽  
Dpph Radical ◽  
Organic Solution ◽  
Water Ph ◽  
Improved Performance

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.

Introduction of primary antioxidant activity to chitosan for application as a multifunctional food packaging material

2013 ◽  
Vol 33 (2) ◽  
pp. 207-214 ◽  
Author(s):  
Stephanie B. Schreiber ◽  
Joseph J. Bozell ◽  
Douglas G. Hayes ◽  
Svetlana Zivanovic
Keyword(s):  
Antioxidant Activity ◽  
Food Packaging ◽  
Packaging Material ◽  
Primary Antioxidant
Sign in / Sign up

Export Citation Format

Share Document