Modulation of arachidonic acid metabolism by phenols: relation to their structure and antioxidant/prooxidant properties

Alanko, Juha; Riutta, Asko; Holm, Päivi; Muchá, I.; Vapaatalo, Heikki; Metsä‐Ketelä, T.

doi:10.1016/s0891-5849(98)00179-8

Cited by 109 publications

(81 citation statements)

References 30 publications

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“…The immediate family members of flavonoids include flavones, isoflavones and 2,3-dihydroderivatives of flavone, namely flavanones, which are interconvertible with the isomeric chalcones. The flavonoids that contain multiple OH substitution have very strong antioxidant activities against peroxyl radicals (32).…”

Section: Herbal Medicines and Natural Compoundsmentioning

confidence: 99%

“…Several in vitro studies have demonstrated that flavonoids can scavenge superoxide, hydroxyl and peroxyl radicals, affecting various steps in the arachidonate cascade via cyclooxygenase-2 or lipoxygenase (32). In addition to these important effects, they have membrane-stabilizing properties and also affect some processes of intermediary metabolism and inhibit lipid peroxidation in different systems.…”

Section: Herbal Medicines and Natural Compoundsmentioning

confidence: 99%

“…Some of them have been shown to increase the mucosal content of prostaglandins and mucus in gastric mucosa, showing cytoprotective effects. Several of them prevent gastric mucosal lesions produced by various experimental ulcer models and protect the gastric mucosa against different necrotic agent (32).…”

Section: Herbal Medicines and Natural Compoundsmentioning

confidence: 99%

“…Many phenolic compounds, including catecholamines, have been shown to modulate the PGHS and 5-lipoxygenase pathways of arachidonic acid (32).…”

Section: Antioxidant Properties Of Artemisia Douglasiana Besser and Dmentioning

confidence: 99%

“…The modulation of hydroperoxide tone by phenols is probably the key element explaining the suppression of arachidonic acid metabolism by PGHS. The stimulatory effect of phenols on PGE 2 formation may be based on their ac-tion as co-substrates for the peroxidase reaction (32).…”

Section: Antioxidant Properties Of Artemisia Douglasiana Besser and Dmentioning

confidence: 99%

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Antioxidant properties of natural compounds used in popular medicine for gastric ulcers

Repetto

Llesuy

2002

Braz J Med Biol Res

426

277

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There is evidence concerning the participation of reactive oxygen species in the etiology and physiopathology of human diseases, such as neurodegenerative disorders, inflammation, viral infections, autoimmune pathologies, and digestive system disorders such as gastrointestinal inflammation and gastric ulcer. The role of these reactive oxygen species in several diseases and the potential antioxidant protective effect of natural compounds on affected tissues are topics of high current interest. To consider a natural compound or a drug as an antioxidant substance it is necessary to investigate its antioxidant properties in vitro and then to evaluate its antioxidant functions in biological systems. In this review article, we shall consider the role of natural antioxidants derived from popular plants to reduce or prevent the oxidative stress in gastric ulcer induced by ethanol.

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Section: Herbal Medicines and Natural Compoundsmentioning

confidence: 99%

Section: Herbal Medicines and Natural Compoundsmentioning

confidence: 99%

Section: Herbal Medicines and Natural Compoundsmentioning

confidence: 99%

“…Many phenolic compounds, including catecholamines, have been shown to modulate the PGHS and 5-lipoxygenase pathways of arachidonic acid (32).…”

Section: Antioxidant Properties Of Artemisia Douglasiana Besser and Dmentioning

confidence: 99%

Section: Antioxidant Properties Of Artemisia Douglasiana Besser and Dmentioning

confidence: 99%

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Antioxidant properties of natural compounds used in popular medicine for gastric ulcers

Repetto

Llesuy

2002

Braz J Med Biol Res

426

277

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The Effect of Ring Nitrogen Atoms on the Homolytic Reactivity of Phenolic Compounds: Understanding the Radical‐Scavenging Ability of 5‐Pyrimidinols

Valgimigli

Brigati

Pedulli

et al. 2003

Chemistry A European J

107

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Six substituted 5-pyrimidinols were synthesized, and the thermochemistry and kinetics of their reactions with free radicals were studied and compared to those of equivalently substituted phenols. To assess their potential as hydrogen-atom donors to free radicals, we measured their O-H bond dissociation enthalpies (BDEs) using the radical equilibration electron paramagnetic resonance technique. This revealed that the O-H BDEs in 5-pyrimidinols are, on average, about 2.5 kcal mol(-1) higher than those in equivalently substituted phenols. The results are in good agreement with theoretical predictions, and confirm that substituent effects on the O-H BDE of 5-pyrimidinol are essentially the same as those on the Obond;H BDE in phenol. The kinetics of the reactions of these compounds with peroxyl radicals has been studied by their inhibition of the AIBN-initiated autoxidation of styrene, and with alkyl and alkoxyl radicals by competition kinetics. Despite their larger O-H BDEs, 5-pyrimidinols appear to transfer their phenolic hydrogen-atom to peroxyl radicals as quickly as equivalently substituted phenols, while their reactivity toward alkyl radicals far exceeds that of the corresponding phenols. We suggest that this rate enhancement, which is large in the case of alkyl radical reactions, small in the case of peroxyl radical reactions, and nonexistent in the case of alkoxyl radical reactions, is due to polar effects in the transition states of these atom-transfer reactions. This hypothesis is supported by additional experimental and theoretical results. Despite this higher reactivity of 5-pyrimidinols towards radicals compared to phenols, electrochemical measurements indicate that they are more stable to one-electron oxidation than equivalently substituted phenols. For example, the 5-pyrimidinol analogues of 2,4,6-trimethylphenol and butylated hydroxytoluene (BHT) were found to have oxidation potentials approximately 400 mV higher than their phenolic counterparts, but reacted roughly one order of magnitude faster with alkyl radicals and at about the same rate with peroxyl radicals. The 5-pyrimidinol structure should, therefore, serve as a useful template for the rational design of novel air-stable radical scavengers and chain-breaking antioxidants that are more effective than phenols.

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Electrochemical determination of wine polyphenols using carbon electrodes: A review

Ndreka,

Isak,

Xhaxhiu

et al. 2024

Electroanalysis

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Modulation of arachidonic acid metabolism by phenols: relation to their structure and antioxidant/prooxidant properties

Cited by 109 publications

References 30 publications

Antioxidant properties of natural compounds used in popular medicine for gastric ulcers

Antioxidant properties of natural compounds used in popular medicine for gastric ulcers

The Effect of Ring Nitrogen Atoms on the Homolytic Reactivity of Phenolic Compounds: Understanding the Radical‐Scavenging Ability of 5‐Pyrimidinols

Electrochemical determination of wine polyphenols using carbon electrodes: A review

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