Fast Antioxidant Reaction of Polyphenols and Their Metabolites

Abstract

The negative correlation between diets rich in fruits and vegetables and the occurrence of cardiovascular disease, stroke, cancer, atherosclerosis, cognitive impairment and other deleterious conditions is well established, with flavonoids and other polyphenols held to be partly responsible for the beneficial effects. Initially, these effects were explained by their antioxidant ability, but the low concentrations of polyphenols in tissues and relatively slow reaction with free radicals suggested that, instead, they act by regulating cell signalling pathways. Here we summarise results demonstrating that the abandonment of an antioxidant role for food polyphenols is based on incomplete knowledge of the mechanism of the polyphenol-free radical reaction. New kinetic measurements show that the reaction is up to 1000 times faster than previously reported and lowers the damaging potential of the radicals. The results also show that the antioxidant action does not require phenolic groups, but only a carbon-centred free radical and an aromatic molecule. Thus, not only food polyphenols but also many of their metabolites are effective antioxidants, significantly increasing the antioxidant protection of cells and tissues. By restoring an important antioxidant role for food polyphenols, the new findings provide experimental support for the advocacy of diets rich in plant-derived food.

Optimized ultrasound-assisted extraction of phenolic compounds from Thymus comosus Heuff. ex Griseb. et Schenk (wild thyme) and their bioactive potential

“…One of the most-cited bioactivities of phenolic-rich extracts obtained from plant matrices is the antioxidant potential, the mechanisms of this action being extensively studied [42] , [49] . Hence, many in vitro methods were developed to evaluate antioxidant activity to achieve an in-depth approach regarding how different phenolic compounds or complexes can act as modulators of oxidative processes [50] .…”

The Biochemistry and Effectiveness of Antioxidants in Food, Fruits, and Marine Algae

“…They prevent skin aging and degenerative diseases, such as cardiovascular diseases, and osteoporosis [ 219 ] and have anticarcinogenic properties by suppressing tumor formation and progression [ 221 , 222 , 223 ]. Polyphenols, such as quercetin, resveratrol, and curcumin, are more potent antioxidants than vitamins C and E, having a faster antioxidant action [ 224 , 225 ], and enhancing the therapeutic profiles [ 226 ]. Polyphenols are represented by several thousand plant-based molecules with antioxidant properties [ 227 ], classified into flavonoids (i.e., anthocyanins, flavanols, flavanones, flavonols, flavonones, flavones, and isoflavones) and non-flavonoids (i.e., phenolic acids, xanthones, stilbens, lignans, and tannins), and known for their high potential application in food preservation and for therapeutic beneficial use [ 227 ].…”

“…Vitamin C or L-ascorbic acid is essential in maintaining health as it prevents and fights infections, promotes wound healing, and prevents stress and fatigue [ 224 , 225 ]. Vitamin C is also involved in skin health and protection, preventing the appearance of wrinkles as well [ 240 ].…”

“…Vitamin C is also involved in skin health and protection, preventing the appearance of wrinkles as well [ 240 ]. Vitamin C is a water-soluble vitamin and is also considered one of the most important antioxidants, acting at the level of extracellular fluids [ 224 , 225 ]. Due to its properties, its lack in the body leads to a drastic decrease in the immune system in the fight against infections [ 241 ].…”

Effects of polyphenol-rich interventions on sleep disorders: A systematic review and meta-analysis

“…Polyphenols are secondary plant metabolites that are discovered in plant-derived herbal medicine, as well as foods like fruits and vegetables and nuts ( Abdel-Moneim et al, 2020 ; Alara et al, 2021 ; Gebicki and Nauser, 2021 ), which are composed of a broad diversity of molecules sharing an analogous elementary polyphenolic structure (e.g. lots of hydroxyl groups of aromatic rings) as well as molecules with a single phenol ring, including phenolic alcohols and phenolic acids.…”