A comparative study of the inhibitory effects by caffeic acid, catechins and their related compounds on the generation of radicals in the reaction mixture of linoleic acid with iron ions

Abstract

Caffeic acid and (+)-catechin, which are abundantly contained in coffee and tea, are typical polyphenols. In order to know the relative magnitudes of antioxidant activity, effects by caffeic acid, (+)-catechin and their derivatives on the formation of 4-POBN/carbon-centered linoleic acid-derived radical adducts were examined in the control reaction mixture of linoleic acid with FeCl3 at 30°C for 168 h. In the presence of 1.0 mM of the polyphenols, peak to peak heights of the third ESR signal resulted in 7.7 ± 2.4% (n = 3) (caffeic acid), 145 ± 13% (n = 3) (quinic acid), 4.4 ± 0.0% (n = 3) (chlorogenic acid), 104 ± 4.4% (n = 3) (ferulic acid), 4.3 ± 0.0% (n = 3) (noradrenaline), 12.5 ± 10.9% (n = 3) (gallic acid), 38.1 ± 7.1% (n = 3) [(+)-catechin], 47.9 ± 11.7% (n = 3) [(–)-epicatechin], 56.5 ± 1.6% (n = 3) (epigallocatechin), 13.5 ± 1.7% (n = 3) (catechol) and 83.7 ± 7.8% (n = 3) (resorcinol) of the control reaction mixture. All the compounds with catechol moiety exerted potent inhibitory effects on the radical formation except for (+)-catechin, (–)-epicatechin and epigallocatechin. (+)-Catechin, (–)-epicatechin and epigallocatechin may not exert the inhibitory effect as much possibly because they are less stable compared with caffeic acid. The resorcinol moiety in these molecules may also weaken their antioxidant activity.

Hydrophilic Phytochelators in Iron Overload Condition

“…It inhibits free radical formation through both iron chelation and antioxidant activity (Ikeda et al, 2011). Nevertheless, investigations demonstrated that caffeic acid is less effective than catechin in inhibiting the reactive oxygen species formation (Matsui et al, 2017). It also did not cause much increase in iron incorporation in red blood cells in comparison to tropolone (Kontoghiorghes, 1988).…”

Modulation of redox-sensitive transcription factors with polyphenols as pathogenetically grounded approach in therapy of systemic inflammatory response

“…Only some of the phenolic acids (Protocatechuic acid, Gentisic acid, p -Coumaric acid) can lead to DNA fragmentation and impact on the redox metabolism of tumour cells [ [123] , [124] , [125] ]. Another mechanism underlying the cytotoxic activity of phenolic acids described on the example of Caffeic acid is the ability of this class of compounds to chelate iron ions [ 126 ]. Isoflavones genistein and daidzein show a minor cytotoxic effect against MCF-7 and HEK293 cancer cells [ 100 ].…”