In Vitro Evaluation of Pro- and Antioxidant Effects of Flavonoid Tricetin in Comparison to Myricetin

Abstract

Flavonoids are rather common plant phenolic constituents that are known for potent antioxidant effects and can be beneficial for human health. Flavonoids with a pyrogallol moiety are highly efficient reducing agents with possible pro- and antioxidant effects, depending on the reaction milieu. Therefore, the redox properties of myricetin and tricetin were investigated by differential pulse voltammetry and deoxyribose degradation assay. Tricetin proved to be a good antioxidant but only showed negligible pro-oxidant activity in one of the deoxyribose degradation assay variants. Compared to tricetin, myricetin showed pro- and antioxidant effects. The more efficient reducing properties of myricetin are probably caused by the positive mesomeric effect of the enolic 3-hydroxy group on ring C. It is evident that the antioxidant properties of structurally similar flavonoids can be converted to apparent pro-oxidant effects by relatively small structural changes, such as hydroxylation. Since reactive oxygen species (ROS) often serve as secondary messengers in pathological and physiological processes in animal and plant cells, the pro- and antioxidant properties of flavonoids are an important part of controlling mechanisms of tissue signal cascades.

(±)-Catechin—A Mass-Spectrometry-Based Exploration Coordination Complex Formation with FeII and FeIII

“…Electroanalytical methods are efficient tools for redox, antioxidant, and coordination complexes explorations [7,[65][66][67]. The DPV concurs with the results of nano-ESI-MS.…”

Hydroxylation decoration patterns of flavonoids in horticultural crops: chemistry, bioactivity, and biosynthesis

“…Apart from the hydroxylations on the B ring, hydroxyl substituents present on either the C or A ring may also affect the biological activity of flavonoids ( Table 2 ). For instance, myricetin shows enhanced pro- and antioxidant effects compared with tricetin, which may be due to the positive mesomeric effect of the enolic 3-hydroxy group on the C-ring [ 73 ]. Kaempferol has a stronger inhibitory effect on α-glucoside and α-amylase with the substitution of an additional hydroxyl group at the C3 position of apigenin [ 74 ].…”

Concentration Dependence of Anti- and Pro-Oxidant Activity of Polyphenols as Evaluated with a Light-Emitting Fe2+-Egta-H2O2 System

“…Plant polyphenols can act as antioxidants or pro-oxidants depending on the kind of studied compound and are used in Fenton systems in vitro [ 9 , 18 ]. For instance, myricetin inhibited deoxyribose degradation by the Fe 3+ -EDTA-H 2 O 2 -ascorbic acid system and enhanced this process by Fe 3+ -EDTA.…”

“…For instance, myricetin inhibited deoxyribose degradation by the Fe 3+ -EDTA-H 2 O 2 -ascorbic acid system and enhanced this process by Fe 3+ -EDTA. On the other hand, tricetin (which differs from myricetin in the lack of -OH group on ring C at C 3 ) also protected deoxyribose from oxidative damage induced by Fe 3+ -EDTA-H 2 O 2 -ascorbic acid, whereas it had a very weak pro-oxidant effect in the case of Fe 3+ -EDTA [ 18 ]. In another study, the effect of 13 phenolics on Fe 2+ -EDTA-H 2 O 2 -induced deoxyribose degradation was evaluated; 4 of them significantly protected deoxyribose (antioxidant effect), and 7 revealed significant pro-oxidant activity.…”