Comparison of Antioxidant Properties of a Conjugate of Taxifolin with Glyoxylic Acid and Selected Flavonoids

Abstract

It is known that flavonoids can react with toxic carbonyl compounds in the process of the storage, aging, and digestion of flavonoid-rich foods and beverages. However, the effect of these reactions on the antioxidant properties of the polyphenolic fraction and the properties of the resulting products remain poorly studied. The aim of the present work was to study the antioxidant activity of quercetin, taxifolin, catechin, eriodictyol, hesperetin, naringenin and a product of the condensation of taxifolin with glyoxylic acid, as well as to reveal the structure–activity relationship of these polyphenols. It was found that flavonoids containing the catechol moiety exhibited higher antioxidant activity than hesperetin and naringenin. The product showed the highest hydrogen peroxide scavenging activity, a lower metal-reducing and a higher iron-binding ability than catechol-containing flavonoids, and a lipid peroxidation inhibitory activity comparable with that of taxifolin. Thus, the condensation of flavonoids with toxic carbonyl compounds might lead to the formation of products exhibiting high antioxidant activity. Meanwhile, the conditions under which parent flavonoids and their products exhibit the maximal antioxidant activity may differ. The data suggest that the antioxidant profile of the polyphenolic fraction and bioavailability of polyphenols, carbonyl compounds, and metal ions may change when these reactions occur.

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

“…Mass spectra proved that catechin forms coordination complexes with both Fe II and Fe III separately (Tables 1 and 2). The isotopic pattern of the detected complexes corresponded to the characteristic isotopic pattern of iron ( 54 Fe 5.8%, 56 Fe 91.7%, 57 Fe 2.2%, and 58 Fe 0.3%). The spectra recorded after addition of Fe II or Fe III to the catechin solution were similar (Figure 2a,b).…”

“…Catechin can stabilize the redox homeodynamic equilibrium by direct reduction of ROS to water or by the formation of Fe-catechin coordination complexes in which the iron is less catalytically active. However, many studies on the abilities of flavonoids to be ligands in iron coordination complexes and to reduce Fe III to Fe II are performed primarily with photometric methods that employ ferrozine or other competitive ligands [45,58,59]. The results of such methods can be affected by the preferred oxidation stage of the liganded metal (Guldberg and Waage's law) [60].…”

Development of Lepidium sativum Extracts/PVA Electrospun Nanofibers as Wound Healing Dressing

“…The antioxidant ability to reduce the ABTS generated in the aqueous phase resulting in decreasing the color was 758.92 and 57.14 μM Trolox equivalent/mg extract for the total ethanol extract (70%) and polysaccharide of L. sativum seeds, respectively. Major flavonoids (catechin and quercetin) showed excellent radical scavenging activity, 57 and the high radical scavenging activity of TEE compared to poly might be attributed to the presence of these compounds.…”

Plicosepalus acacia Extract and Its Major Constituents, Methyl Gallate and Quercetin, Potentiate Therapeutic Angiogenesis in Diabetic Hind Limb Ischemia: HPTLC Quantification and LC-MS/MS Metabolic Profiling

“…Polyphenols have free radical scavenging, antioxidant, anti-aging, hepatoprotective, and reno-protective activities [ 47 , 48 ]. The antioxidant activity of quercetin, taxifolin, catechin, hesperetin, and naringenin was previously assessed through their capability to perform hydrogen peroxide scavenging activity, their lower metal-reducing ability, and their lipid peroxidation inhibitory activity [ 49 ]. The hypolipidemic and hypoglycemic effects of quercetin were reported through its ability to ameliorate insulin resistance, lower plasma triglyceride levels, and reduce liver fat accumulation [ 50 ].…”