Antioxidant capacity of (+)-catechin visible-light photoirradiated in the presence of vitamin B₂

Abstract

pH-effect of the medium on radical-scavenging activity comes from the increased electron-donating ability of CTQ upon deprotonation. These results are very interesting due to the fact that the pH of the food products displays important variations. The [Formula: see text]-scavenging ability of CTQ, would be equal to the additive contribution of each reactive center, CTC, and RSC, present at the molecule of CTQ. However, CTQ would have a moderate ability to removal of [Formula: see text]-species at pH 7.

Antioxidant ability of tyrosol and derivative-compounds in the presence of O2(1Δg)-species. Studies of synergistic antioxidant effect with commercial antioxidants

“…Criado, Gutierrez, Avila, Bertolotti, and Garcia (1996b) demonstrated that the ionization of the -OH groups in hydroxyflavones has a great influence on their reaction kinetics. Similar results have been reported for (+)-catechin and derivatives (Barua, Escalada, Bregliani, Pajares, & Criado, 2016).…”

“…As can be seen from both Tables, the ionization of the phenolic group produces a significant increase of k r values. This dependence of k r values on the degree of ionization of -OH group has been reported (Barua, Escalada, Bregliani, Pajares, & Criado, 2016;Bertolotti, Arguello, & García, 1991;García, 1994;). As mentioned above, taking into account the pKa values for Phd, at pH 11-12 a significant percentage of molecules would have their phenolic group ionized.…”

The Influence of the Degradation of Tetracycline by Free Radicals from Riboflavin-5′-Phosphate Photolysis on Microbial Viability

“…flavins + normalhsans-serifν → 1flavins→ 3flavins* where 1 flavins * and 3 flavins * are the excited singlet and triplet states of the flavins, respectively. The degradation mechanisms of these photoinduced flavins were likely initiated by a triplet−triplet annihilation or a triplet–ground state quenching process [25,31,32,33], the latter of which is depicted in this study. The TC directly oxidized by an electron abstraction through an electron transfer event from the TC ground state was started via flovin-sensitised irradiation [25].…”