Facile method for spectroscopic examination of radical ions of hydrophilic carotenoids

Starch Can Inhibit Nitrite-Dependent Oxidation of Crocin in Gastric Lumen Increasing Bioavailability of Carotenoids

“…Formation of carotenoid radicals, including crocin radicals, by oxidation has been reported (Bors et al, 1982;Naqvi et al, 2009). The radicals would react each other rapidly to produce products that have no absorption bands in the waveis composed of crocetin (molecular weight = 382), to which two molecules of gentiobiose (molecular weight = 342.30) are bound (Fig.…”

Synthesis of a Highly Unsaturated, Stable Hydroxy Peroxide: A Yellow [lrarr2] Blue Color‐Changing Carotenoid Oxidation Product with Leuco Dye Properties

“…Since iron and oxygen are constant companions of carotenoids [40] possible biochemical effects could be imagined. Further efforts in elucidation the intricate mechanistic aspects of chemically generated carotenoid ion radicals and by-products are warranted in line with similar photochemical, [3,41] radiolytical [2] and electrochemical [39,42] studies. Preliminary experiments with C20-C35 ester (5-11 double bonds) show all immediate electron transfer to FeCl 3 whatever the oxidation potential of the carotenoids (E°= 1.05-0.63 V), [43] though the decay pattern to final products is more ambiguous than with Car (C30-ester, 9 double bonds).…”

Facile Electron Uptake by Carotenoids Under Mild, Non‐Radiative Conditions: Formation of Carotenoid Anions

“…[11,15,17] We have not been able to detect short-lived Car ·-2 by its NIR absorption ( Figure 1). [18] Therefore, the prompt appearance of Car 2-3 suggests either a direct two electron uptake, a rapid, successive one-electron attachment or a single electron uptake followed by an immediate disproportionation reaction 2 Car ·-Ǟ Car 2-+ Car. [14] A probable dimerisation 2 Car ·-Ǟ Car-Car 2-has been excluded.…”

“…sBuLi), [14] electrochemical methods, [15] ionizing rays (pulse radiolysis) [2,16,17] and flash photolysis. [18] Notwithstanding, electron transfer to Car should be possible without relying on particular scrupulous procedures. The methylsulfinylmethide (dimsyl) anion H 3 CS(=O)CH 2 -(DMSO -), prepared from DMSO with alkali (sBuOK, KOH), [19] is not only a powerful base and nucleophile but also a reducing agent.…”