Combination of Vitamin E with a Carotenoid:α-Tocopherol and Trolox Linked toβ-Apo-8′-carotenoic Acid

Abstract

Vitamin E and carotenoids show many similar and complementary properties and protect living tissues against a variety of pathological processes. A mixture of both compounds often exhibits a significantly greater effect than the sum of the individual activities. The synthetic linkage of carotenoids with vitamin E might thus increase the synergistic effects. We therefore esterified b-apo-8'-carotenoic acid with all-rac-a-tocopherol to give atocopheryl-b-apo-8'-carotenoate. The carotenoic acid was also connected to a-tocopherol in a glyceride ether, 1-O-(a-tocopheryl)-3-(b-apo-8'-carotenoyl)-glycerol, whereas the water-soluble vitamin E analogue, trolox, was combined with b-apo-8'-carotenoic acid in a diglyceride: 1-(6-hydroxy-2,5,7,8-tetramethylchroman-2-acyl)-3-(b-apo-8'-carotenoyl)-glycerol.

Kinetic Method for Determining Antioxidant Distributions in Model Food Emulsions: Distribution Constants of t-Butylhydroquinone in Mixtures of Octane, Water, and a Nonionic Emulsifier

“…The problem is exacerbated in organized systems, such as homogeneous aqueous micelles and microemulsions and biphasic emulsions, because the overall effectiveness of antioxidants also depends on the concentrations of the reactive components in the different regions in the system, that is, the aqueous and oil regions and the interfacial region composed of the surfactant film layered at the boundary between the aqueous and oil regions (3,4,5). Much progress has been made, but additional complexities still exist including fully understanding prooxidant (10)(11)(12)(13) and synergistic activity (14,15).…”

Synthesis of all‐trans‐[10′‐3H]‐8′‐apo‐β‐carotenoic acid

“…Hydrolysis of ethyl ester 10 proved to be more challenging than expected and routine basic and acidic conditions did not lead to a high yielding process. However, procedures detailed by a recent report by Larsen et al 41 for hydrolysis of such esters was used successfully (see experimental) to obtain the radiolabeled acid 3 (21 mCi/mmol) in 19% overall radiochemical yield. With 3 in hand, we are presently in the process of optimizing photoaffinity labeling conditions.…”

“…The crude product was purified through a small pad of silica in a Pasteur pipet (5-15% ethyl acetate in hexane) to yield pure acid 3 (7.0 mg, 80%, 21 mCi/mmol, 0.34 mCi, 19% of total radionuclei incorporated) based on comparative TLC, and UV with authentic cold material, and all spectroscopic data were consistent with reported values. 41 UV: l max (acetone) 440 nm; 1…”

Key to Xenobiotic Carotenoids

“…It would furthermore be valuable to have at hand a complete directory of isotope-substituted carotenoids (D, T, 13 C, 14 C) [38,39,40]. A catalog of modified carotenoids (e.g., long chain carotenoids, carotenoid dimers, carotenoids with deviated conjugation, hydrophilic carotenoids) and of compounds where carotenoids are part of other molecule classes (e.g., carotenoid lipids, antioxidant combinations) would likewise be desirable [41,42,43,44,45,46,47,48,49,50,51].…”