Reactions of Excited Triplet Duroquinone with .alpha.-Tocopherol and Ascorbate: A Nanosecond Laser Flash Photolysis and Time-Resolved Resonance Raman Investigation

Phenols as Antioxidants

“…Product distribution using chemical oxidizing agents, such as metal ions, will therefore give different products and one must be careful in assuming that these are also typical of the products from free radical oxidation of these chromanols in non-polar solvents. As has been emphasized before 18 , α-Toc and related phenols owe their effective antioxidant activity to the rapid reaction with peroxyl radicals (equations 10 and 11), and the ArO ž 'wasting' reactions (equations [18][19][20][21] are all relatively slow reactions. …”

“…However, phenoxyl radicals, particularly unhindered ones, are also able to participate in chain transfer reactions by hydrogen atom abstraction from hydroperoxides which build up (equation 21), which is the reverse of equation 10, or initiate new reaction chains by hydrogen atom abstraction from substrate (R s H) (equation 20).…”

Amino Acids, Lactic Acid and Ascorbic Acid as Raw Materials for Biocompatible Surfactants

“…This feature is particularly important in order to determine the mutual miscibility of ascorbic acid derivatives and some relevant natural compounds with a perspective of producing stabilized systems where the ascorbyl derivative protects the other components against oxidation. Several studies [124][125][126][127] have shown that the association of ascorbic acid derivatives and tocopherols enhances the antioxidant capability of the two vitamins. The ascorbic acid derivatives/tocopherol mixtures are therefore a very promising and important tool for the stabilization and protection of many different systems, such as biological materials, food and artificial membranes used as drug carriers, from both the scientific and industrial points of view.…”

Quenching dynamics study on photoinduced excited triplet duroquinone by TEMPO in 1,2-propandiol

“…Xu and nonenzymatic redox cycling [3], may produce damage in biological systems either directly by electron or hydrogen atom from cellular proteins or indirectly by acting as sensitizers of singlet oxygen [4][5][6]. The investigations on the photochemical reaction of quinones and the quenching of triplet quinones have been of great interest for a long time [7][8][9][10][11].…”