Remarkable enhancement of antioxidant activity of vitamin C in an artificial bilayer by making it lipo-soluble
✍ Scribed by Xiao-Yang Liu; Feng-Li Guo; Lung-Min Wu; You-Cheng Liu; Zhong-Li Liu
- Book ID
- 103038464
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 353 KB
- Volume
- 83
- Category
- Article
- ISSN
- 0009-3084
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✦ Synopsis
The reaction kinetics between 4-palmitoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO-16) and vitamin C (VC) and its lipophilic derivative ascorbyl-6-palmitate (VC-16) was studied by stopped-flow ESR spectroscopy in a synthetic surfactant vesicle sodium 1-pentadecyl hexadecyl sulfate (SPHS). TEMPO-16 reacted with VC very slowly and showed a biphasic first-order kinetics with rate constants of 9.6 x 10(-4) and 2.5 x 10(-4) s-1, corresponding to diffusion of TEMPO-16 from the external monolayer of SPHS to the bulk water and flip-flop of TEMPO-16 from the internal to external monolayer of the vesicle, respectively. On the other hand, the reaction of TEMPO-16 with VC-16 was second-order and over three orders of magnitude faster than that with VC, presumably due to VC-16 induced fusion of the vesicle.