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A Pulse Radiolysis Study of the Dynamics of Ascorbic Acid Free Radicals within a Liposomal Environment |
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| Authors: | Dr Kazuo Kobayashi Yumiko Seike Dr Akinori Saeki Prof Takahiro Kozawa Dr Fusako Takeuchi Prof Motonari Tsubaki |
| Institution: | 1. The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8‐1, Ibaraki, Osaka (Japan);2. Department of Life Science, Faculty of Science, Himeji Institute of Technology, (presently) University of Hyogo, Kamigori‐cho, Akou‐gun, Hyogo 678‐1297 (Japan);3. Graduate School of Engineering, Osaka University, 2‐1 Yamadaoka, Suita, Osaka (Japan);4. Institute for Promotion of Higher Education, 1‐2‐1 Tsurukabuto, Nada‐ku, Kobe, Hyogo 657‐8501 (Japan);5. Kobe University, Graduate School of Science, Department of Chemistry, 1‐1 Rokkodai‐cho, Nada‐ku, Kobe, Hyogo 657‐8501 (Japan) |
| Abstract: | The dynamics of free‐radical species in a model cellular system are examined by measuring the formation and decay of ascorbate radicals within a liposome with pulse radiolysis techniques. Upon pulse radiolysis of an N2O‐saturated aqueous solution containing ascorbate‐loaded liposome vesicles, ascorbate radicals are formed by the reaction of OH. radicals with ascorbate in unilamellar vesicles exclusively, irrespective of the presence of vesicle lipids. The radicals are found to decay rapidly compared with the decay kinetics in an aqueous solution. The distinct radical reaction kinetics in the vesicles and in bulk solution are characterized, and the kinetic data are analyzed. |
| Keywords: | ascorbate liposomes nanospace pulse radiolysis radicals |