3. NMRおよび量子化学計算によるトレハロースの抗酸化作用の研究(第49回低温生物工学会研究報告)

概要

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Here we report on the mechanism of antioxidant function of trehalose for unsaturated fatty acids (UFAs). The spin-lattice relaxation times (T_1) of ^1H and ^<13>C NMR spectra are measured to investigate the interaction between trehalose and UFAs. It is found that for the ^1H and ^<13>C signals assigned to the olefin double bonds in UFA, the T_1 values decrease with increasing concentration of trehalose and the change reaches a plateau at an integer molar ratio of trehalose/UFA. Such T_1 changes are found only for mixed systems of trehalose and UFAs possessing cis double bond (s). Similar experiments are performed for other sugar/UFA mixtures, but no apparent T_1 changes were observed for the UFA protons. In addition, it is suggested from the ^<13>C-T_1 measurements that the OH-6'(OH-6) and OH-3 (OH-3') hydroxyl groups of trehalose are responsible for the interaction with UFAs. Computer modeling study indicates that trehalose forms a stable complex with an olefin double bond through OH…π and CH…O types of hydrogen bonding. Furthermore, a significant increase in the activation energy is found for hydrogen abstraction reaction from the activated methylene group of UFA. Therefore, these results indicate that one trehalose molecule stoichiometrically interacts with one cis-olefin double bond of UFA and hence it has a significant depression effect on the oxidation of UFA.
低温生物工学会の論文
2003-12-30