辐射引发的亚油酸和亚麻酸自由基产物及α-生育酚的辐射保护效应的ESR研究  

ESR STUDIES OF RADIATION INDUCED RADICAL PRODUCTS FROM LINOLEIC ACID AND LINOLENIC ACID AND THE RADIOPROTECTIVE EFFECT BY α-TOCOPHEROL

作　　者：朱幼南[1] 屠铁城[1] 董继荣 张加山[1] 林念芸[1] 

机构地区：[1]中国科学院上海原子核研究所,上海201800

出　　处：《辐射研究与辐射工艺学报》1993年第1期1-6,共6页Journal of Radiation Research and Radiation Processing

基　　金：国家自然科学基金

摘　　要：用电子自旋共振波谱法,对在含氧条件下经过低温γ辐照的不饱和脂质亚油酸和亚麻酸产生的初级不稳定自由基,及其在程序升温过程中所产生的自由基变化进行了研究。由77K辐照并测定的ESR谱表明其初级不稳定产物为阴离子自由基和脂质长链上不饱和部分的抽氢自由基,在120 K附近所测得的ESR谱显示了脂质过氧自由基的波谱特征,随着温度继续上升,最后演变为戊二烯基自由基和α-碳抽氢自由基。亚油酸和亚麻酸与α-生育酚(摩尔比1:1)二元体系的ESR研究,揭示了α-生育酚对亚油酸和亚麻酸的辐射保护作用是基于氢原子转移机理。Primary radicals from the γ-radiolysis of air-saturated linoleic acid and linolenic acid at 77 K, and the subsequent sccondary radicals appeared during thecourse of variable temperature elevation were investigated by ESR. The ESR spectrumfrom samples irradiated and observed at 77 K shows the presence of the radical aniondoublet arised from the electron adducts of the carboxygroups and the poorly resol-ved broad singlet results from some carbon-centered radicals. Annealing to approxi-mately 125 K which allow for molecular oxygen migration results in the formationof peroxyl radicals. At 247 K, the ESR spectrum is a multi-line pattern which isattributable to structure of the α-carbon radical superimposed on the pentadienyl ra-dicals. The ESR spectra from linoleic acid-----α-tocopherol and linolenic acid----α-tocopherol binary systems irradiated at 77 K and recorded at 140 K or 215 K revealedhe characteristic similarity to that from α-tocopherol alone, no trace of ESR signalfrom either peroxyl or t composite pattern from superposition of pentadienyl radical and α-carbon radicals can be found out. Therefore α-tocopherol has exerted ra-dioprotection effect on peroxidation of linoleic acid and linolenic acid.

关 键 词：亚油酸 亚麻酸 自由基 辐射 保护 

分 类 号：Q691.2[生物学—生物物理学]