Abstract
In this study, a process of peroxidation of linolenic acid, which is one of fatty acids that is the simplest biological lipid, by gamma-irradiation was analyzed. The linolenic acid was dissolved in benzene at a final concentration of 1 mM. The linolenic acid micelle was prepared as follows. The linolenic acid at a final concentration of 1 mM was added to PBS(-) with 0.08% nonaethylene glycol monododecyl ether. And, this solution was stirred vigorously. The prepared solutions were irradiated with 60Co gamma-rays at several dose-rates. Gamma-irradiated sample solution was combined with TBA regent and mixed thoroughly. The mixed solution was heated for 15 min in a boiling water bath. The malondialdehyde (MDA) amount was determined by measuring the absorbance of the reaction solution at 532 nm. In this study, the lipid peroxidation was evaluated by the MDA amount. The lipid peroxidation of linolenic acid progressed with increasing dose of gamma-irradiation in benzene. It was revealed that this dose-effect relationship was nonlinear. In this experimental condition, there was a inverse dose-rate effect. In linorenic acid micelle solution, a relative MDA amount value increased linearly with increasing dose of gamma-irradiation up to 0.5 kGy (dose rate: 0.8 kGy/h). In dose of gamma-irradiation more than 0.5 kGy, a relative MDA amount value decreased dose-dependently and gradually. Difference between dose-effect relationship in a linolenic acid micelle solution and that in a linolenic acid benzene solution shows that the molecular environment of linolenic acid affects the linolenic acid peroxidation by gamma-irradiation.
