Oxidative stress in the pathogenesis of Alzheimer's disease: Improvement of memory-deteriorating disease by administration of plant enzyme

Plant enzymes are natural substances with almost no side effects and reported effects on spatial learning and histopathological alterations of the hippocampus in senescence-accelerated mice. In senescence-accelerated mice (SAMP8), this in vivo study examined the effects of a plant enzyme on the brain hippocampus, memory and spatial cognition. In the Morris water maze, a comparison between the control group of SAMR1 mice and the sham control group of SAMP8 mice (SAMP8 without plant enzymes administration) showed a significant reduction in arrival time, and in the probe test, it was divided into 4 divisions. Moreover, there was a significant increase in dwell time and number of crossings of the virtual platform area. The plant enzyme-treated group tended to have a shorter arrival time than the sham group, but not significantly different. Serum peroxy radicals were significantly suppressed in the plant enzyme-treated group compared with the sham group. Plant enzyme inhibited the peroxy radical in comparison to a sham control. With plant enzymes treatment, the lipid peroxidation level was significantly lowered in the brain tissue compared with the sham control group (p < 0.05. Serotonin (5-HT) levels were significantly higher in the brain tissue of plant enzymes -treated mice than in that of sham control mice. There was no significant difference in the brain lipid peroxide concentration between the plant enzyme administration group and the sham group. In contrast, the serotonin concentration in the brain was significantly different between the plant enzymes administration group and the sham control group. The high neuron density (CA1 region) in the hippocampus of animals in the plant enzymes administration group indicates a possible improvement in memory.