Adzuki bean (Vigna angularis) extract reduces amyloid-β aggregation and delays cognitive impairment in Drosophila models of Alzheimer's disease

BACKGROUND/OBJECTIVES: Alzheimer's disease is a neurodegenerative disease that induces symptoms such as a decrease in motor function and cognitive impairment. Increases in the aggregation and deposition of amyloid beta protein (Aβ) in the brain may be closely correlated with the development of Alzheimer's disease. In this study, the effects of an adzuki bean extract on the aggregation of Aβ were examined; moreover, the anti-Alzheimer's activity of the adzuki extract was examined. MATERIALS/METHODS: First, we undertook thioflavin T (ThT) fluorescence analysis and transmission electron microscopy (TEM) to evaluate the effect of an adzuki bean extract on Aβ42 aggregation. To evaluate the effects of the adzuki extract on the symptoms of Alzheimer's disease in vivo, Aβ42-overexpressing Drosophila were used. In these flies, overexpression of Aβ42 induced the formation of Aβ42 aggregates in the brain, decreased motor function, and resulted in cognitive impairment. RESULTS: Based on the results obtained by ThT fluorescence assays and TEM, the adzuki bean extract inhibited the formation of Aβ42 aggregates in a concentration-dependent manner. When Aβ42-overexpressing flies were fed regular medium containing adzuki extract, the Aβ42 level in the brain was significantly lower than that in the group fed regular medium only. Furthermore, suppression of the decrease in motor function, suppression of cognitive impairment, and improvement in lifespan were observed in Aβ42-overexpressing flies fed regular medium with adzuki extract. CONCLUSIONS: The results reveal the delaying effects of an adzuki bean extract on the progression of Alzheimer's disease and provide useful information for identifying novel prevention treatments for Alzheimer's disease.

Nodulation and N2 fixation effectiveness of Bradyrhizobium strains in symbiosis with Adzuki Bean, Vigna angularis

In pot experiment, one isolate Knj from a Serbian soil, four strains of Bradyrhizobium japonicum and three strains of Bradyrhizobium spp. were examined for the effect on adzuki bean nodulation and effectiveness in symbiotic N2 fixation. All the tested strains produced root nodules in adzuki bean. Strains of B. japonicum showed high potential of N2 fixation, particularly 525 and 542. B. japonicum strains resulted 65-71 percent shoot dry weight and 99-138 percent total N content of uninoculated control with full N content (100 percent). No significant difference was found between the plants inoculated with Bradyrhizobium spp. strains and uninoculated control plants without N (40-42 and 42 percent shoot dry weight, respectively), which indicated symbiotic N2 fixation inactivity of the Bradyrhizobium spp. strains. Knj strain had the middle position (56 percent shoot dry weight). These data showed that B. japonicum 525 and 542 strains could be used in further investigations in order to apply them as inoculants in microbiological N fertilizers.