Plum juice, but not dried plum powder, is effective in mitigating cognitive deficits in aged rats

Abstract

Objective Normal aging in animals and humans is accompanied by a decline in cognitive performance that is thought to be due to the long-term effects of oxidative stress and inflammation on neurologic processes. Previous findings have suggested that protection against age-related cognitive declines may be achieved by increasing the dietary intake of fruits and vegetables, especially those that are high in antioxidant activity, such as blueberries and strawberries. The objective of this study was to investigate supplementation with Prunus domestica L. in mitigating age-related deficits in cognitive function. Methods We investigated the effects of supplementation with P. domestica L., consumed as a 2% dried plum (i.e., prune) powder or 100% plum juice for 8 wk, in mitigating age-related deficits in cognitive function in aged Fischer 344 rats. Results Rats that drank plum juice from 19 to 21 mo of age had improved working memory in the Morris water maze, whereas rats fed dried plum powder were not different from the control group, possibly due to the smaller quantity of phenolics consumed in the powder group compared with the juice group. Conclusion These results are discussed in relation to the amount and type of phenolics present in the plum products and in relation to other dietary intervention studies in which cognitive benefits have been reported.