Effects of anthocyanins on active avoidance test of rats exposed to disruption of diurnal rhythm

The present study was undertaken to assess the effects of the natural antioxidant anthocyanins on learning and memory of rats in experimental model of oxidative stress. Our preliminary experiments demonstrated that disruption of diurnal rhythm via exposition of rats to constant light for 14 days caused excessive generation of free radicals in their brains. It is known that free radicals impair cognitive functions. This study investigated the effects of anthocyanins on cognitive functions of rats in a shuttle-box active avoidance test. In the shuttle-box, stressed rats showed significantly increased latency time and decreased number of avoidances and escapes in the learning sessions. Rats treated with anthocyanins had increased number of avoidances and escapes and significantly decreased latency time during the learning sessions. Our results demonstrated that this model of oxidative stress impaired learning and memory of experimental rats. Moreover, chronic administration of anthocyanins (200 mg/kg orally) improved brain functions of the rats. Our data suggest that anthocyanins have a protective role on rat brain and improve cognitive functions in this model of oxidative stress.