Protective, Preventive and Enhancing-Memory Effects of the Flavonoidic-Rich Plants or Flavonoidic Molecules: Behavioural, Neurochemical and Pharmacological Correlates

Abstract

Our group has focused on understanding the putative neuromodulatory effects of flavonoidic-rich plants or flavonoidic molecules. This mini-review summarizes the effects of these substances on fear memory and anxiety in adult and middle-aged rats Multiple-dosing schemes, different behavioral procedures and different time points of treatment have provided direct evidence of the modulatory effects of these molecules upon the acquisition and extinction of conditioned suppression. This has enabled us to further evaluate short-and longterm memory. To better understand the effects of standardized extract of Ginkgo biloba (EGb) or of Flavonoidic fraction (FfB) on fear memory, we conducted both pharmacological and molecular analysis. The dose-dependent effects observed after EGb or FfB treatments on the conditioned fear include the spontaneous recovery of fear memory. FfB reversed the effect of blocking of GluN2B subunits of N-methyl-D-Aspartate receptor (GluN2B-NMDARs) on conditioned suppression. These results turned our attention to the therapeutic relevance of these data, as the pharmacological agents that enhance the acquisition/consolidation of fear memory or fear extinction might serve as an adjunct to the treatment of memory decline or anxiety disorders. In addition, the molecular results provided important information regarding the role of the dorsal hippocampal formation (dHF) on conditioned suppression and as a possible target to potential drug therapy. Additionally, we evaluated the effects of EGb on short and long term-memory in middle-aged rats submitted to the plus maze discriminative avoidance task (PM-DAT) as well as upon the level of DNA damage of Prefrontal cortex (PFC) and dHF. All together, these findings appear to support and extend the view that flavonoids are cognitive enhancers.