Prunella vulgaris var. lilacina Enhances Cognitive Performance Through Up-Regulation of Hippocampal Neurogenesis

Adult hippocampal neurogenesis is a pivotal role in neuronal plasticity that is critically involved in cognitive function and neurological disease. We recently suggested that the ethanolic extract of Prunella vulgaris var. lilacina (EEPV) may be used for the prevention and treatment of cognitive impairments associated with Alzheimer's disease or schizophrenia. We hypothesized that EEPV promotes adult neurogenesis, which may be beneficial to hippocampus-dependent learning and memory. We showed that sub-chronic administration EEPV for 14 days significantly increased cell proliferation measured by 5-bromo-2'-deoxyuridine (BrdU) or doublecortin in the dentate gyrus of adult mice. Moreover, sub-chronic administration EEPV for 14 days markedly improved cognitive function in the passive avoidance task. These effects may be associated with various signaling molecules including ERK-CREB, Akt-GSK-3β or CaMKII in the hippocampus. In addition, chronic administration of EEPV for 28 days significantly increased NeuN+BrdU-labeled cells in the hippocampus and enhanced cognitive function in mice, which indicates that EEPV promotes neuronal cells survival. Our results also indicate that EEPV enhances cognitive performance via up-regulation of adult hippocampal neurogenesis.