Dracocephalum moldavica attenuates scopolamine-induced cognitive impairment through activation of hippocampal ERK-CREB signaling in mice

Dracocephalum moldavica (Moldavian balm) has been traditionally used for the treatment of intellectual disabilities, migraines and cardiovascular problems in East Asia. Recent scientific studies have demonstrated the usefulness of this plant to treat neurodegenerative disorders, including Alzheimer's disease. This study aimed to investigate the effects of the ethanolic extract of D. moldavica leaves (EEDM) on scopolamine-induced cognitive impairment in mice and the underlying mechanisms of action. The behavioral effects of EEDM were examined using the step-through passive avoidance and Morris water maze tasks. To elucidate the underlying mechanism, we tested whether EEDM affects acetylcholinesterase activity and the expression of memory-related signaling molecules including extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB) in the hippocampus. EEDM (25, 50 or 100 mg/kg) significantly ameliorated the scopolamine-induced step-through latency reduction in the passive avoidance task in mice. In the Morris water maze task, EEDM (50 mg/kg) significantly attenuated scopolamine-induced memory impairment. Furthermore, the administration of EEDM increased the phosphorylation levels of ERK and CREB in the hippocampus but did not alter acetylcholinesterase activity. These findings suggest that EEDM significantly attenuates scopolamine-induced memory impairment in mice and may be a promising therapeutic agent for improving memory impairment.