Abstract
Background Silexan, a special essential oil from flowering tops of
lavandula angustifolia, is used to treat subsyndromal anxiety disorders. In
a recent clinical trial, Silexan also showed antidepressant effects in
patients suffering from mixed anxiety-depression (ICD-10 F41.2). Since
preclinical data explaining antidepressant properties of Silexan are
missing, we decided to investigate if Silexan also shows antidepressant-like
effects in vitro as well as in vivo models.
Methods We used the forced swimming test (FST) in rats as a simple
behavioral test indicative of antidepressant activity in vivo. As
environmental events and other risk factors contribute to depression through
converging molecular and cellular mechanisms that disrupt neuronal function
and morphology—resulting in dysfunction of the circuitry that is
essential for mood regulation and cognitive function—we investigated
the neurotrophic properties of Silexan in neuronal cell lines and primary
hippocampal neurons.
Results The antidepressant activity of Silexan
(30 mg/kg BW) in the FST was comparable to the tricyclic
antidepressant imipramine (20 mg/kg BW) after 9-day
treatment. Silexan triggered neurite outgrowth and synaptogenesis in 2
different neuronal cell models and led to a significant increase in
synaptogenesis in primary hippocampal neurons. Silexan led to a significant
phosphorylation of protein kinase A and subsequent CREB phosphorylation.
Conclusion Taken together, Silexan demonstrates antidepressant-like
effects in cellular as well as animal models for antidepressant activity.
Therefore, our data provides preclinical evidence for the clinical
antidepressant effects of Silexan in patients with mixed depression and
anxiety.
Key words
lavender - synaptic plasticity - CREB - antidepressant effects - neurite outgrowth
