Electrophysiological Characterization of Neurotropic Activity of Sideritis Tea Volatiles

Sideritis spp. is a member of the Labiateae plant family, and used for tea infusions with claimed sedative properties. To clarify if the volatile fractions of the plant material can exert a sedative effect via g-aminobutyric acid (GABA) signaling, a dichloromethane (DCM) aroma extract of the aerial parts was prepared. The volatile fraction was separated via solvent assisted flavor evaporation (SAFE) distillation. In electrophysiological recordings using the two-electrode voltage clamp technique (TEVC), the plant extract of Sideritis species showed potentiation effects of the maximal GABA-induced response on GABAA receptors comparable to those of lavender.