Hastatoside and verbenalin are sleep-promoting components in Verbena officinalis

Herbal tea made from Verbena officinalis (V. officinalis) has traditionally been used for the treatment of insomnia and other nervous conditions. In this study, we examined the sleep-promoting activity of hastatoside, verbenalin, and verbascoside, which are the major iridoids (hastatoside and verbenalin) and polyphenol (verbascoside) components responsible for the pharmacological activity of V. officinalis, by electroencephalographic analysis of rats after oral administration of the compounds. Hastatoside (0.64 mmol/kg of body weight) and verbenalin (1.28 mmol/kg of body weight) increased the total time of non-rapid eye movement sleep during a 9-h period from 23.00 to 08.00 hours by 81% and 42%, respectively, with a lag time of about 3-5 h after the administration at 20.00 hours (lights-off time). Both compounds also increased the delta activity during non-rapid eye movement sleep. However, verbascoside had no effect on the amount of sleep. Therefore, hastatoside and verbenalin are major sleep-promoting components of V. officinalis.