Acori graminei Rhizoma (AGR), the dry rhizomes of Acorus gramineus SOLANDER

Acorus gramineus SOLANDER (Araceae), is officially listed in the Korean Pharmacopoeia which records its sedative, digestive, analgesic, diuretic, and antifungal effects. This herbal drug has been reported to be responsible for various pharmacological actions on the central nervous system (CNS): The water extract or methanol extract of AGR antagonized pentylenetetrazole-induced convulsion, potentiated pentobarbital-induced sleeping time, induced sedation, and decreased spontaneous activity in mice. Receptor-ligand binding studies suggested that the interactions with the central dopamine receptors and the GABAA-benzodiazepine receptor mediate these central inhibitory actions. Besides that, the extracts of composite drugs containing AGR as a main component are clinically used for improvement of learning and memory and for stroke. However, the essential oil of AGR has not been thoroughly evaluated. Recently we reported that this oil inhibited glutamate-induced excitotoxicity in a concentration-dependent manner, leading to neuroprotective effects on cultured cortical neurons through the blockade of NMDA receptor activity, and exhibited antioxidative effects in in vivo and in vitro assay. The rhizomes and leaves of Acorus gramineus are known to contain 0.11—0.42% of essential oil consisting of 30 kinds of compounds which may affect the CNS after direct inhalation of its fragrance. Pure fragrance compounds and essential oils with sedative properties influenced the motility of mice in inhalation studies under standardized conditions. To date, only a few papers have reported on sedative or activating properties of some essential oils and their constituents on animals under standardized experimental procedures. We now report the effects of an essential oil of AGR on the sedative and anticonvulsant properties and also antioxidative activity after fragrance inhalation.