Biol. Pharm. Bull., 28(5),808-810, May 2005

Regular Articles

Hypnotic Activities of Chamomile and Passiflora Extracts in Sleep-Disturbed Rats

Kazuaki SHINOMIYA,^a Toshio INOUE,^b Yoshiaki UTSU,^a Shin TOKUNAGA,^a Takayoshi MASUOKA,^a Asae OHMORI,^a and Chiaki KAMEI,^*,a

^a Department of Pharmacology, Faculty of Pharmaceutical Sciences, Okayama University; 1-1-1 Tsushima-naka, Okayama 700-8530, Japan: and ^b Material R&D Laboratory, Ogawa & Co., Ltd.; 15-7 Chidori, Urayasu, Chiba 279-0032, Japan. * To whom correspondence should be addressed. e-mail: kamei@pheasant.pharm.okayama-u.ac.jp

In the present study, we investigated hypnotic activities of chamomile and passiflora extracts using sleep-disturbed model rats. A significant decrease in sleep latency was observed with chamomile extract at a dose of 300 mg/kg, while passiflora extract showed no effects on sleep latency even at a dose of 3000 mg/kg. No significant effects were observed with both herbal extracts on total times of wakefulness, non-rapid eye movement (non-REM) sleep and REM sleep. Flumazenil, a benzodiazepine receptor antagonist, at a dose of 3 mg/kg showed a significant antagonistic effect on the shortening in sleep latency induced by chamomile extract. No significant effects were observed with chamomile and passiflora extracts on delta activity during non-REM sleep. In conclusion, chamomile extract is a herb having benzodiazepine-like hypnotic activity.

Key words chamomile; passiflora; insomnia; herbal drug; sleep-disturbed model; rat