Reduction of the chronic stress response by inhalation of hiba (Thujopsis dolabrata) essential oil in rats.

To verify the effects of hiba essential oil in restrained stressed rats, we analyzed physiological variables and psychophysiological behavior. Stressed-HEO rats inhaled hiba essential oil aroma after restraint period. The quantities of food and water intake and the excretion amount of stressed rats were smaller than those of non-stressed control rats. Body weights of stressed rats decreased compared with those of control rats. These physiological variables of stress-HEO rats significantly recovered compared with those of stressed rats (P < 0.001). Stress-related anxiety was assessed using the elevated plus-maze test. Entry times into the open arms of stressed rats were less than those of control rats (P < 0.05). In contrast, the suppression of entry times into the open arms of stressed rats was restored by the inhalation of hiba oil. The results suggest that hiba essential oil inhalation reduced stress-induced growth inhibition and stress-related anxiety.