Blood Levels of 1,8-Cineole and Locomotor Activity of Mice After Inhalation and Oral Administration of Rosemary Oil¹

Abstract

One hour after the addition of 0.5 ml rosemary oil per cage for evaporation (141 of volume) the concentration of 1,8-cineole in the blood, 11.15 nl/g, approached that in the breathing air, 13.65 nl/ml. Inhalation and oral administration of various doses of rosemary oil produced dose-related increases in blood levels of 1,8-cineole. An increase in locomotor activity was observed in both cases. The disappearance of 1,8-cineole from the blood immediately after the termination of a 60-min inhalation period was biphasic: a rapid phase of elimination of about 10 min with a short blood half life (t/2 = 6 min) was followed by a slower rate of elimination (t/2 = 45 min).

Since the blood levels of 1,8-cineole (if taken as an indicator for the blood levels of rosemary oil) associated with the stimulation of locomotor activity were similar regardless of whether the oil was administered by inhalation or orally, it is suggested that the stimulation of locomotor activity by rosemary oil is due at least in part to the direct pharmacological action of one or more of its constituents.