Distribution of α-asarone in brain following three different routes of administration in rats.

The goal of the present paper is to compare the distributions of α-asarone administered to rats through three different routes: oral, intravenous and intranasal. The concentrations of α-asarone in seven distinct brain regions, the olfactory bulb, cerebellum, hypothalamus, frontal cortex, striatum, hippocampus and medulla/pons as well as in plasma and cerebrospinal fluid (CSF), were determined by HPLC. The quantities of α-asarone accumulated in liver were measured to determine whether α-asarone could generate hepatotoxicity when administered via the three different routes. The results indicated that α-asarone could be absorbed via two different routes into the brain, after intranasal administration of dry powders. In the systemic route, α-asarone immediately entered the brain through the blood-brain barrier (BBB) after uptake into the circulatory system. In the olfactory bulb route, α-asarone traveled from the olfactory epithelium in the nasal cavity straight into brain tissue via the olfactory bulb. Furthermore, intranasal administration of α-asarone as a dry powder can ensure quick absorption and avoid excessive concentrations in the blood and liver, while achieving concentrations in the brain comparable to those attained by intravenous and oral administration routes.