Study on the opening effect of eucalyptol on the blood–brain barrier and its brain pharmacokinetics

Abstract

Eucalyptol, a natural epoxide monoterpene, was found in rat brain tissue after oral administration in our previous study, suggesting that the compound may possess the ability to pass the blood–brain barrier (BBB). However, a few studies have demonstrated that eucalyptol does penetrate the BBB. The aims of this study were to determine the opening effect of eucalyptol on the BBB in rats, to establish and validate a method for the determination of eucalyptol in brain tissue, and to reveal its brain pharmacokinetic characteristics. The opening effect of BBB was assessed by dye extravasation and ultrastructural alterations, and the quantitative method of eucalyptol in rat brain tissue was established and confirmed. For pharmacokinetic research, rat brain samples were taken at 0.05, 0.167, 0.5, 1, 2.5, 5, 10, and 15 h after administration. There was a significantly higher extravasation of Evans blue from the brain parenchyma of rats in the medium‐dose eucalyptol group (P < 0.01), which was associated with the BBB's altered ultrastructure. It is suggested that eucalyptol increased the permeability of the BBB. After oral administration, eucalyptol was quickly absorbed by the brain. This study provides valuable information on eucalyptol use to treat illnesses of the central nervous system.

Modes of Action of 1,8-Cineol in Infections and Inflammation

“…The decreased activity of GSK-3 in response to 1,8-Cineol could ameliorate advanced glycation end products, which can be identified by immunohistochemistry in the senile plaques and neurofibrillary tangles of Alzheimer’s disease [ 86 , 87 ]. In this context, it was recently shown that eucalyptol reveals an opening effect on the blood–brain barrier and thus provides a promising addition in the treatment of illnesses of the central nervous system and its brain pharmacokinetics [ 88 ].…”

Assessment of the Anti-Amyloidogenic Properties of Essential Oils and Their Constituents in Cells Using a Whole-Cell Recombinant Biosensor

“…Apart from their ability to cross the blood-brain barrier [96,97], the fact that linalool and eucalyptol can be taken orally has an added value, as there is now increasing evidence that α-syn pathology appears in the gastrointestinal tract and enteric nervous system well before it makes its entrance in the brain [98]. In vivo studies of citron and sage essential oils, along with their primary components, linalool and eucalyptol, are the next logical step for further assessment of their anti-amyloidogenic properties.…”