Background: N-alkylamides (NAAs), a large group of secondary metabolites occurring in more than 25 plant families, are potential drug candidates as several biological and medical functions are known such as central nervous activities [1].
Objective: Our general goal was to investigate if NAAs with a different structure, e.g. spilanthol and pellitorine, are able to pass the blood-brain barrier (BBB) and if so, to what extent.
Methods: A blood to brain (multiple time regression (MTR)), as well as a brain to blood (efflux) transport experiment were conducted in an in vivo mice model to investigate the initial BBB rate kinetics. The mice were anesthetized, after which the NAA dose solution was injected. Blood was obtained at regular time points after injection, and thereafter, the mice were decapitated and the brains collected. Quantification of the NAAs was done using a bio-analytical LC-MS method.
Results: The MTR experiment indicated that spilanthol was able to cross the BBB in mice. A rapid but highly significant influx of spilanthol into the brains was observed with an unidirectional influx rate of 217.0 µl/(g×min). The curve reached a plateau-phase after about 10 minutes exposure time and can be explained by efflux of spilanthol out of the brain or distribution or elimination of spilanthol. The efflux transfer constant calculated for spilanthol was 0.1 min-1. This equals a brain half-time disappearance of 6.4 min. The comparative results of on-going BBB studies, including the permeability properties of pellitorine, will be reported as well. Seen the different possible pharmacological targets of these plant NAAs and their pharmaco-ethnological use, our BBB results may trigger further exploration into the medicinal use of these important plant metabolites.
References
[1] Boonen J, Bronselaer A, Nielandt J, Veryser L, De Tré G, De Spiegeleer B. Alkamid database: Chemistry, occurance and functionality of plant N-alkylamides. J Ethnopharmacol 2012;142(3):563-59
