Blood-brain barrier permeability study of ginger constituents.

Ginger, the rhizome of Zingiber officinale Roscoe is of great importance in the traditional medicine for the treatment of various diseases. More than 400 constituents have been reported in the plant, the most important ones being the gingerol and shogaol derivatives. Positive effects of ginger extracts and isolated [6]-gingerol have been proved in animal models of anxiety, Alzheimer's disease, Parkinson's disease and epilepsy. Taken in consideration these promising positive effects of ginger and its constituents in the central nervous system, the isolation of gingerol and shogaol derivatives ([6]-gingerol (1), [8]-gingerol (2), [10]-gingerol (3), [6]-shogaol (4), [10]-shogaol (5), 1-dehydro-[6]-gingerdione (6), 1-dehydro-[10]-gingerdione (7)) and investigation of their transcellular passive diffusion across the blood-brain barrier (BBB) were carried out. For this purpose, a Parallel Artificial Membrane Permeability Assay for the Blood-Brain Barrier (PAMPA-BBB) was chosen that had previously been validated for natural compounds. Based on our results, [6]-gingerol, [8]-gingerol and [6]-shogaol were found to be able to penetrate the BBB via passive diffusion, suggesting them to contribute to the positive effects of ginger extracts in the central nervous system.