Conessine is an alkaloid obtained from the bark and seeds of Holarrhena antidysenterica
trees. It binds with high affinity to rat and human histamine H3
receptors in radio-ligand binding assays, acting as a receptor antagonist [2-3
antagonists are being researched as potential drugs for the treatment of neurodegenerative conditions and for their stimulant and nootropic effects. For example, pitolisant
is in clinical trial for Parkinson's disease, narcolepsy, cataplexy and excessive daytime sleepiness.