EUROPEAN HERBS WITH CHOLINERGIC ACTIVITIES - POTENTIAL IN DEMENTIA THERAPY

We investigated plants reputed in herbal encyclopedias to enhance memo ry or alleviate mental disorder for cholinergic activities since this transmitter system has been implicated in memory and dementia. Crude e xtracts were applied to human brain homogenates to determine whether a ny inhibit acetylcholinesterase. Of three plants with reputed memory e nhancing properties (rosemary, sage and balm), extracts of sage (Salvi a officinalis) inhibited the brain enzyme in a concentration dependant manner. 50% enzyme inhibition was obtained at a concentration of 0.07 mu g essential oil per ml and 1.5 mg fresh herb per ml. None of the k nown and commercially available chemical constituents of sage oil so f ar tested (borneol, caffeic acid, camphor, cineol or thujone) inhibite d the enzyme, indicating that the active plant constituent(s) may be a n as yet unidentified compound(s). In parallel studies, plants with in secticide or vermifuge (antihelminthic) properties, which frequently d epend on cholinergic activities, were examined for cholinergic recepto r interactions. Crude alcoholic extracts of wormwood, balm and angelic a displaced nicotine binding to the nicotinic receptor in a concentrat ion dependant manner, with IC50 values ranging from 3-15 mg/ml. Compon ents of these plants may be relevant in relation to dementia therapy s ince there is a loss of nicotinic receptors in Alzheimer's disease and related disorders and stimulation of the nicotinic receptor leads to increased receptor numbers.