Application of radioligand receptor binding assays in the search for CNS active principles from Chinese medicinal plants

Extracts of Schefflera bodinieri and S. delavayi (Araliaceae), Celastrus angulatus and C. orbiculatus (Celastraceae), Clerodendrum mandarinorum and C. bungei (Verbenaceae), Periploca callophylla and P. forrestii (Asclepiadaceae), Alangium platanifolium (Alangiaceae) and Uncaria rhynchophylla (Rubiaceae) were assessed for CNS activity against 18 radioligand receptor binding assays. The receptors used were alpha 1-, alpha 2- and beta-adrenoceptors, 5HT-1, 5HT-1A, 5HT-2, opiate, adenosine-1, benzodiazepine, Ca+2 channel, sulphonylureas, dopamine-1, dopamine-2, muscarinic, histamine-1, Na+/K+ ATPase, GABA(A) and GABA(B). The results indicate that these ligand-receptor binding assays are useful for understanding the mode of action of herbal medicines and for bioassay guided fractionation of plant active ingredients.