ABSTRACT
Natural products have long been major sources of pharmaceutical products in medicine. We have undertaken a series of studies designed to characterize the pharmacologic profiles of natural products used to treat psychotic illnesses in Korean traditional medicine. In our previous screening assays, we found that three of plant extracts (Coptidis j, Citrus u, and Phellodendron a) contain active components which show relatively potent binding to alpha-2 adrenoceptors. The present study is to explore pharmacologic activities of extracts as agonism or antagonism by G-protein modulations in radioligand receptor binding study. We have found that two extracts(Coptidis j and Phellodendron a) contain active ingredients which have antagonistic properties to alpha-2 adrenoceptors, whereas one plant extract (Citrus u) has agonistic properties. The demonstration of three plant extracts used to treat psychotic illnesses in Korea may help in the elucidation or their pharmacologic characteristics and provide insights for the development of new psychotropic drugs.