A quarter century of pharmacognostic research on Panamanian flora: a review.

Panama is a unique terrestrial bridge of extreme biological importance. It is one of the "hot spots" and occupies the fourth place among the 25 most plant-rich countries in the world, with 13.4 % endemic species. Panamanian plants have been screened for a wide range of biological activities: as cytotoxic, brine shrimp-toxic, antiplasmodial, antimicrobial, antiviral, antioxidant, immunosuppressive, and antihypertensive agents. This review concentrates on ethnopharmacological uses of medicinal plants employed by three Amerindian groups of Panama and on selected plants with novel structures and/or interesting bioactive compounds. During the last quarter century, a total of approximately 390 compounds from 86 plants have been isolated, of which 160 are new to the literature. Most of the work reported here has been the result of many international collaborative efforts with scientists worldwide. From the results presented, it is immediately obvious that the Panamanian flora is still an untapped source of new bioactive compounds.