THE CONTRIBUTION OF AMERICAN PLANTS TO PHARMACEUTICAL SCIENCES

American flora, mainly that of tropical forests, is still the main sou rce of botanical species and biodiversity in spite of progressive depl etion. Many natural substances used as pharmaceutical tools for the in vestigation of biological mechanisms and for the identification of rec eptors are reported. Some active constituents of American plants have led to the development of new drugs: e.g., the cinchona alkaloids to n ew antimalarial aminoquinolines, the quaternary constituents of curare to a new generation of myorelaxant agents, and podophyllotoxin to new antitumoural drugs.