Apocynaceae: The dogbane family of the order Gentianales. Members of the family have milky, often poisonous juice, smooth-margined leaves, and flowers in clusters. Asclepiadacea (formerly the milkweed family) has been included since 1999 and before 1810.Aspidosperma: A plant genus of the family APOCYNACEAE. It contains ellipticine.Asclepiadaceae: The milkweed plant family of the order Gentianales, subclass Asteridae, class Magnoliopsida. It includes many tropical herbs and shrubby climbers; most with milky juice. Flowers have five united petals. Fruits are podlike, usually with tufted seeds.Tabernaemontana: A plant genus of the family APOCYNACEAE that contains bisindole alkaloids and IBOGAINE.Asclepias: A plant genus of the family ASCLEPIADACEAE. This is the true milkweed; APOCYNUM & EUPHORBIA hirta are rarely called milkweed. Asclepias asthmatica has been changed to TYLOPHORA.Periploca: A plant genus of the family ASCLEPIADACEAE. It is a source of periplocosides (pregnane steroid glycosides).Rauwolfia: A plant genus of the APOCYNACEAE or dogbane family. Alkaloids from plants in this genus have been used as tranquilizers and antihypertensive agents. RESERPINE is derived from R. serpentina.Plant Extracts: Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.