Alkaloid, << AL kuh loyd, >> is any of a group of organic bases found in plants. Alkaloids contain carbon, hydrogen, nitrogen, and oxygen. Small amounts of many alkaloids can have a powerful effect on people and animals, and are used as medicines or poisons. Some useful alkaloids are synthesized (artificially put together) in chemical factories, as well as taken from plants.
Alkaloids with medicinal value include codeine and morphine from the poppy plant, and quinine and quinidine from the cinchona. Others are caffeine from coffee and tea, cocaine from coca, ephedrine from the Ephedra genus of plants, reserpine from Rauwolfia serpentina, and tubocurarine from curare.
Poisonous alkaloids from such plants as curare are used on arrowheads by peoples who hunt chiefly with bow and arrow. The hemlock plant, which was used to kill the Greek philosopher Socrates, contains lethal amounts of conine and other alkaloids. Aconitine from the aconite plant is also highly poisonous. Nicotine, an alkaloid of the tobacco plant, is toxic to human beings and is also used to kill insects.
