alkaloid

al·ka·loid

noun \ˈal-kə-ˌlȯid\

Definition of ALKALOID

: any of numerous usually colorless, complex, and bitter organic bases (as morphine or caffeine) containing nitrogen and usually oxygen that occur especially in seed plants and are typically physiologically active

— al·ka·loi·dal \ˌal-kə-ˈlȯi-d^əl\ adjective

First Known Use of ALKALOID

circa 1831

Rhymes with ALKALOID

adenoid, amoeboid, aneroid, anthropoid, arachnoid, asteroid, Australoid, carcinoid, Caucasoid, celluloid, crystalloid, echinoid, ellipsoid, embryoid, eunuchoid, flavonoid, helicoid, hemorrhoid, hominoid, humanoid, hysteroid, metalloid, Mongoloid, myeloid, nautiloid, nucleoid, null and void, obovoid, opioid, osteoid, overjoyed, paranoid, planetoid, Polaroid, retinoid, rheumatoid, solenoid, Stalinoid, trapezoid, unalloyed, unemployed

al·ka·loid

noun \ˈal-kə-ˌlȯid\   (Medical Dictionary)

Medical Definition of ALKALOID

: any of numerous usually colorless, complex, and bitter organic bases (as morphine or caffeine) containing nitrogen and usually oxygen that occur especially in seed plants and are typically physiologically active

—al·ka·loi·dal \ˌal-kə-ˈlȯid-^əl\ (audio pronunciation) adjective

alkaloid

noun    (Concise Encyclopedia)

Basic (see base) organic compounds of plant origin, containing combined nitrogen. Alkaloids are amines, so their names usually end in “ine” (e.g., caffeine, nicotine, morphine, quinine). Most have complex chemical structures of multiple ring systems. They have diverse, important physiological effects on humans and other animals, but their functions in the plants that produce them are poorly understood. Some plants (e.g., opium poppy, ergot fungus) produce many different alkaloids, but most produce only one or a few. Certain plant families, including the poppy family (Papaveraceae) and the nightshade family (Solanaceae), are particularly rich in them. Alkaloids are extracted by dissolving the plant in dilute acid.