alkaloid

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alkaloid

 [al´kah-loid]
one of a large group of organic, basic substances found in plants. They are usually bitter in taste and are characterized by powerful physiologic activity. Examples are morphine, cocaine, atropine, quinine, nicotine, and caffeine. The term is also applied to synthetic substances that have structures similar to plant alkaloids, such as procaine.
vinca a's see vinca alkaloids.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

al·ka·loid

(al'kă-loyd),
Originally, any one of hundreds of plant and fungal products distinguished by alkaline (basic) reactions, but now restricted to heterocyclic nitrogenous and often complex structures possessing pharmacologic activity; their trivial names usually end in -ine (for example, morphine, atropine, colchicine). Alkaloids are synthesized by plants and are found in the leaf, bark, seed, or other parts, usually constituting the active principle of the crude drug; they are a loosely defined group, but may be classified according to the chemical structure of their main nucleus. For medicinal purposes, due to improved water solubility, the salts of alkaloids (for example, morphine sulfate, codeine phosphate) are usually used. see also individual alkaloid or alkaloid class.
Synonym(s): vegetable base
Farlex Partner Medical Dictionary © Farlex 2012

alkaloid

(ăl′kə-loid′)
n.
Any of various organic compounds that are usually basic and contain at least one nitrogen atom in a heterocyclic ring, occurring chiefly in flowering plants. Many alkaloids, such as nicotine, quinine, cocaine, and morphine, are known for their poisonous or medicinal attributes.

al′ka·loi′dal (-loid′l) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

alkaloid

Herbal medicine
Any of a number of medicinally active compounds produced by plants; alkaloids are often active in small amounts and toxic in large amounts; well-known alkaloids produced by plants include caffeine, codeine, morphine, nicotine, quinine and strychnine.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

al·ka·loid

(al'kă-loyd)
Originally, any one of hundreds of plant products distinguished by alkaline (basic) reactions, but now restricted to heterocyclic nitrogen-containing and often complex structures possessing pharmacologic activity; their trivial names usually end in -ine (e.g., morphine, atropine, colchicine). Alkaloids are synthesized by plants and are found in the leaf, bark, seed, or other parts, usually constituting the active principle of the crude drug; they are a loosely defined group but may be classified according to the chemical structure of their main nucleus. For medicinal purposes, due to improved water solubility, the salts of alkaloids are typically used.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

Alkaloid

A type of chemical commonly found in plants and often having medicinal properties.
Mentioned in: Chemotherapy
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.

al·ka·loid

(al'kă-loyd)
Heterocyclic nitrogenous and often complex structures possessing pharmacologic activity; synthesized by plants and are found in the leaf, bark, seed, or other parts, usually constituting the active principle of the crude drug; they comprise a loosely defined group.
Medical Dictionary for the Dental Professions © Farlex 2012