alkaloid

[ al-kuh-loid ]

/ ˈæl kəˌlɔɪd /

Biochemistry, Chemistry, Pharmacology

noun

any of a large class of organic, nitrogen-containing ring compounds of vegetable origin and sometimes synthesized, some of which are liquid but most of which are solid, that have a bitter taste, that are usually water-insoluble and alcohol-soluble, that combine with acids without the loss of a water molecule to form water-soluble hydrochlorides, hydrobromides, or the like, and that usually exhibit pharmacological action, as nicotine, morphine, or quinine.

adjective

resembling an alkali; alkaline.

Nearby words

alkaline-earth metal, alkaline-earth metals, alkalinity, alkalinuria, alkalize, alkaloid, alkaloidal, alkalosis, alkaluria, alkane, alkane series

Origin of alkaloid

First recorded in 1825–35; alkal(i) + -oid

Related forms

non·al·ka·loid, noun, adjective

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for alkaloid

This consists in the use of emetics or the stomach-pump, with lime-water, which decomposes the alkaloid.
Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 5|Various
One part of the alkaloid is dissolved in 36·6 of benzene, and in 76 parts of amyl alcohol.
Poisons: Their Effects and Detection|Alexander Wynter Blyth
Its active principle is theobromine, an alkaloid greatly resembling caffeine, the active principle of coffee and tea.
Cooley's Cyclopdia of Practical Receipts and Collateral Information in the Arts, Manufactures, Professions, and Trades..., Sixth Edition, Volume I|Arnold Cooley
The alkaloid atropine has been quite thoroughly studied with results of great interest.
Scientific American Supplement, No. 415, December 15, 1883|Various

On the other hand, the alkaloid can be transported and kept without decomposition.
Scientific American Supplement, No. 623, December 10, 1887|Various

British Dictionary definitions for alkaloid

alkaloid

/ (ˈælkəˌlɔɪd) /

noun

any of a group of nitrogenous basic compounds found in plants, typically insoluble in water and physiologically active. Common examples are morphine, strychnine, quinine, nicotine, and caffeine

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for alkaloid

alkaloid

[ ăl′kə-loid′ ]

n.

Any of various organic compounds, such as nicotine and morphine, that have basic chemical properties and that usually contain at least one nitrogen atom in a heterocyclic ring.

Science definitions for alkaloid

alkaloid

[ ăl′kə-loid′ ]

Any of a large class of naturally occurring, complex organic compounds that contain nitrogen and have physiological effects on animals, including humans. Most alkaloids occur in plants, although some are produced by fungi and animals. Alkaloids are bases and usually form colorless crystalline solids with a bitter taste. They have a wide range of effects and are used as medicines and poisons. Morphine, quinine, strychnine, codeine, caffeine, cocaine, and nicotine are all alkaloids.