Alkaloids are a class of basic, nitrogen containing compounds of organic origin, for example nicotine. Most are very complex molecules and many have significant pharmacological properties.

Alkaloids are lavishly produced by Poison Dart Frogs, found in central and south american rainforests. Such frogs are small but intensely coloured as a warning to predators, and the warning should be heeded. The frogs secrete toxic alkaloid compounds from glands in their skin that can kill quite large animals (although each frog produces only microgram quantities), and indeed are used by indigenous peoples to tip hunting arrows and darts. Some 200 of these alkaloids have been studied in the United States by NMR and mass spectroscopy. It has been determined that the toxins work by interefering with ion transfer across cell membranes. Several are currently in use in neuroscientific research. One frog alkaloid isolated in 1992 has shown analgesic properties far greater than those of morphine, and is being studied as a possible base for the design of a new family of painkillers.

Any of a class of over 3000 known nitrogen-containing compounds (such as morphine, caffeine, cocaine and nicotine) that are typically basic (pH over 7) and are produced by plants but have strong physiological effects on animals (including humans). They are synthesized from amino acid precursors such as tryptophan and tyrosine.

From the BioTech Dictionary at For further information see the BioTech homenode.

Al"ka*loid (#), Al`ka*loid"al (#), a. [Alkali + -oid: cf. F. alcaloide.]

Pertaining to, resembling, or containing, alkali.


© Webster 1913.

Al"ka*loid (#), n. Chem.

An organic base, especially one of a class of substances occurring ready formed in the tissues of plants and the bodies of animals.

Alcaloids all contain nitrogen, carbon, and hydrogen, and many of them also contain oxygen. They include many of the active principles in plants; thus, morphine and narcotine are alkaloids found in opium.


© Webster 1913.

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