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Cardenolide



Cardenolides are a type of steroids. Many plants contain cardenolides in the form of cardenolide glycosides (i.e. cardenolides that contain structural groups derived from sugars; see Glycoside). Cardenolides are toxic (specifically, heart-arresting).

Contents

Etymology

Supposedly, the term derives from Greek kardiā, heart. It shouldn't be confused with cardanolides. Cardanolides are a class of steroids (or aglycones if viewed as cardiac glycoside constituents), and cardenolides are a subtype of this class (see MeSH D codes list).

Structure

  Cardenolides are C(23)-steroids with methyl groups at C-10 and C-13 and a five-membered lactone at C-17. They are aglycone constituents of cardiac glycosides and must have at least one double bond in the molecule. The class includes cardadienolides and cardatrienolides. Members include:

As defense mechanism

Some plant and animal species use cardenolides as a defense mechanism, most notably the monarch butterflies. Adult monarch butterflies store the cardenolides they have built-up as larvae feeding mostly on milkweeds (Asclepias). The cardenolide content in butterflies deters vertebrate predators, with some exceptions of cardenolide-tolerant predators like black-backed orioles (Icterus abeillei Lesson) and black headed grosbeaks (Pheucticus melanocephalus Swainson) that account for 60% of monarch butterfly mortalities in the overwintering sites in central Mexico.

See also

Bufadienolide

Cardiac glycoside

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Cardenolide". A list of authors is available in Wikipedia.
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