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Cardenolides

Cardenolide
Cardenolide.png
Identifiers
3D model (Jmol) Interactive image
Interactive image
ChemSpider 19954501 YesY
PubChem 3035019
Properties
C23H34O2
Molar mass 342.51486
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY  (what is YesYN ?)
Infobox references

Cardenolide is a type of steroid. Many plants contain derivatives, collectively known as cardenolides, including many in the form of cardenolide glycosides (cardenolides that contain structural groups derived from sugars). Cardenolide glycosides are often toxic; specifically, they are heart-arresting.

The term derives card- "heart" (from Greek καρδία kardiā) and the suffix -enolide, referring to the lactone ring at C17. It should not 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).

Cardenolides are C(23)-steroids with methyl groups at C-10 and C-13 and a five-membered lactone (specifically a butenolide) 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:

Bufadienolide and Marinobufagenin are similar in structure and function.

Some plant and animal species use cardenolides as defense mechanisms, notably the milkweed butterflies. Species such as the monarch and the queen the cardenolides contained in the milkweeds (Asclepias) that they mostly feed on as larvae. The cardenolide content in butterflies deters most vertebrate predators, except a few which have evolved to become cardenolide-tolerant, such as the 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. In addition to milkweeds and other members of the Apocynaceae, plants in at least 12 botanical families have convergently evolved cardenolides.


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