[General description] [Representative Structure] [Distribution] [Biological activity] [Poisons]]
Sesquiterpene lactones (SQL) are a class of naturally occurring plant terpenoids that are formed from "head-total condensation of three isoprene units and subsequent cyclization and oxidative transformation to produce a cis or trans-fused lactone. Sesquiterpene lactones are characteristic constituents of Compositae. These secondary compounds are primarily classified on the basis of their carbocyclic skeletons into germanocranolides, guaianalides, eudedesmalides, pseudogua! inolides and xanthonolides. The suffix "olide" refers to the lactone function and is based on costunolide, a germanacranoride which is related to the ten-membered carbocyclic sesquiterpene, germacrone.
An individual plant species generally produces one skeletal type of SQL concentrated primarily in the leaves and flower heads. The percentage of SQL per dry weight may vary from 0.01% to 8%. Losses of livestock intoxicated by plants containing SQL are well known. In fact, they have been shown to exhibit a wide range of biological activities.
[General description] [Representative
Structure] [Distribution] [Biological
activity] [Poisons]
Photo from Sesquiterpene Lactones. Chemistry, NMR and Plant Distribution, University of Tokyo Press.
[General description] [Representative
Structure] [Distribution] [Biological
activity] [Poisons]
|
(No. of genera) |
sesquiterpene lactones |
|
| Eupatorieae (50) |
4 | Germacranolides Elemanolides Guaianolides Ambrosanolides Seco-Ambrosanolides |
| Vernonieae (50) |
|
Germacranolides Elemanolides Guaianolides |
| Astereae (100) |
|
Germacranolides Guaianolides Elemanolides |
| Inuleae (100) |
|
Guaianolides Xanthanolides Ambrosanolides Helenanolides Seco-Eudesmanolides Seco-Ambrosanolides Germacranolides |
| Heliantheae (250) |
|
Elemanolides Guaianolides Eudesmanolides Xanthanolides Ambrosanolides Helenanolides Seco-Eudesmanolides Seco-Ambrosanolides Seco-Helenanolides |
| Senecioneae (50) |
|
Germacranolides Xanthanolides Eremophilanolides Helenanolides Bakkenolides |
| Anthemideae (50) |
|
Germacranolides Elemanolides Guaianolides Helenanolides Cadinanolides Chrymoranolides |
| Arcototeae-Calenduleae (50) |
|
Guaianolides |
| Cynareae (50) |
|
Germacranolides Elemanolides Guaianolides Eudesmanolides |
| Mutisieae (55) |
|
Eudesmanolides |
| Lactuceae (75) |
|
Germanocranolides Eudesmanolides Guaianolides |
[General description] [Representative Structure] [Distribution] [Biological activity] [Poisons]
Since many sesquiterpene lactones are also antimicrobial agents, it is possible that they also exert their action by altering the microbial composition of rumen and thus affecting its vital metabolic function. Hence, rumen dysfunction may contribute to the toxicity caused by sesquiterpene lactones in livestock. They are also neurotoxic; a SQL, repin, has been implicated in causing a syndrome similar to Parkinson's disease in horses.
Livestock poisoning from foraging on bitter tasting plants of the family of Compositae is well documented. Besides its deleterious effects on domestic animals, it is well reported that many Compositae plants containing sesquiterpene lactones are also toxic to wild animals.
The toxicity of sesquiterpene lactones is due to binding of the exocyclic methylene group with tissue constituents, such as sulphydril groups and other nucleophilic components.
[General description] [Representative
Structure] [Distribution] [Biological
activity] [Poisons]
| Baccharis cardifolia Tanacetum vulgare |
Baccharis oil | Sheep, Cattle |
| Eupatorium urticifolium | Cattle, Sheep, Goats | |
| Geigeria sp. | Geigerin, Vermeerin | Sheep |
| Asteracae growing
in wild state | Herbivorous, animals in wild state | |
| Hymenoxys odorata | HymenolideHymenoxin Odoratin Paucin Vermeerin Hymenovin | Sheep, Cattle |
| Hymenoxys richardsoni | Vermeerin Psilotropin | Sheep, Cattle |
| Helenium autumnale | Helenalin Mexicanin-E Bigelovin Tenulin Isotenulin | Sheep, Cattle |
| Centaurea solstitialis | Cynaropicrin | Horse |
| Lactuca virosa | Lactucin | Cattle |
[General description] [Representative Structure] [Distribution] [Biological activity] [Poisons]
This series of web pages was created by Stefania Carpino, an undergraduate student at Cornell University for the AS625 class. All comments and suggestions are welcome.
WARNING: These web pages are only meant to be informative. Neither Cornell University nor the author of this site endorse or recommend the use of these plants.