Crown-of-Thorns (Euphorbia milii)
| Description | Distribution | Conditions of poisoning | Control | Toxic principle | Clinical signs | References
A low-growing evergreen shrub with very thorny grooved stems and branches. The stems are purplish brown and are 1-2 feet tall on average, but can reach 3 feet in a warm climate. The thorns are sharp pointed and are 1/2 inch long on avarage. The ovate leaves are 1-3 inches long, few in number, and are found mostly at the growing ends. The cyathia, a type of inflorescence characteristic of the genus Euphorbia, are born in small umbels and have showy, ovate and bright red bracts. The small flowers are produced in clusters of 2-8 at the tips of green flower stem about 1 inch long. Genus Euphorbia includes other commonly available plants such as poinsettia (E. pulcherrima) and snow-on-the-mountain (E. marginata).
The poisonous principle is present in all parts of the plant. Euphorbia species generally are highly unpalatable, but animals may eat them due to lack of good forage. Drying does not destroy the toxicity of the plant, and Euphorbia in hay may be slightly more palatable to livestock. Contact with the white, milky sap may cause severe blistering as well as intense pain to open cuts or eyes. Honey made from the flowers of these plants may be toxic.
The poisonous principles have been identified as phorbol esters. Phorbol esters activate protein kinase C. Protein phosphorylation is increased by protein kinase C which may alter multiple enzyme and other protein functions. Effects may result in cytoskeletal damage and tumor promotion.
genus Euphorbia in Wikipedia
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