cantharidin

Cantharidin
IUPAC name	2,6-Dimethyl-4,10-dioxatricyclo- [5.2.1.02,6]decane-3,5-dione
Other names	Cantharidin
Identifiers
CAS number	56-25-7
SMILES	O=C2OC([C@@]1(C)[C@@H] 3CC[C@@H](O3)[C@]12C)=O
Properties
Molecular formula	C10H12O4
Molar mass	196.20 g/mol
Density	1.41 g/cm³
Melting point	212 °C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Cantharidin, a type of terpenoid, is a poisonous chemical compound secreted by many species of blister beetle, and most notably by the Spanish fly, Lytta vesicatoria. The false blister beetles and cardinal beetles also have cantharidin.

History

Black Blister Beetle Epicauta pennsylvanica

Cantharidin was first isolated by Pierre Robiquet in 1810. It is an odorless and colorless solid at room temperature. It is secreted by the male blister beetle and given to the female during the mating. Afterwards the female beetle will cover its eggs with it as a defense against predators. The complete mechanism of the biosynthesis is currently unknown. If cantharidin is ingested, it severely irritates the urinary tract as it is excreted, causing swelling of the genitalia. This can cause a harmful condition known as priapism in men, where an erection lasts more than about four hours.

Medical uses

Diluted, it can be used to remove warts^[1] and tattoos and to treat the small papules of Molluscum contagiosum.^[2]

Medical risks for humans

Its potential for adverse effects has led it to being included in a list of "problem drugs" used by dermatologists.^[3]

When ingested by humans, the LD₅₀ is around 0.5 mg/kg, with a dose of as little as 10 milligrams being potentially fatal. Ingesting cantharidin can also cause permanent renal damage. Symptoms of cantharidin poisoning include haematuria and abdominal pains.

The extreme toxicity of cantharidin makes any use as an aphrodisiac highly dangerous because it can easily cause death. As a result, it is illegal to sell (or use) cantharidin for this purpose in many countries.

Medical risks for animals

Horses are highly sensitive to cantharidin: the LD₅₀ for horses is approximately 1 mg/kg of the horse's body weight. Horses may be accidentally poisoned when fed bales of fodder with blister beetles in them.[1]

Footnotes

External links

• Cantharidin
• Molecule of the Month