Cantharidin
Encyclopedia
Cantharidin, a type of terpenoid
, is a poison
ous 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.
Cantharidin was first isolated in 1810 by Pierre Robiquet, a French chemist then living in Paris, from Lytta vesicatoria. Robiquet demonstrated that cantharidin was the actual principle responsible for the aggressively blistering properties of the coating of the eggs of that insect, and established that cantharidin had very definite toxic and poisonous properties comparable in degree to that of the most violent poisons known in the 19th century, such as strychnine
. It is an odorless and colorless solid at room temperature
. It is secreted by the male blister beetle
and given to the female during 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.
medication to remove wart
s and tattoo
s and to treat the small papules of Molluscum contagiosum
.
When ingested
by humans, the is around 0.5 mg/kg, with a dose of as little as 10 milligrams being potentially fatal. Ingesting cantharidin can initially cause severe damage to the lining of the gastrointestinal and urinary tract, and may also cause permanent renal damage. Symptoms of cantharidin poisoning include haematuria, abdominal pains, and rarely priapism
.
The level of cantharidin in blister beetles can be quite variable: Among blister beetles of the genus Epicauta in Colorado
, E. pennsylvanica contain approximately 0.2 mg, E. maculata contain 0.7 mg, and E. immaculata contain 4.8 mg per beetle; males also contain higher levels than females.
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.
Topical treatment with cantharidin appears to have some effect in an animal model of cutaneous leishmaniasis
.
Terpenoid
The terpenoids , sometimes called isoprenoids, are a large and diverse class of naturally occurring organic chemicals similar to terpenes, derived from five-carbon isoprene units assembled and modified in thousands of ways. Most are multicyclic structures that differ from one another not only in...
, is a poison
Poison
In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....
ous chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
secreted by many species of blister beetle
Blister beetle
Blister beetles are beetles of the family Meloidae, so called for their defensive secretion of a blistering agent, cantharidin. There are approximately 7,500 known species worldwide. Many are conspicuous and some aposematically colored, announcing their toxicity to would-be...
, and most notably by the Spanish fly
Spanish fly
The Spanish fly is an emerald-green beetle in the family Meloidae, Lytta vesicatoria. Other species of blister beetle used by apothecaries are often called by the same name...
, Lytta vesicatoria. The false blister beetles
Oedemeridae
The family Oedemeridae is a cosmopolitan group of beetles commonly known as false blister beetles, though some recent authors have coined the name pollen-feeding beetles...
and cardinal beetles also have cantharidin.
History
Strychnine
Strychnine is a highly toxic , colorless crystalline alkaloid used as a pesticide, particularly for killing small vertebrates such as birds and rodents. Strychnine causes muscular convulsions and eventually death through asphyxia or sheer exhaustion...
. It is an odorless and colorless solid at room temperature
Room temperature
-Comfort levels:The American Society of Heating, Refrigerating and Air-Conditioning Engineers has listings for suggested temperatures and air flow rates in different types of buildings and different environmental circumstances. For example, a single office in a building has an occupancy ratio per...
. It is secreted by the male blister beetle
Blister beetle
Blister beetles are beetles of the family Meloidae, so called for their defensive secretion of a blistering agent, cantharidin. There are approximately 7,500 known species worldwide. Many are conspicuous and some aposematically colored, announcing their toxicity to would-be...
and given to the female during mating. Afterwards the female beetle will cover its eggs with it as a defense against predators. The complete mechanism of the biosynthesis
Biosynthesis
Biosynthesis is an enzyme-catalyzed process in cells of living organisms by which substrates are converted to more complex products. The biosynthesis process often consists of several enzymatic steps in which the product of one step is used as substrate in the following step...
is currently unknown.
Medical uses
Diluted solutions of cantharidin can be used as a topicalTopical
In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, anus, throat, eyes and ears.Many topical medications are epicutaneous, meaning that they are applied directly to the skin...
medication to remove wart
Wart
A wart is generally a small, rough growth, typically on a human’s hands or feet but often other locations, that can resemble a cauliflower or a solid blister. They are caused by a viral infection, specifically by human papillomavirus 2 and 7. There are as many as 10 varieties of warts, the most...
s and tattoo
Tattoo
A tattoo is made by inserting indelible ink into the dermis layer of the skin to change the pigment. Tattoos on humans are a type of body modification, and tattoos on other animals are most commonly used for identification purposes...
s and to treat the small papules of Molluscum contagiosum
Molluscum contagiosum
Molluscum contagiosum is a viral infection of the skin or occasionally of the mucous membranes. It is caused by a DNA poxvirus called the molluscum contagiosum virus . MCV has no animal reservoir, infecting only humans. There are four types of MCV, MCV-1 to -4; MCV-1 is the most prevalent and...
.
Medical risks for humans
Its potential for adverse effects has led it to being included in a list of "problem drugs" used by dermatologists and emergency personnel.When ingested
Ingestion
Ingestion is the consumption of a substance by an organism. In animals, it normally is accomplished by taking in the substance through the mouth into the gastrointestinal tract, such as through eating or drinking...
by humans, the is around 0.5 mg/kg, with a dose of as little as 10 milligrams being potentially fatal. Ingesting cantharidin can initially cause severe damage to the lining of the gastrointestinal and urinary tract, and may also cause permanent renal damage. Symptoms of cantharidin poisoning include haematuria, abdominal pains, and rarely priapism
Priapism
Priapism is a potentially harmful and painful medical condition in which the erect penis or clitoris does not return to its flaccid state, despite the absence of both physical and psychological stimulation, within four hours. There are two types of priapism: low-flow and high-flow. Low-flow...
.
The level of cantharidin in blister beetles can be quite variable: Among blister beetles of the genus Epicauta in Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, E. pennsylvanica contain approximately 0.2 mg, E. maculata contain 0.7 mg, and E. immaculata contain 4.8 mg per beetle; males also contain higher levels than females.
The extreme toxicity of cantharidin makes any use as an aphrodisiac
Aphrodisiac
An aphrodisiac is a substance that increases sexual desire. The name comes from Aphrodite, the Greek goddess of sexuality and love. Throughout history, many foods, drinks, and behaviors have had a reputation for making sex more attainable and/or pleasurable...
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.Research
Laboratory studies with cultured tumor cell lines suggest that cantharidin analogs might have anti-cancer activity through the inhibition of protein phosphatase 2A.Topical treatment with cantharidin appears to have some effect in an animal model of cutaneous leishmaniasis
Cutaneous leishmaniasis
Cutaneous leishmaniasis is the most common form of leishmaniasis. It is a skin infection caused by a single-celled parasite that is transmitted by sandfly bites...
.