Brevetoxin
Encyclopedia
Brevetoxin or brevetoxins, are a suite of cyclic polyether compounds produced naturally by a species of dinoflagellate
known as Karenia brevis
. Brevetoxins are neurotoxins that bind to voltage-gated sodium channels in nerve cells, leading to disruption of normal neurological processes and causing the illness clinically described as neurotoxic shellfish poisoning
(NSP).
Although brevetoxins are most well-studied in K. brevis, they are also found in other species of Karenia
and at least one large fish kill
has been traced to brevetoxins in Chattonella.
Other Brevetoxins:
Brevetoxin-B was synthesized in 1995 by K. C. Nicolaou and coworkers in 123 steps with 91% average yield (final yield ~9·10−6). and in 2004 a total of 90 steps with an average 93% yield for each step (0.14% overall).
K. C. Nicolaou and coworkers reported their synthesis of Brevetoxin-1 in 1998. In 2009, Michael Crimmins and co-workers reported their synthesis of Brevetoxin-1 as well.
formation involving Claisen condensation
of a dicarboxylic acid with the alpha-position of the second carboxylic function with a loss of a carboxyl group.
Dinoflagellate
The dinoflagellates are a large group of flagellate protists. Most are marine plankton, but they are common in fresh water habitats as well. Their populations are distributed depending on temperature, salinity, or depth...
known as Karenia brevis
Karenia brevis
Karenia brevis is a marine dinoflagellate common in Gulf of Mexico waters, and is the organism responsible for Florida red tide, as well as red tide in Texas.-Description:K...
. Brevetoxins are neurotoxins that bind to voltage-gated sodium channels in nerve cells, leading to disruption of normal neurological processes and causing the illness clinically described as neurotoxic shellfish poisoning
Neurotoxic shellfish poisoning
Neurotoxic Shellfish Poisoning is caused by the consumption of shellfish contaminated by breve-toxins or brevetoxin analogs.Symptoms in humans include vomiting and nausea and a variety of neurological symptoms such as slurred speech...
(NSP).
Although brevetoxins are most well-studied in K. brevis, they are also found in other species of Karenia
Karenia (dinoflagellate)
Karenia is a genus of 12 species of dinoflagellates which were formerly included in the genus Gymnodinium.A number of species cause red tides, including Karenia brevis off the coast of Florida and Karenia mikimotoi which was first described in Japan, but is now found in the Atlantic ocean as well,...
and at least one large fish kill
Fish kill
The term fish kill, known also as fish die-off and as fish mortality, is a localized die-off of fish populations which may also be associated with more generalised mortality of aquatic life...
has been traced to brevetoxins in Chattonella.
| Brevetoxin A | Brevetoxin B | |
|---|---|---|
| chemical structure |  |
 |
| subtypes |
|
|
Other Brevetoxins:
- Brevetoxin-5 (PbTx-5): like PbTx-3, but acetylatedAcetylationAcetylation describes a reaction that introduces an acetyl functional group into a chemical compound...
hydroxylHydroxylA hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...
group in position 38. - Brevetoxin-6 (PbTx-6): like PbTx-2, but double bond 27-28 is epoxidatedEpoxideAn epoxide is a cyclic ether with three ring atoms. This ring approximately defines an equilateral triangle, which makes it highly strained. The strained ring makes epoxides more reactive than other ethers. Simple epoxides are named from the parent compound ethylene oxide or oxirane, such as in...
.
Brevetoxin-B was synthesized in 1995 by K. C. Nicolaou and coworkers in 123 steps with 91% average yield (final yield ~9·10−6). and in 2004 a total of 90 steps with an average 93% yield for each step (0.14% overall).
K. C. Nicolaou and coworkers reported their synthesis of Brevetoxin-1 in 1998. In 2009, Michael Crimmins and co-workers reported their synthesis of Brevetoxin-1 as well.
Biosynthesis
A proposed biosynthetic route includes a novel polyketidePolyketide
Polyketides are secondary metabolites from bacteria, fungi, plants, and animals. Polyketides are usually biosynthesized through the decarboxylative condensation of malonyl-CoA derived extender units in a similar process to fatty acid synthesis...
formation involving Claisen condensation
Claisen condensation
The Claisen condensation is a carbon–carbon bond forming reaction that occurs between two esters or one ester and another carbonyl compound in the presence of a strong base, resulting in a β-keto ester or a β-diketone...
of a dicarboxylic acid with the alpha-position of the second carboxylic function with a loss of a carboxyl group.
See also
- Red tideRed tideRed tide is a common name for a phenomenon also known as an algal bloom , an event in which estuarine, marine, or fresh water algae accumulate rapidly in the water column and results in discoloration of the surface water. It is usually found in coastal areas...
- Algal bloomAlgal bloomAn algal bloom is a rapid increase or accumulation in the population of algae in an aquatic system. Algal blooms may occur in freshwater as well as marine environments. Typically, only one or a small number of phytoplankton species are involved, and some blooms may be recognized by discoloration...
- Karenia brevisKarenia brevisKarenia brevis is a marine dinoflagellate common in Gulf of Mexico waters, and is the organism responsible for Florida red tide, as well as red tide in Texas.-Description:K...