Domoic acid

Domoic acid (DA) is a kainic acid–type neurotoxin that causes amnesic shellfish poisoning (ASP). It is produced by algae and accumulates in shellfish, sardines, and anchovies. When sea lions, otters, cetaceans, humans, and other predators eat contaminated animals, poisoning may result. Exposure to this compound affects the brain, causing seizures, delirium and possibly death.

There has been little use of domoic acid throughout history except for in Japan, where it has been used as an anthelmintic for centuries. Domoic acid was first isolated in 1959 from a species of red algae, Chondria armata, in Japan, which is commonly referred to as dōmoi (ドウモイ) in the Tokunoshima dialect, or hanayanagi. Poisonings in history have been rare, or undocumented; however, it is thought that the increase in human activities is resulting in an increasing frequency of harmful algal blooms along coastlines in recent years. In 2015, the North American Pacific coast was heavily impacted by an algal bloom, consisting predominantly of the domoic acid-producing pennate diatom, Pseudo-nitzschia. Consequently, elevated levels of domoic acid were measured in stranded marine mammals, prompting the closure of beaches and damaging razor clam, rock crab and Dungeness crab fisheries.

In 1961, seabirds attacked the Capitola area in California, and though it was never confirmed, it was later hypothesized that they were under the influence of domoic acid.

In 1987, in Prince Edward Island, Canada, there was a shellfish poisoning resulting in 3 deaths. Blue mussels (Mytilus edulis) contaminated with domoic acid were blamed.

Domoic acid has been suggested to have been involved in an incident which took place on June 22, 2006, when a California brown pelican flew through the windshield of a car on the Pacific Coast Highway.

On Friday, June 14, 2019, a teenager was attacked and injured by a sea lion that was alleged to be under the influence of domoic acid in Pismo Beach on the Central California coast.

Domoic acid is a structural analog of kainic acid, proline, and endogenous excitatory neurotransmitter glutamate. Ohfune and Tomita, who wanted to investigate its absolute stereochemistry, were the first and only to synthesize domoic acid in 1982.

In 1999, using ¹³C- and ¹⁴C-labelled precursors, the biosynthesis of domoic acid in the diatom genus Pseudo-nitzschia was examined. After addition of [1,2-13C2]-acetate, NMR spectroscopy showed enrichment of every carbon in domoic acid, indicating incorporation of the carbon isotopes. This enrichment was consistent with two biosynthetic pathways. The labeling pattern determined that domoic acid can be biosynthesized by an isoprenoid intermediate in combination with a tricarboxylic acid (TCA) cycle intermediate.