Digenea simplex Domoic acid

Alkaloids derived from glutamic acid, other than y-aminobutyric acid (GABA), include kainic acid isolated from Digenea simplex, domoic acid isolated from Chondria armata, acromelic acids isolated from Clitocybe acromelalga, ibotenic acid isolated from Amanita strobiliformis Amanita pantherina), and tricholomic acid isolated from Tricholoma musucaria, and are described in this chapter. 

The red alga Digenea simplex has been used for the treatment of roundworm disease for centuries. Its active principle is kainic acid. The related domoic acid is a constituent of another red alga, Chondria armata, used for the same purpose. These compounds, known as kainoids, are potent neurotoxins and excitatory amino acids. Kainoids are important tools in neurophysiological research. Domoic acids are also produced by diatoms and were responsible for the shellfish poisonings known as amnesic shellfish poisonings that occurred in Canada in 1987. 

The ability of the alga Digenea simplex to combat intestinal worms has been exploited for many years in Japan.28 The active component has been shown to be (-)-a-kainic acid 2 [NB not (+)-a-allokainic acid 3] and similar properties have been reported for (-)-domoic acid 4.4b Insecticidal and/or anthelmintic properties of the acromelic acids have not been reported to date. 

The isomeric acromelic acids A and B display a powerful neuroexcita-tory action and are structurally related to the anthelmintic kainic acid (406,407) and domoic acid (408), the known principles from the marine red algae Digenea simplex and Chondria armata, respectively. Both of the latter amino acids, the structures of which were determined by chemical and X-ray studies, attracted considerable interest as well because of their... 

Kanoids (kainic and domoic acid) Palmaria palmata, Digenea simplex ... 

Figure 1. HPLC analysis for domoic acid of red algae (1) Chondria armata (994 ppm), (2) Coelothrix irregularis (6 ppm), (3) Digenea simplex (<1 ppm), (4) standard of domoic acid.

Digenea simplex. This seaweed is known to contain a high concentration (1940 ppm) of kainic acid, an anthelminthic and excitatory amino acid related to domoic acid. Samples... 

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