(2S,5S)-9-[(S)-1-エテニル-1,5-ジメチル-4-ヘキセニル]-1,2,4,5,6,8-ヘキサヒドロ-5-(ヒドロキシメチル)-1-メチル-2-(1-メチルエチル)-3H-ピロロ[4,3,2-gh]-1,4-ベンゾジアゾニン-3-オン

Lyngbyatoxin A is known as the causative agent of 'swimmer’s itch' with its highly inflammatory effect (A15358). Lyngbyatoxin A is a potent irritant and vesicant, as well as a carcinogen. Low concentrations more commonly encountered cause milder symptoms, known as seaweed dermatitis. (Wikipedia)

Lyngbyatoxin A is a tumor promoter. Lyngbyatoxin A and related compounds bind to the cysteine-rich C1 domains (C1A and C1B) of protein kinase C (PKC) isozymes to activate them, possibly leading to tumor formation (A15358). In cancer cells, PKC isozymes are involved in cell proliferation, survival, invasion, migration, apoptosis, angiogenesis, and anticancer drug resistance through their increased or decreased participation in various cellular signaling pathways (L2138). Lyngbyatoxin A also induces ornithine decarboxylase (A3219). The ornithine decarboxylation reaction catalyzed by ornithine decarboxylase (ODC) is the first and committed step in the synthesis of polyamines, particularly putrescine, spermidine and spermine. ODC is upregulated in a wide variety of cancers. The mechanism by which ODC promotes carcinogenesis is complex and not entirely known. Along with their direct effect on DNA stability, polyamines also upregulate gap junction genes and downregulate tight junction genes. Gap junction genes are involved in communication between carcinogenic cells and tight junction genes act as tumor suppressors. (Wikipedia)

Lyngbyatoxin A is a cyanotoxin produced by certain cyanobacteria species, notably <i>Moorea producens</i> (formerly classified as <i>Lyngbya majuscula</i>). It is used as a defensive secretion to protect this cyanobacteria from predation by fish, being a potent irritant and vesicant, as well as a carcinogen. The toxin is highly inflammatory and vesicatory.