Table 1.

Main toxins from cyanobacteria, including genera of main producers and action mechanism.

Cyanotoxins	Genera of main producers	Chemical classification	Action mechanism	References
Hepatotoxins
Microcystins	Anabaena, Planktothrix, Nostoc, Anabaenopsis	Cyclic Heptapeptides	Inhibition of protein phosphatases type 1 and 2A	[16,17]
Nodularins	Nodularia	Cyclic Pentapeptídes	Inhibition of protein phosphatases type 1 and 2A	[16,17]
Cylindrospermopsins	Cylindrospermopsis raciborskii, Aphanizomenon ovalisporum, Aphanizomenon zflos-aquae	Guanidine alkaloids	Glutathione and protein synthesis as well as cytochrome P450.	[4]
Neurotoxins
Anatoxin-a	Anabaena, Aphanizomenon, Planktothrix	Alkaloid	Irreversible link to the nicotinic receiver S of acetylcholine	[10,18,19]
Anatoxin-a(s)	Anabaena	Organophosphate	Irreversible inhibitor of acetylcholinesterase	[19,20]
Saxitoxins	Dinoflagellates: Alexandrium, Pyrodinium, Gymnodinium Cyanobacteria: Anabaena circinalis, Aphanizomenon sp., Aphanizomenon gracile, Cylindrospermopsis raciborskii, Lyngbya wollei	Carbamate alkaloids	block sodium channels in nerve axons	[9,16,19]
Dermatotoxins
Lyngbyatoxin-a	Lyngbya	Alkaloid	potent tumor promoters, acting through potentiation of protein kinase C (PKC)	[3,6]
Aplysiatoxin	Lyngbya, Schizothrix, Planktothrix (Oscillatoria)	Alkaloids	potent tumor promoters, acting through potentiation of protein kinase C (PKC)	[3,6]
Lipopolysaccharides (LPS)	Cyanobacteria in general	Lipopoly-saccharides	Inflammatory agents, gastrointestinal irritants	[3,21]