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U.S. Department of Health and Human Services

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BBB - Saxitoxin Structure

 

Bad Bug Book:
Foodborne Pathogenic Microorganisms and Natural Toxins Handbook
Saxitoxin


Bad Bug Book 2nd Edition: Shellfish toxins (PSP, DSP, NSP, ASP, AZP)

Molecular structure of saxitoxin groups: carbamates (most potent), decarbamoyl toxins (intermediate in toxicity; usually present in shellfish but not toxigenic algae), N-sulfocarbamoyl toxins (less potent), and hydroxybenzoate toxins (more recently recognized group of PSP toxins, shown to be specific to the dinoflagellate Gymnodinium catenatum). Toxins in the saxitoxin family may be produced by a range of dinoflagellates, including species in the genera Alexandrium, Gymnodinium, and Pyrodinium. There are also reports of STXs being produced by certain freshwater and brackish cyanobacteria as well as calcareous red macro algae. The traditional route of exposure is accumulation in filter-feeding shellfish.

 

Chemical Structure of Saxitoxin and derivatives (final, transparent) 

R1R2R3Carbamate
Toxins
Decarbamoyl
Toxins
N-sulfocarbamoyl
Toxins
Hydroxybenzoate
Toxins
HHHSTXdc-STXB1GC3
OHHHNEOdc-NEOB2 
OHHOSO3-GTX 1dc-GTX 1C3 
HHOSO3-GTX 2dc-GTX 2C1GC1
HOSO3-HGTX 3dc-GTX 3C2GC2
OHOSO3-HGTX 4dc-GTX 4C4 
   R4:
Saxitoxin structure: carbamate group (transparent)
R4:

Saxitoxin structure: OH group (decarbamoyl) (transparent)
R4:
Saxitoxin structure: group: N-sulfocabamoyl group (transparent)
R4:
Saxitoxin structure: group: hydroxybenzoate group (transparent)