Cyclopiazonic acid Facts Sheet

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Cyclopiazonic acid is a  specific inhibitor of Ca2+-ATPase in the intracellular Ca2+ storage sites.

Cyclopiazonic acid is a Mycotoxin,

Cyclopiazonic acid formula: C20H20N2O3

Cyclopiazonic acid is produced by   Penicillium cyclopium

Cyclopiazonic acid Molecular Weight : 336.39.
Cyclopiazonic acid Melting Point : 245 C.
Cyclopiazonic acid is soluble  in   chloroform and DMSO.
Cyclopiazonic acid is sold as white to off-white hygroscopic powder.
Cyclopiazonic acid Chemical Name is (6aa,10z, 11ab, 11ba)-6a,7,11a,11b-tetrahydro-10-(1-hydroxyethylidene)-7,7- dimethyl-6H-pyrrolo [1',2':2,3]isoindolo [4,5,6-cd]indole-9,11 (2H,10H)-dione.

Cyclopiazonic acid Biological Activity :
CPA is a highly selective inhibitor of Ca2+ - ATPase in skeletal muscle sarcoplasmic reticulum [3].
stimulates release of Ca2+ from intracellular stores by increasing plasma membrane Ca2+ permeability without increasing intracellular inositol (1,4,5)-triphosphate levels. inhibits the Ca2+ uptake: by sarcoplasmic vesicles prepared from skeletal muscle [4], by intracellular stores sites caffeine-sensitive in guinea-pig smooth muscle cells (3M) [6]; IC50 around 0.6 M in skinned smooth muscle fibres of the longitudinal layer of the guinea-pig ileum [5].
causes selective and reversible strong suppression of Ca2+-dependent K+ current in guinea-pig ileal and urinary bladder smooth muscle cells. It is effective in intact cells and can be washed out [1].
Its mechanism of action may be the following: decreases Ca2+ uptake by the inhibition of Ca2+ -pump in the sarcoplasmic and endoplasmic reticulum, decreases the subsequent Ca2+ release from these storage sites and, thereby, reduces the Ca2+ dependent K+ current [1].
Cyclopiazonic acid Toxicity (LD50)  in rat (orally): 36 mg/kg;.
Cyclopiazonic acidStorage recommendations : it is stable in dry state, store at +4C, avoiding humidity.


  1. Cyclopiazonic acid, an inhibitor of the sarcoplasmic reticulum Ca(2+)-pump, reduces Ca(2+)-dependent K+ currents in guinea-pig smooth muscle cells
  2. Cyclopiazonic acid depletes intracellular Ca2+ stores and activates an influx pathway for divalent cations in HL-60 cells.
  3. Interaction of cyclopiazonic acid with rat skeletal muscle sarcoplasmic reticulum vesicles. Effect on Ca2+ binding and Ca2+ permeability.

  4. Toxicological evaluations of cyclopiazonic acid and ochratoxin A in broilers.

  5. Age and growth-related changes in cyclopiazonic acid-potentiated lipophilic cation accumulation by cultured cells and binding to freeze-thaw lysed cells



[top] This page was done by a student of Bioinformatics, Open University Jerusalem Israel, in a homage to Fermentek and to Dr Berend.
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