ChEBI: Picrotoxinin is a picrotoxane sesquiterpenoid that is 3a,4,5,6,7,7a-hexahydro-1H-indene-3,7-dicarboxylic acid which is substituted at positions 3a, 6, and 7a by methyl, isopropenyl, and hydroxy groups, respectively; in which the double bond at position 2-3 has been epoxidised; and in which the carboxy groups at positions 3 and 7 have undergone gamma-lactone formation by O-alkylation to positions 4 and 5, respectively. A component of picrotoxin. It has a role as a plant metabolite, a GABA antagonist and a serotonergic antagonist. It is an organic heteropentacyclic compound, an epoxide, a tertiary alcohol, a gamma-lactone and a picrotoxane sesquiterpenoid.
These neurotoxic GABAA receptor antagonists, consisting of a nearly 1:1
mixture of picrotoxinin, (FW = 292.29 g/mol; CAS 17617-45-7) and
picrotin (FW = 310.30 g/mol; CAS 124-87-8), is a bitter-tasting (hence the
Greek prefix picros) principle, also known as cocculin, from fishberry seeds
(Anamirta cocculus) and the Philippine bayating (Tinomiscium
philippinense). Picrotoxin binds to the chloride channel of the receptor
without displacing g-aminobutyric acid. Picrotoxin is highly toxic,
exerting both stimulant and convulsant effects, and care must be exercised
when handling this agent.
