Paraherquamide A is a mycotoxin anthelmintic originally isolated from P. paraherquei. It binds to acetylcholine receptors (IC50 = 0.5 nM for head homogenates of M. domestica) and acts as an antagonist. Paraherquamide A is toxic to C. elegans (LD50 = 2.5 μg/ml) and effective against T. colubriformis infection in gerbils when used at doses ranging from 0.39 to 200 mg/kg. It is toxic to mice (LD50 = 14.9 mg/kg).
Paraherquamide A is a selective, competitive, cholinergic antagonist.
Paraherquamide A was first reported as a mycotoxin related to the indole tremorgenic mycotoxins. Subsequent research identified a potent, non-toxic paralysis of nematodes which led to the metabolite's development as a candidate anthelmintic. Paraherquamide A is a selective, competitive, cholinergic antagonist that distinguishes subtypes of cholinergic receptors.