Radiclonic acid is a polyketide produced by Penicillium and Talaromyces species originally isolated from the mycelial extract of an unidentified fungus by Sassa and coworkers at Yamagata University, Japan in 1973. Radiclonic acid is an acetylcholinesterase inhibitor and plant growth regulator, promoting root elongation in many types of seedlings. In cabbage seedlings, radiclonic acid is active at 25 ppm. In rice seedlings, radiclonic acid promotes growth below 100 ppm, but is inhibitory at higher concentrations. Radiclonic acid was patented by Sankyo in 1975.