Azadirachtin, a scientific gold mine.

Azadirachtin is a highly interesting compound both for its chemical structure, which required 18 years to solve, and its synthesis, which required another 22 years, and for its biological properties as a feeding deterrent for many insects and a growth disruptant for most insects and many other arthropods. Its mode of action, structure-activity relationships, and its biosynthesis still require much research. A valuable natural pesticide, it has very low toxicity for vertebrates, and yet it has still not achieved a prominent place among pesticides and in many countries it is not yet licensed for use. An attempt is made to understand its failure to capture a larger market, 40 years after its discovery.