Spinosyn insecticides

Abstract

The spinosyns found in the bacterial species Saccharopolyspora spinosa were first isolated from a soil sample from an abandoned rum distillery on the British Virgin Islands. Their anti-insecticidal activity against several commercially relevant pests is based on the allosteric, agonistic binding at the nicotinic acetylcholine receptor and an antagonistic effect on the γ-aminobutyric acid receptor. Spinosyns result from the polyketide pathway. The biosynthesis of the tetracyclic lactone comprises an enzymatic Diels–Alder and a Rauhut–Currier-like reaction followed by glycosylation with rhamnose and forosamine. The spinosyns, constituting the insecticidal active ingredients in Spinosad® and Spinetoram® from Dow AgroSciences, are manufactured by fermentation. However, in recent years, facilitated by computer-aided molecular modeling and bioactivity directed synthesis, novel highly potent, structurally simplified spinosyn analogs were discovered, which might be accessible in the future by total synthesis on an industrial scale. © 2020, Springer Nature Switzerland AG.