Putaminoxins D and E from Phoma putaminum

Two 10-macrolides, named putaminoxins D and E, were isolated together with other recently identified toxic putaminoxins from culture filtrates of Phoma putaminum, the causal agent of leaf necrosis of Erigeron annuus, a common weed found in fields and pastures. Putaminoxins D and E were characterized by spectroscopic and chemical methods as a new disubstituted nonen- and nonanolide, respectively. Moreover, 5-O-formylputaminoxin was isolated as an artefact from the culture filtrates acidified with formic acid. When they were assayed on leaves of host and non-host plants, putaminoxins D and E and 5-O-formylputaminoxin showed no toxicity, unlike other putaminoxins.