BIOACTIVE SATURATED PYRROLIZIDINE ALKALOIDS FROM HELIOTROPIUM-FLORIDUM

Here we describe the isolation and structural determination of the new saturated pyrrolizidine monoester alkaloids, 3'-acetyltrachelanthamin e, floridine, floridinine and floridimine, along with the known one, h eliovicine, from Heliotropium floridum. Their structures were establis hed by high resolution NMR (including 2D NMR experiments), mass spectr ometry, chemical reactions and by correlation with published data of k nown compounds. Bioassays of the alkaloidal extract and its major comp onents against several insect pests and plant pathogens showed that 3' -acetyltrachelanthamine is a strong anti-feedant, with low toxicity ag ainst Leptinotarsa decemlineata and a moderate anti-fungal agent again st Fusarium monoliforme; floridinine only showed the anti-fungal effec t. (C) 1997 Elsevier Science Ltd.