Panclicins, novel pancreatic lipase inhibitors. II. Structural elucidation.

Panclicins A-E are novel and potent pancreatic lipase inhibitors produced by Streptomyces sp. NR 0619. Their structures have been elucidated based on NMR and FAB-MS experiments. The relative configurations have also been determined by NMR experiments. The absolute stereochemistry has been determined by the chiral HPLC analysis of the hydrolysates of panclicins A and B and by modified Mosher's method on a derivative of panclicin A. They are structurally related to beta-lactone esterase inhibitors of microbial origin, lipstatin, valilactone, ebelactones and esterastin. Panclicins also contain a beta-lactone structure with two alkyl chains, one of which has an N-formylalanyloxy or N-formylglycyloxy substituent.