Absolute stereostructures of cell-adhesion inhibitors, peribysins A, E, F and G, produced by a sea hare-derived Periconia sp.

Peribysins E similar to G (1 similar to 3) have been isolated from a strain of Periconia byssoides originally separated from the sea hare Aplysia kurodai. Their absolute stereostructures have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques and some chemical transformations. In addition, the absolute configuration of peribysin A (4), previously undetermined, has been established by conversion to 2 and 3. All these metabolites inhibited the adhesion of humanleukemia HL-60 cells to HUVEC.