Peribysins A-D, potent cell-adhesion inhibitors from a sea hare-derived culture of Periconia species.

Peribysins A-D 1-4, including a new type of furanofuran, have been isolated from a strain of Periconia byssoides originally separated from the sea hare Aplysia kurodai, and their relative stereostructures have been elucidated on the basis of NMR spectral analyses. All these metabolites potently inhibited the adhesion of human-leukemia HL-60 cells to HUVEC. The activity of compound 4, exhibiting the most potent inhibitory activity, was 380 times as potent as herbimycin A (standard).