Isolation and structures of acremolactones B and C, novel plant-growth inhibitory gamma-lactones from Acremonium roseum I4267.

Novel acremolactones B and C were isolated from the acremolactone A-producing Acremonium roseum I4267. The structure of acremolactone B having a phenylpyridyl gamma-lactone was elucidated by spectroscopic methods. It showed plant growth inhibitory activity toward Chinese cabbage seedlings. The congener of acremolactone C having a phenylcyclopentenone gamma-lactone showed weak activity.