Rearranged abietane diterpenoid hydroquinones from aerial parts of Ajuga decumbens Thunb

► Four rearranged abietane diterpenoids were first found from Ajuga decumbens. ► The structure of new compounds was determined by spectroscopic methods. ► The structure of ajudecumin A was also verified by X-ray diffraction analysis. ► Ajudecumins A and C moderately inhibited the proliferation of MCF-7 cells.