Further labdane diterpenoids isolated from Leonurus persicus

Seven new labdane diterpenoids, leopersin G−L (1−4, 6−7) and 15-epi-leopersin J (5), and two known ones, 13-hydroxyballonigrinolide (8) and ballotenol (9), were isolated from the aerial parts of Leonurus persicus along with β-sitosterol and stigmasterol. The structure determinations were mainly based on 1D and 2D NMR spectra. The stereochemical configuration of ballotenol (9) was reestablished by 2D ROESY spectroscopy and by single-crystal X-ray diffraction analysis