A new labdane diterpene from Leonurus heterophyllus

A new labdane diterpene, heteronone B (1), together with a known labdane diterpene, heteronone A (2), have been isolated from the aerial part of Leonurus heterophyllus. Their structures were established mainly by 1D and 2D NMR analysis and the stereochemistry of 2 was confirmed by single-crystal X-ray diffraction analysis.