Abstract
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.
Acknowledgements
The authors wish to thank Ms. Wen Li and Mr. Yi Sha of the Analytical Center of Sheng Yang Pharmaceutical University for recording the 1H-NMR and 13C-NMR spectra, and Dr. Xue-Mei Niu, Sam-Hip Tsai and Ming Zhao (SCM of CUHK) for very helpful discussions.