Two novel bis-labdanic diterpenoids named calcaratarin D and calcaratarin E were isolated
from the rhizomes of Alpinia calcarata. Their structures were elucidated as a pair of stereoisomers on the basis of the spectral
evidence. 2D NMR techniques including 1H-1H COSY, HMQC, HMBC, NOESY spectra and HRFABMS were extensively applied to establish
the structures. The two bis-labdanic diterpenoids showed cytotoxic activity against
human KB cells in vitro.
Alpinia calcarata.
- Zingiberaceae - bis-labdanic diterpenoids - calcaratarin D - calcaratarin E - cytotoxic
activity