Isopimarane-type diterpenoids from the rhizomes of <i>Kaempferia galanga</i> L. and their biological activities

Fourteen isopimarane diterpenoids ( 1 - 14 ) were isolated from the rhizomes of Kaempferia galanga , including four new compounds ( 1 - 4 ). The isolated secondary metabolites were identified through analysis of spectroscopic (1 D and 2 D NMR) and mass spectrometric data, together with X-ray diffraction studies. Compounds 4 - 5 , 7 - 11 , and 13 showed strong antimalarial activities, with IC 50 values in the range of 1.46-3.99 μ g/mL. Moreover, compounds 4 , 5 , 8 , and 12 showed cytotoxicity against KB cell line with IC 50 values in the range of 6.13-38.2 μ g/mL, while compounds 4 , 5 , and 12 showed cytotoxicity against MCF-7 cell line with IC 50 values in the range of 11.75-47.4 μ g/mL. Eventually, the isolated compounds were screened against six bacterial strains and Mycobacterium tuberculosis , demonstrating weak to moderate activities.