Oxygenated pimarane diterpenes from Kaempferia marginata

Six new diterpenes, (1R,2S,5S,7S,9R,10S,13R)-1,2,7-trihydroxypimara-8(14),15-diene (1), (1R,2S,5S,9S,10S,11-R,13R)-1,2,11-trihydroxypimara-8(14),15-diene (2), (1S,5S,7R,9R,IOS,11R,13R)-1,7,11-trihydroxypimara-8(14),15-diene (3), (1S,5S,9S,10S,11-R,13R)-1,11-dihydroxypimara-8(14),15-diene (4),(5S, 6R,9S,10S,13R)-6-hydroxypimara-8(14),15-diene-1-one (5), and (1R,2S,5S,7S,9R,IOS,13R)-1,2-dihydroxypimara-8(14),15-diene-7-one (6), along with four known diterpenes, have been isolated from the dichloromethane extract of whole plants of Kaempferia marginata. The structures were assigned by spectroscopic methods. The absolute configuration of 1 was established by the Mosher ester method. Substances obtained were evaluated against a panel of bioassays including antimalarial, antituberculous, and antifungal activity.