Two new pimarane diterpenes were obtained from Kaempferia marginata rhizomes, which are 1α-acetoxysandaracopimaradien-2-one (1) and 1α-acetoxysandaracopimaradiene (4), along with seven known compounds from the hexane and chloroform fractions including two pimarane-type diterpenes [marginatol (5), sandaracopimaradiene (8)], one kavalactone [desmethoxyyangonin (3)], three steroids [sitosterol-β-D-glucoside (2), the mixture of stigmasterol and β-sitosterol (6 + 7)] and one diarylheptanoid [bisdemethoxycurcumin (9)]. Compounds 3 and 9 exhibited potent effect against NO production with IC50 of 10.1 and 6.8 µM, respectively. Compound 3 inhibited iNOS mRNA expression in a dose-dependent manner, while 9 suppressed both of iNOS and COX-2 genes. Moreover, compounds 2, 3, 6 + 7 and 9 were isolated for the first time from K. marginata. These results revealed that diterpenes, diarylheptanoid and kavalactone are components of K. marginata that afford anti-inflammatory effect through a mechanism involving a decrease in inflammatory mediators.
