Two new monoterpene esters from the pericarps of Alpinia zerumbet

Two new monoterpene esters (1 and 2) and four known compounds (3-6) were isolated from the pericarps of Alpinia zerumbet. Their structures were elucidated by extensive spectroscopic analyses and their anti-inflammatory activity was evaluated by monitoring their inhibitory effects on the interleukin-1 beta-induced production of nitric oxide in primary cultured rat hepatocytes. The new compound 1 and cardamonin 3 showed inhibitory activities with IC50 values of 17.6 +/- 1.1 and 10.2 +/- 1.3 mu M, respectively, which are comparable to that of the positive control N-G-methyl-L-arginine acetate salt.