Iridoids and lignans from Valeriana jatamansi.

Thirteen new iridoids including seven iridolactones, jatamanins A-M (1-13), and a new lignan, (+)-9'-isovaleroxylariciresinol (14), together with seven known iridoids and 13 lignans were obtained from whole plants of Valeriana jatamansi. Structures of the new compounds were determined by spectroscopic and crystallographic methods, and the absolute configuration of compound 1 was assigned by application of the modified Mosher method. Jatamanins H (8) and I (9) are iridolactones with an unusual C-8-C-11 oxygen bridge, forming a cage-like structure. (+)-9'-Isovaleroxylariciresinol (14) showed significant in vitro cytotoxicity against PC-3M and HCT-8 cell lines, with IC(50) values of 8.1 and 5.3 microM, respectively.