Isolation and anti-inflammatory activity evaluation of triterpenoids and a monoterpenoid glycoside from Harpagophytum procumbens.

A new triterpenoid glycoside, designated harproside (1), and a new iridoid glycoside, named pagide (2), along with six known triterpenoids (3-8), were obtained from the tubers of Harpagophytum procumbens D. C. (devil's claw), and their structures were established through chemical methods and spectroscopic analyses. In an in vitro assay, the six triterpenoids showed anti-inflammatory activity. Compounds 3, 7, and 8 showed significant inhibitory activity against neutrophil respiratory burst stimulated by PMA, while compounds 4, 5, and 6 showed marginal inhibitory activity.