The molecule is a tricyclic diterpenoid having formula C30H48O5, originally isolated from the bark of Tripterygium wilfordii. It is a hexacyclic triterpenoid, a diol, a hydroxy monocarboxylic acid and a cyclic hemiketal. It derives from a hydride of a friedelane.
(1R,4S,5R,8S,11R,13R,14S,17R,18S,20R,21R,24R)-20,21-dihydroxy-5,8,11,14,17,24-hexamethyl-22-oxahexacyclo[19.2.1.01,18.04,17.05,14.08,13]tetracosane-11-carboxylic acid