4-Hydroxy-4,6a,6b,9,9,12a,14b-heptamethylperhydropicen-3-one hemihydrate isolated from Adiantum incisum.

The title compound, C(29)H(48)O(2)·0.5H(2)O, is a triterpenoid isolated from the stems and rhizomes of Adiantum incisum. The basic skeleton of the mol-ecule contains five six-membered rings, all adopting chair conformations, bearing a total of seven methyl, one hydroxyl and a keto group. There are two mol-ecules of the triterpene and one water molecule of crystallization in the asymmetric unit. The two unique triterpenoid mol-ecules hydrogen-bond directly via an O-H⋯O=C inter-action, and are also bridged by the water mol-ecule. The water also bridges to another pair of hydrogen-bonded triterpenoid mol-ecules.