A New Taraxastane-type Triterpenoid from Cleistocalyx operculatus.

Ten known compounds including a chalcone, a long-chain alcohol, two flavonols, and six triterpenoids/steroids together with a new taraxastane-type triterpenoid, named cleistocalyxin, were isolated from the leaves of Cleistocalyx operculatus. The structure of cleistocalyxin was determined on the basis of IR, MS and NMR spectroscopic methods.