Astertarone A: A Triterpenoid Ketone Isolated from the Roots of Aster tataricus L.

The structure of astertarone A isolated from the root extract of Aster tataricus L. (Compositae) was established to be D : A-friedoeuph-21-en-3-one (1) based on spectroscopic methods. This is the first example of a naturally occurring triterpenoid with a D : A-friedoeuphane skeleton. Isolation and identification of epishinol (2), shionone (3), friedelin, epifriedelinol, and Ψ-taraxasterol are also described.