Anthracenones and anthraquinones from roots of five species of the genus Karwinskia

A new polyphenolic anthracenone has been isolated from the roots of K. umbellata, K. subcordata, K. humboldtiana, K. mollis and K. johnstonii together with three known structural analogues. The new compound has been characterized as 7-[3′,4′-dihydro-9′-methoxy-1′,3′-dimethyl-10′-hydroxy-1 H′-naphtho[2′,3′, c′]pyran-5′-yl]- 3,4-dihydro-3-methyl-3,8,9-trihydroxy-1(2 H)-anthracenone. The chemical shifts of the 13CNMR spectra of this anthracenone and a related anthraquinone are reported.