Sesquiterpene lactones from Crepis cameroonica (Asteraceae).

In addition to one known compound, 3beta,8alpha-dihydroxyguaian-4(15),10(14),11(13)-trien-6,12 olide (8-desacylcynaropicrin) (3), two new sesquiterpene lactones have been isolated from the aerial parts of Crepis cameroonica. By means of spectroscopic analysis, the structures and relative configurations of the new compounds were established as 3beta,9beta-dihydroxyguaian-4(15),10(14),11(13)-trien-6,12 olide (1) and 8alpha-hydroxy-4alpha(13),11beta(15)-tetrahydrozaluzanin C (2). The in vitro antimicrobial spectrum of pure compounds and crude extracts are also reported.