Cytotoxic quassinoids from Cedronia granatensis

The NCI in vitro primary disease-oriented antitumor screen has been used to select and guide the fractionation of the organic and aqueous extracts of Cedronia granatensis. Two quassinoids, sergiolide [1] and isobrucein B [2], to which the screening panel cell lines exhibited up to a 1000-fold range of differential sensitivity, were isolated. At concentrations of 10(-5)-10(-8) M, the compounds typically produced LC50-level responses against a majority of the melanoma lines and several of the colon, lung, and other solid tumor lines. These and related quassinoids may, therefore, be of interest for in vivo evaluation in appropriate xenograft tumor models.