STUDIES ON THE ANTI-TUMOR-PROMOTING ACTIVITY OF NATURALLY-OCCURRING SUBSTANCES .4. PD-II [(+)ANOMALIN, (+)PRAERUPTORIN-B], A SESELIN-TYPE COUMARIN, INHIBITS THE PROMOTION OF SKIN TUMOR-FORMATION BY 12-O-TETRADECANOYLPHORBOL-13-ACETATE IN 7,12-DIMETHYLBENZ[A]ANTHRACENE-INITIATED MICE

Since Pd-II [(+)anomalin, (+)praeruptorin B], a seselin-type coumarin, was found to inhibit tumor promoter induced phemonenon in vitro, the effect of Pd-II on the in vivo tumorpromoting action of 12-O-tetradecanoylphorbol-13-acetate (IPA) in 7,12-dimethylbenz[a]anthracene-initiated mouse skin was investigated. Pd-II, applied 40 min before the TPA treatment, at a dose of 10 μmol/painting, completely suppressed tumor formation up to 20 weeks of tumor promotion, without any toxicity. Besides Pd-II, various antitumor-promoter coumarins were found in the traditional Chinese medicine Qian-Hu, from which Pd-II was obtained. These coumarins may be useful for the development of an effective method to prevent cancer. © 1990 Oxford University Press.