Biol. Pharm. Bull. 28(6) 1025—1030 (2005)

eybees from the bud or bark of certain coniferous trees, has long been used in folk medicine. Several studies on the isolated chemical components of propolis have reported a number of biological responses including antibacterial, anti-fungal, anti-inflammatory and anti-tumor activities. In particular, 3,4-dihydroxycinnamic acid phenetyl ester (CAPE) displays various potent anti-tumor effects. CAPE suppresses TPAinduced tumor promotion, adenovirus E1A-mediated transformation and COX-2 expression, which contributes to neo-angiogenetic effects in the in situ tumor mass and inhibits immune responses. Cinnamic acid also exhibits antitumor activity, although somewhat weaker than CAPE. It is possible that other as yet unidentified chemical components of propolis, including cinnamic acid derivatives also exert anti-tumor activity. Baccharin and drupanin among the cinnamic acid derivatives which have prenyl moieties have been reported to possess tumoricidal activity and induce apoptosis against the myelocytic leukemia cell line HL60. Apoptosis plays an important role in the tumorcidal activity of chemotherapeutic agents. Baccharin and drupanin effectively kill leukemic cells through the apoptotic process, but the tumoricidal effects on other tumor cell lines have not been tested. Here we studied the in vitro tumoricidal activity of these two derivatives against various tumor cell lines. For in vivo experiments baccharin and drupanin were separately administered orally to DDY mice allografted with mouse sarcoma S-180. The results indicate that both compounds have in vitro tumoricidal activity against various cell lines and also in vivo activity against allografted sarcoma S180. Moreover, although baccharin and drupanin effectively induce a genotoxic effect on sarcoma S-180, normal splenocytes are less affected.