Asian Journal
Of Traditional Medicines

Abstract: Ixerin Z ( compound 1 ) and 11, 13a-dihydroixerin Z ( compound 2 ) are two known sesquiterpene lactone glycosides isolated from Crepidiastrum sonchifolium ( Bunge ) J.H. Pak & Kawano, which is used as a herbal medicine in Asia. In this study, compound 1 and 2 were first converted to sesquiterpene lactone aglycones 3-hydroxy-1 ( 10 ), 3, 11 ( 13 )-guaiatriene- 12, 6-olide- 2-one ( compound 3 ) and 3-hydroxy-
1 ( 10 ), 3-guaiadiene-12, 6-olide- 2-one ( compound 4 ) by hydrolysis. Then the antitumor effects of these four compounds were measured in vitro and in vivo. It was indicated by MTT assay that compound 3 and 4 inhibited various cultured cell growth in a dose-dependent manner. The possible mechanism of cytotoxicity was investigated on compound 3 and 4 with the observation that both of them could affect DNA replication by inhibiting the ssDNA binding activity of replication protein A ( RPA ) with the use of simian virus ( SV40 ) DNA in vitro replication system. Furthermore, it was also revealed in cell cycle analysis that compound 3 and 4 could arrest A549 cells in G 2 / M phase. All these results suggested that compound 3 and 4 could be potentially used in the development of anticancer drugs.

Key words: Crepidiastrum sonchifolium, Sesquiterpene lactone, Antitumor, DNA replication, RPA