Potential Anticancer Activity of Naturally Occurring and Semisynthetic Derivatives of Aculeatins A and B from Amomum aculeatum

Activity-guided fractionation of hexanes- and CHCl 3-soluble extracts of Amomum aculeatum leaves, collected in Indonesia, led to the isolation of three new dioxadispiroketal-type ( 3- 5) and two new oxaspiroketal-type ( 6 and 7) derivatives. Nine semisynthetic derivatives ( 1a- 1h and 2a) of the parent compounds, aculeatins A ( 1) and B ( 2), were prepared. All isolates and semisynthetic compounds were tested against a small panel of human cell lines. Of these, aculeatin A ( 1; ED 50 0.2-1.0 microM) was found to be among the most cytotoxic of the compounds tested and was further evaluated in an in vivo hollow fiber assay; it was found to be active against MCF-7 (human breast cancer) cells implanted intraperitoneally at doses of 6.25, 12.5, 25, and 50 mg/kg. However, when 1 was tested using P388 lymphocytic leukemia and human A2780 ovarian carcinoma in vivo models, it was deemed to be inactive at the doses used.