Synthesis and cytotoxic activity of substituted luotonin A derivatives.
Dallavalle S, Merlini L, Beretta GL, Tinelli S, Zunino F.
Luotonin A is a cytotoxic alkaloid that has been shown to inhibit topoisomerase I via stabilization of the binary complex topoisomerase-DNA in the same fashion as camptothecin. The synthesis and the cytotoxic activity on the lung carcinoma cell line H460 of a series of derivatives of Luotonin A is reported. The compounds inhibit topoisomerase I but show weak cytotoxic activity, thus confirming the peculiarity of ring E of camptothecin for antitumor activity.