Abstract Homocamptothecin (hCPT) is an E-ring modified camptothecin (CPT) analogue, which showed pronounced inhibitory activity of topoisomerase I. In search of novel hCPT- type anticancer agents, two series of hCPT derivatives were synthesized and evaluated in vitro against three human tumor cell lines. The results indicated that the 10-substituted hCPT derivatives had a considerably higher cytotoxic activity than the 12-substituted ones. ...