Abstract
Studies were carried out to screen Toona ciliata M. J. Roemer (Meliaceae) for its cytotoxicity and antitumor activity. The crude extracts and a major isolate, siderin, obtained from the petroleum ether extract of T. ciliata were found to exhibit significant cytotoxicity in the brine shrimp lethality bioassay. In the potato disc bioassay, the extracts and the fractions demonstrated mild to moderate antitumor activity. The results were compared with those produced by vincristine sulphate.