A simplified procedure for the isolation of gram quantities of illudinM from culture broths of basidiomycete Omphalotus olearius is described. Esters of illudinM with docosahexaenoic acid, chlorambucil, demethylcantharidinic acid (endothall) and 2,2'-bipyridyl-5,5'-dicarboxylic acid were synthesised and tested for cytotoxicity and induction of apoptosis in two clinically relevant tumour cell lines