The invention provides novel apoptosis-inducing compounds that include isolated, purified isoapoptolidin, and selectively functionalized isoapoptolidin derivatives and stereoisomers thereof; selectively functionalized apoptolidin derivatives and stereoisomers thereof; and deglycosylated isoapoptolidin and selectively functionalized derivatives and stereoisomers thereof. The isoapoptolidin, apoptolidin, and deglycosylated isoapoptolidin derivatives may be functionalized by substituting any or all of the methoxyl or hydroxyl groups of the parent molecule. Pharmaceutical compositions and methods for using the compounds are also provided.