The present invention is directed to derivatives of gambogic acid and analogs thereof. Exemplary gambogic acid derivatives of the present invention include, among others, derivatives substituted in the C10 and C28 positions of gambogic acid. The present invention also relates to the discovery that certain preferred compounds of the present invention are activators of caspases and inducers of apoptosis. Therefore, the activators of caspases and inducers of apoptosis of this invention can be used to induce cell death in a variety of clinical conditions in which uncontrolled growth and spread of abnormal cells occurs.