A compound that inhibits the synthesis of the naturally occurring polyamines, intracellular compounds that bind to DNA and play a critical role in cell division, differentiation and membrane function. These inhibitors affect the activity of enzymes like ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMD) that are involved in the biosynthesis of polyamines. A reduction in intracellular polyamine concentration may lead to a decreased cell growth.