Podophyllotoxin is a non-alkaloid toxin lignan extracted from the roots and rhizomes of Podophyllum species. It binds to topoisomerase II during the late S and early G2 stage, blocking tubulin polymerization and, thus, inhibiting mitosis. In addition to being used as a cathartic, purgative, antiviral agent, vesicant, and antihelminthic, podophyllotoxin is the starting material for the semi-synthesis of the anti-cancer drugs etoposide , teniposide , and etopophos.
