Bufalin

Bufalin is a cardiotonic steroid first isolated from toad venom and used in traditional Asian medicine.{29917,29914} It inhibits the Na+/K+-ATPase transporter (Kds = 42, 45, and 40 nM for the ?1, ?2, and ?3 subunits, respectively).{29469} Intravenously administered bufalin is cleared rapidly, with a plasma half-life of 25 minutes in dogs and rats.{29913} Bufalin inhibits steroid receptor coactivator 1 (SRC-1) and SRC-3 at doses as low as 5 nM, promotes the degradation of SRC-3 protein, and inhibits cancer cell growth both in vitro and in vivo.{25457} It can also impact the action and expression of several other proteins and kinases as well as induce apoptosis in various cancer cells.{29915,29916}