Tephrosin is a natural rotenoid which has potent antitumor activities. Tephrosin induces degradation of of EGFR and ErbB2 by inducing internalization of the receptors.In Vitro: Treatment of HT-29 cells with tephrosin (0-10μM) inhibits both the ligand-induced and constitutive phosphorylation of EGFR, ErbB2 and ErbB3, and concomitantly suppresses the activation of the downstream signaling molecules such as Akt and Erk1/2 mitogen-activated protein kinase (MAPK) .