Fulvene-5 is a chemical compound that exhibits antitumor activity. It functions as a potent inhibitor of NADPH oxidase 4 (NOX4) and possesses antioxidant properties. Additionally, Fulvene-5 acts as a reactive oxygen species (ROS) modifying agent and a powerful radioprotector.

Fulvene-5 (0.5-1.0 μM) treatment decreases the expression of Ang2, delta-like ligand 4 (DLL4), placental growth factor (PLGF), and Nrarp in a dose-dependent manner in bEnd.3 cells.Fulvene-5 (10?μM; 1 hour) facilitates the reversal of HCT116 TP53 wild type (WT) and HCT116 isogenic TP53 null mutant (Mut) cell cultures adaptive responses from pro-survival to radio-sensitization and vice versa. These changes are accompanied by corresponding reversals in the translocation of survivin to the nuclei of TP53 WT and to the cytoplasm of TP53 Mut cells. The potential role of NOX4 in the expression of the survivin-associated adaptive response is investigated by transfecting HCT116 cells with NOX4 siRNA oligomers to inhibit NOX4 expression. Under these conditions NOX4 expression is inhibited by about 50%.

Fulvene-5??treatment potently inhibits hemangioma growth in mice.