Microtubule stabilization agent that promotes tubulin polymerization and induces G2-M cell cycle arrest (EC50 = 32 nM in HeLa cells). Inhibits proliferation of human carcinoma cell lines in vitro, including MDR cells overexpressing the P-glycoprotein efflux pump. Exhibits potent cytotoxicity in MCF-7 and A549 cells (EC50 values are 0.3 and 2.7 nM respectively). Inhibits growth of HCT-15 tumors in mice in vivo. Purity 98%. MW (observed): 507.68