New carbazole alkaloids from Clausena anisata with antitumor promoting activity

Four new carbazole alkaloids, named clausamine D (1), E (2), F (3), and G (4), were isolated from Clausena anisata as inhibitors of Epstein-Barr virus early antigen activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells.