The DNA intercalating alkaloid cryptolepine interferes with topoisomerase II and inhibits primarily DNA synthesis in B16 melanoma cells. - Bonjean,K.; De Pauw-Gillet,M.C.; Defresne,M.P.; Colson,P.; Houssier,C.; Dassonneville,L.; Bailly,C.; Greimers,R.; Wright,C.; Quetin-Leclercq,J.; Tits,M.; Angenot,L. (Biochemistry, 1998)