Selective cytotoxic effects on cancer cell-lines of a protein fraction isolated from annona squamosa and containing ribosome inactivating proteins

A partially-purified protein fraction (PfaI) from Annona squamosa contains ribosome-inactivating protein (RIPs) which cleave supercoiled double stranded DNA and ribosomal RNA. Agents that cleave both DNA or RNA have potential anti-cancer activity. Pfal was screened against B-LCL EBV/NPC, Myeloma, and Raji cancer cell-lines compared with normal lymphocytes for selective cytotoxic effects. It caused 90% cytotoxity of cancer cells at a concentration of 0.1 gg/mL for B-LCL EBV/NPC and Raji cells and 1.0 ug/L for Myeloma cells. PfaI was much less toxic to normal lymphocytes (20% and 30% cytotoxity at 0.1 and 1.0 pg/mL respectively). Keywords: Annona squamosa � cytotoxicity � ribosome -inactivating proteins � cancer cell- line