IN-VITRO ANTIPLASMODIAL, ANTIAMEBIC, AND CYTOTOXIC ACTIVITIES OF A SERIES OF BISBENZYLISOQUINOLINE ALKALOIDS

Twenty-four bisbenzylisoquinoline alkaloids were screened for antiplas modial, antiamoebic, and cytotoxic activities by use of in vitro micro tests. Eight of the alkaloids had antiplasmodial activity, with a 50% inhibitory concentration (IC50) of less than 1 muM against a multidrug -resistant strain of Plasmodium falciparum (chloroquine had an IC50 of 0.2 muM). The three alkaloids most active against Entamoeba histolyti ca, aromoline, isotrilobine, and insularine, had IC50s of 5 to 11.1 mu M (metronidazole had an IC50 of 1.87 muM). None of the 24 bisbenzyliso quinoline alkaloids exhibited significant cytotoxicity against the KB cell line, the most toxic being berbamine, with an IC50 of 17.8 muM (t he IC50 of podophyllotoxin was 0.008 muM). Bisbenzylisoquinoline alkal oids merit further investigation as potential novel antimalarial agent s.