Indoloquinoline alkaloids represent an important class of antimalarial, 
antibacterial and antiviral compounds. Indolo[2,3-b]quinolines are a family of 
DNA intercalators and inhibitors of topoisomerase II, synthetic analogs of 
neocryptolepine, an alkaloid traditionally used in African folk medicine. These 
cytotoxic substances are promising anticancer agents. Active representatives of 
indolo[2,3-b]quinolines affect model and natural membranes. The distinct 
structure and hydrophobicity of the compounds leads to marked differences in the 
disturbing effects on membrane organization and function. Our results also 
indicated a strong relationship between the presence of the chain and the Poct 
of the molecule as well as the capacity for incorporation into 
carboxyfluorescein-trapped liposomes in the 0.02-0.06 mM range. Moreover, a 
correlation between binding to neutral dimyristoylphosphatidylcholine (DMPC) or 
negative charged dimyristoylphosphatidylcholine:dimyristoylphosphatidylglycerol 
(DMPC:DMPG, 9:1 w/w) liposomes, as well as to erythrocyte ghosts and pKa, was 
also found. All the compounds cause hemolysis in isotonic conditions with 
concentration causing 50% hemolysis (HC50) in the 0.12-0.88 mM range. The 
concentration-dependent inhibitory effect of the tested agents on erythrocyte 
ghosts' acetylcholinesterase activity was also studied.