Abstract
The SYBR green I (SG) dye-based fluorescence assay for screening antimalarial compounds is based on direct quantitation of parasite DNA. We show that DNA-interacting cationic cell-penetrating peptides (CPPs) and intercalating agents compete with SG dye to bind to DNA. Therefore, readouts of this assay, unlike those of the [(3)H]hypoxanthine incorporation assay, for the antimalarial activity of the above DNA binding agents may be erroneous. In the case of CPPs, false readouts can be improved by the removal of excess peptides.