Simple and Inexpensive Fluorescence-Based Technique for High-Throughput Antimalarial Drug Screening

TLDR

Radioisotopic assays are costly, multi‑step, require specialized equipment and radioactivity safety, making them unsuitable for high‑throughput antimalarial drug screening. This study introduces a simple, robust, inexpensive one‑step fluorescence assay for antimalarial drug screening. The assay uses SYBR Green I, a dye that fluoresces strongly upon binding Plasmodium DNA, and compares its EC50 determinations with a standard radioisotopic method on *P. falciparum* D6 using known antimalarials over 48 h.

Abstract

ABSTRACT Radioisotopic assays involve expense, multistep protocols, equipment, and radioactivity safety requirements which are problematic in high-throughput drug testing. This study reports an alternative, simple, robust, inexpensive, one-step fluorescence assay for use in antimalarial drug screening. Parasite growth is determined by using SYBR Green I, a dye with marked fluorescence enhancement upon contact with Plasmodium DNA. A side-by-side comparison of this fluorescence assay and a standard radioisotopic method was performed by testing known antimalarial agents against Plasmodium falciparum strain D6. Both assay methods were used to determine the effective concentration of drug that resulted in a 50% reduction in the observed counts (EC 50 ) after 48 h of parasite growth in the presence of each drug. The EC 50 s of chloroquine, quinine, mefloquine, artemisinin, and 3,6-bis-ε-( N , N -diethylamino)-amyloxyxanthone were similar or identical by both techniques. The results obtained with this new fluorescence assay suggest that it may be an ideal method for high-throughput antimalarial drug screening.