Development in Assay Methods for in Vitro Antimalarial Drug Efficacy Testing: A Systematic Review

Abstract

The emergence and spread of drug resistance are the major challenges in malaria eradication mission. Besides various strategies laid down by World Health Organization, such as vector management, source reduction, early case detection, prompt treatment, and development of new diagnostics and vaccines, nevertheless the need for new and efficacious drugs against malaria has become a critical priority on the global malaria research agenda. At several screening stages, millions of compounds are screened (1,000–2,000,000 compounds per screening campaign), before pre-clinical trials to select optimum lead. Carrying out in vitro screening of antimalarials is very difficult as different assay methods are subject to numerous sources of variability across different laboratories around the globe. Despite this, in vitro screening is an essential part of antimalarial drug development as it enables to resource various confounding factors such as host immune response and drug–drug interaction. Therefore, in this article, we try to illustrate the basic necessity behind in vitro study and how new methods are developed and subsequently adopted for high-throughput antimalarial drug screening and its application in achieving the next level of in vitro screening based on the current approaches (such as stem cells).

In vitro anti-malarial efficacy of chalcones: cytotoxicity profile, mechanism of action and their effect on erythrocytes

“…Though this morphological microscopic method is cumbersome and labour intensive, it has been established because of its reproducibility and simplicity. It is also an inexpensive assay in comparison to the various other anti-malarial assays like [ 3 H]-hypoxanthine incorporation assay, lactate dehydrogenase (pLDH) assay, Malaria SYBR Green I-based fluorescence (MSF) assay, double-site enzyme-linked lactate dehydrogenase enzyme immunodetection (DELI) assay, flow cytometric haemozoin detection assay, luciferase-based high-throughput screening (HTS) assay [39, 40], that can be set up in smaller laboratories. The evidence for the anti-malarial activity of chalcones from natural [16, 18, 41] and synthetic source is well documented [42–48].…”

Rapid and quantitative antimalarial drug efficacy testing via the magneto-optical detection of hemozoin

“…Since it excludes a range of host-specific effects influencing treatment efficacy, in vitro testing is an essential tool to study drug resistance, facilitating high reproducibility due to well-controlled measurement conditions. Various methods have been developed in order to make in vitro drug susceptibility testing faster, lower-cost and more convenient 5 . The targets of antimalarial drug treatment are the asexual intraerythrocytic life-cycle stages of the parasites, and in vitro drug susceptibility assays quantify the maturation and multiplication of these stages under drug effect.…”

Progress and challenges in the use of fluorescence‐based flow cytometric assays for anti‐malarial drug susceptibility tests

“…In addition to DNA synthesis-based assays, Plasmodium parasites in intraerythrocytic stages also actively synthesize cell membranes composed of phospholipids; thus, an assay based on incorporation of the radioisotope-labeled phospholipid precursor ethanolamine was developed [ 24 ], allowing an assessment of anti-malarial compounds targeting enzyme functioning in fatty acid biosynthesis [ 25 ]. Apart from biosynthesis-based tests, measurements of Plasmodium -specific lactate dehydrogenase [ 26 – 28 ] and histidine-rich protein II [ 29 , 30 ] are also available and have been widely used for anti-malarial drug tests [ 31 , 32 ].…”