title: Effect of Inducers, Incubation Time and Heme Concentration on IC(50) Value Variation in Anti-heme Crystallization Assay.
abstract: Heme detoxification through crystallization into hemozoin has been suggested as a good target for the development of screening assays for new antimalarials. However, comparisons among the data obtained from different experiments are difficult, and the IC(50) values (the concentrations of drug that are required to inhibit 50% of hemozoin formation) for the same drug vary widely. We studied the effects of changes in heme concentration (precursor of β-hematin), incubation time and three inducers (SDS, Tween 20 and linoleic acid) on the IC(50) of some antimalarials (chloroquine, quinine, amodiaquine, and clotrimazole). The results showed that increasing both inducer concentration and incubation time raised the IC(50) of selected antimalarials. Any change in those factors caused the IC(50) value to vary. Standardization of assay conditions is, therefore, necessary to increase reproducibility and reduce discrepancies in assay performance. Considering all of the variables, the best choice of inducers is in the order of SDS > Tween 20 > linoleic acid.
authors.affiliation: Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
authors.forename: Nguyen Thanh Thuy
authors.initials: NT
authors.lastname: Nhien
authors.forename: Nguyen Tien
authors.initials: NT
authors.lastname: Huy
authors.forename: Dinh Thanh
authors.initials: DT
authors.lastname: Uyen
authors.forename: Eric
authors.initials: E
authors.lastname: Deharo
authors.forename: Pham Thi Le
authors.initials: PT
authors.lastname: Hoa
authors.forename: Kenji
authors.initials: K
authors.lastname: Hirayama
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Harada
authors.forename: Kaeko
authors.initials: K
authors.lastname: Kamei