Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10533240 | Analytical Biochemistry | 2005 | 14 Pages |
Abstract
Antimalarial drugs such as chloroquine are believed to act by inhibiting hemozoin formation in the food vacuole of the malaria parasite. We have developed a new assay for measuring and detecting inhibition of synthetic hemozoin (β-hematin) formation. Aqueous pyridine (5% v/v, pH 7.5) forms a low-spin complex with hematin but not with β-hematin. Its absorbance obeys Beer's law, making it useful for quantitating hematin concentration in hematin/β-hematin mixtures, allowing compounds to be investigated for inhibition of β-hematin formation. The assay is rapid (60 min incubation) and requires no centrifugation. The β-hematin inhibition data show good agreement with alternative assay methods reported by four laboratories. The assay was adapted for high-throughput colorimetric screening, allowing visual identification of β-hematin inhibitors. In this mode, the assay successfully detected all 18 β-hematin inhibitors in a set of 47 compounds tested, with no false positive results. The quantitative in vitro antimalarial activities of a set of 13 aminoquinolines and quinoline methanols were found to correlate significantly with β-hematin inhibition values determined using the assay.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Kanyile K. Ncokazi, Timothy J. Egan,