Mode of action of p-quinone derivatives with trypanocidal activity studied by experimental and in silico models

Multifunctional Organometallic Compounds Active against Infective Trypanosomes: Ru(II) Ferrocenyl Derivatives with Two Different Bioactive Ligands

“…This study employed a redox-reporter cell line of bloodstream parasites that expresses a redox-sensitive variant of the Green Fluorescent Protein (roGFP2). The fluorescence spectrum of roGFP2 undergoes ratiometric changes reflecting the intracellular balance between oxidized and reduced low-molecular-weight thiols and has been successfully used to disclose the mode of action of structurally divergent compounds against different components of the trypanosome’s thiol-redox metabolism. − First, the functionality of the reporter cell line was confirmed using membrane-permeable thiol oxidizing (diamide) and reducing (dithiothreitol: DTT) agents, as described in the corresponding Experimental Section and the legend of Figure B. Next, the reporter parasites were exposed to the compound added at its EC 50 value for 1 h (sublethal condition).…”

“…Instead, it is tempting to speculate that the Ru complexes potentially interact and inhibit enzymes controlling redox homeostasis. Nonetheless, the magnitude of this redox change was lower than that triggered by compounds targeting specific components of the trypanosome redox system, − which suggests that the new Ru-complexes may affect other metabolic pathways that contribute to the blockage of trypanosomal growth. In this respect, biochemical assays and in silico analysis led to the insight that the compounds have an inhibitory effect on NADH-dependent fumarate reductase from T. cruzi .…”

“…The assay protocol has been reported previously and is briefly described here . Bloodstream T. b. brucei (strain 427, cell line 449) expressing the redox biosensor hGrx1-roGFP2 was grown in HMI-9 medium supplemented with 10% (v/v) FBS, 0.2 μg/mL phleomycin, 5 μg/mL hygromycin, 100 U/mL penicillin/100 μg/mL streptomycin in a humidified incubator with 5% CO 2 and at 37 °C.…”

Development of bioluminescent reporter Trypanosoma cruzi and bioassay for compound screening

“…Thirteen of them corresponded to compounds not yet tested against T. cruzi (12 benzoisothiazolones and 1 rotenoid, which is one of the singletons), whereas the remaining ones corresponded to previously characterized molecules (2 quinones, 4 sesquiterpene lactones and 1 platinum complex). Restricting the analysis to the last group, the two quinones identified as hits were recently shown to have sub-µM EC 50 against T. cruzi amastigotes (compounds 9 and 14 in (Ballesteros-Casallas et al, 2023). All sesquiterpene lactones assayed displayed anti-T. cruzi activity (cell viability ≤61%) and the two most potent: helenalin acetate (2% viability) and budlein A (26% viability), have already been reported to be one-digit μM inhibitors of T. cruzi amastigotes (EC 50 = 6.93 μM and 1.75 μM, respectively; Schmidt et al, 2002;.…”

DataSheet1.pdf

“…Thirteen of them corresponded to compounds not yet tested against T. cruzi (12 benzoisothiazolones and 1 rotenoid, which is one of the singletons), whereas the remaining ones corresponded to previously characterized molecules (2 quinones, 4 sesquiterpene lactones and 1 platinum complex). Restricting the analysis to the last group, the two quinones identified as hits were recently shown to have sub-µM EC 50 against T. cruzi amastigotes (compounds 9 and 14 in (Ballesteros-Casallas et al, 2023). All sesquiterpene lactones assayed displayed anti-T. cruzi activity (cell viability ≤61%) and the two most potent: helenalin acetate (2% viability) and budlein A (26% viability), have already been reported to be one-digit μM inhibitors of T. cruzi amastigotes (EC 50 = 6.93 μM and 1.75 μM, respectively; Schmidt et al, 2002;.…”