Fig. 6: The combination of DHA and idelalisib led to more mitochondrial membrane potential loss and more DNA fragmentation.

Tightly synchronized ring-stage P. falciparum 3D7 cultures were exposed to 0.1% DMSO (control), DHA at the IC₅₀, idelalisib at the IC₅₀ or the combination of DHA and idelalisib (each at the corresponding IC₅₀) for 24 h until the parasites reached the late-trophozoite stage. After incubation, the parasite pellets were collected. The degree of mitochondrial membrane potential depolarization was subsequently determined using a TMRE fluorescent probe assay (A) by measuring the optical density at 550 nm (excitation wavelength) and 575 nm (emission wavelength). DNA fragmentation was determined using a TUNEL kit (B–D). CytoFLEX flow cytometry was used to analyse and calculate the percentage of TUNEL-positive cells, which indicated the level of DNA fragmentation. The combination of DHA and idelalisib induced more DNA fragmentation in 3D7-PfKelch13^C580Y (D) than in 3D7-PfKelch13^WT (C). One-way ANOVA and LSD-T post hoc test comparisons between treatment groups were employed. The means (s.d.) are based on three replicates (A, B) or four replicates (C, D) (the data points are shown). ***p ≤ 0.001.