Extended Data Fig. 6: Evaluation of ferroptosis inhibition potency for competing RTAs (resveratrol, left; PMHC, center; phenoxazine, right).
Each of these antioxidants may be ranked based on their autooxidation inhibitory effect as, respectively: weaker than, as strong as, and stronger than H4B-PMHC. Lipid peroxyl radical measured by H4B-PMHC fluorescence (10 nM, top). Membrane integrity assessed by PI fluorescence (1 µM, bottom). For each condition, the competing RTA was added together with H4B-PMHC and incubated for 10 minutes. Imaging was initiated immediately after RSL3 addition (1 μM). For control groups (basal conditions, grey), only H4B-PMHC were added (no competing RTA or RSL3) but conducted under otherwise similar conditions. Bars = SEM, n = 4 (replicates across independent wells). Imaging studies with phenoxazine, an RTA with superior scavenging activity than α-tocopherol (and thus H4B-PMHC), showed suppression of fluorescence enhancement. In turn, imaging with PMHC, which has a comparable RTA activity to H4B-PMHC, displayed a flattening of the runaway period in a concentration dependent manner. Imaging with resveratrol, a case study for a poor RTA, lead to no changes in the induction period, indicating that H4B-PMHC outcompeted resveratrol as an RTA.
