There are a lot of issues with this study, but I'll start with the obvious one: They exposed those stem cells to a concentration of 15μM luteolin. That's gros

There are a lot of issues with this study, but I'll start with the obvious one: They exposed those stem cells to a concentration of 15μM luteolin. That's grossly non-physiological. There's no way that you're ever going to see a 15µm plasma concentration following luteolin supplementation, at any reasonable dose. What's more: "Luteolin exhibits limited blood-brain barrier permeability (−0.907) and CNS permeability (−2.251), indicating poor penetration into the brain." > https://www.sciencedirect.com/science/article/pii/S2225411024000555 https://www.sciencedirect.com/science/article/pii/S222541102... So if 15µm concentrations are unattainable in plasma, the brain would be exposed to much less still. In animal experiments, as noted in your link, luteolin appears beneficial. There could be a dose-response-curve thing, where reasonable (physiological) amounts are neuroprotective, whereas exposing cells to very high concentrations directly is damaging.