A plant-derived chemical from a South American tree shows promise in protecting eye cells from oxygen-starvation damage, hinting it might help with brain injuries too.

A natural compound called Brosimine B helps retinal cells survive better at a very specific low dose, but hurts them if you give too much.

This compound helps eye cells fight stress for a few hours, but after a full day, it stops working—so it won’t help if the damage lasts too long.

This compound helps eye cells make more of a natural 'clean-up' enzyme that fights harmful chemicals, but only if given early after stress begins.

If you give too much of this compound, it starts killing eye cells instead of helping them—typical of many natural substances that have a narrow safe range.

When eye cells are starved of oxygen and sugar, their natural defense system weakens—but this compound can help restore part of it, at least in the first few hours.