Scientists hope the naturally-occurring extract quercetin will pave the way for new treatments to ease the symptoms of incurable spinal muscular atrophy (SMA).
The disease leaves children with little or no control of their movements and is a leading genetic cause of death in infants and toddlers.
One in 6000 babies are affected by the condition, sometimes referred to as childhood form of motor neuron disease, and around half of those with the most severe form will die before the age of two.
A team from Edinburgh University found evidence that quercetin - present in some fruits, vegetables, herbs and grains - could help prevent damage to nerves associated with SMA.
The chemical targets the build-up of a specific molecule inside cells, that is responsible for some of the symptoms of the condition.
Tests of a purified form of the extract on zebrafish, flies and mice led to a significant improvement in the health of nerve and muscle cells.
Professor Tom Gillingwater, who led the study, said: "This is an important step that could one day improve quality of life for the babies affected by this condition.
"There is currently no cure for this kind of neuromuscular disorder so new treatments that can tackle the progression of disease are urgently needed."
Quercetin did not prevent all of the symptoms, but researchers hope that it could offer a useful treatment option in the early stages of disease.
They hope to create better versions of the chemical that are more effective than naturally-occurring quercetin.