A widely-used health supplement could help protect the brain against the effects of a stroke.

Scientists found that ginkgo reduced stroke damage in mice by 50 per cent, with less paralysis and limb weakness.

Ginkgo biloba is a tree native to China with fan-like leaves. Supplements containing the plant are widely available from health food shops and chemists and used to enhance memory and concentration.

Study leader Dr Sylvain Dore, from Johns Hopkins Institutions in Baltimore, Maryland, US, said: "Our results suggest that some element or elements in ginkgo actually protect brain cells during stroke.

"If further work confirms what we've seen, we could theoretically recommend a daily regimen of ginkgo to people at high risk of stroke as a preventive measure against brain damage."

Dr Dore added: "It's still a large leap from rodent brains to human brains but these result strongly suggest that further research into the protective effects of ginkgo is warranted."

The findings were published in the journal Stroke.