Ginkgo biloba extract has long been used as a traditional herbal treatment in China for a range of conditions, including depression, memory loss, and confusion, and is widely available as a food supplement.
Therefore, researchers at Nanjing University Medical School wanted to see if it might help lessen or halt the cognitive decline associated with the aftermath of a blood clot in the brain (ischaemic stroke).
They randomly assigned 348 people to daily treatment with either 450 mg of ginkgo biloba extract, given in three doses, plus 100mg of aspirin, or 100mg of aspirin alone for six months.
Everyone started their treatment within seven days of being admitted to one of five different hospitals after having had an ischaemic stroke. Their average age was 64.
The ginkgo biloba used contained more protective and fewer harmful chemicals than the extract, which has typically been used in previous studies, said the researchers.
The study participants took a validated neuropsychological test (Montreal Cognitive Assessment score or MoCA) at the start of the trial, and then 12, 30, 90 and 180 days later to check for any cognitive impairment, including a decline in executive function.
A lower MoCA score, which ranges from 0 to 30, indicates a greater degree of cognitive impairment.
Eighteen patients dropped out of the trial, so the final analysis was based on 330 people.
The test results at 12, 30, 90 and 180 days showed that those given the combination treatment had higher scores for cognitive skills, including memory and executive function, than those given aspirin alone.
They also had a greater degree of functional capacity 12 and 30 days after the start of treatment, indicating a greater improvement in neurological deficit, such as muscle weakness, impaired reflexes and speech problems, following their stroke.
During the six-month trial, few side effects were reported, indicating that ginkgo biloba plus aspirin was safe.
The vascular health of the trial participants was subsequently monitored for nearly two years, and there was little difference between the two groups.
The researchers concluded: "GBE in combination with aspirin treatment alleviated cognitive and neurological deficits after acute ischaemic stroke without increasing the incidence of vascular events."
However, they conceded that the monitoring period was not very long, and that both the clinicians and the patients knew which treatment they had been assigned to, which may have skewed the results.
Further longer terms studies looking at stroke severity would be needed, before any more definitive conclusions could be reached, they added.
Source: Stroke & Vascular Neurology
"Ginkgo biloba extract improved cognitive and neurological functions of acute ischaemic stroke: a randomised controlled trial"
Authors: Shanshan Li, et al