Friday April 14 5:37 AM ET
By Patricia Reaney
LONDON (Reuters) - Single doses of the ancient herbal remedies ginkgo biloba and ginseng can speed up reaction time and improve memory and concentration, British researchers said on Friday.
Both herbs have been used for centuries and are among the most popular herbal remedies sold today. New research presented at the British Psychological Society conference in Winchester, southern England, showed just one dose can have an quick effect.
"There have been studies in the past which have shown that if you give people a one-off dose of gingko it improves cognitive performance," Dr Andrew Scholey told Reuters.
"What we found is that it speeded attention. So tasks requiring sustained attention were improved by gingko."
Ginseng has been claimed to have a variety of benefits, from relieving stress to acting as an aphrodisiac. But Scholey, a psychopharmacologist at the University of Northumbria, and his colleagues found it also improved memory.
"The gingko speeded attention, whereas the ginseng seems to improve memory, the storage and retention of information and the ability to concentrate," Scholey said in a telephone interview.
"As far as we know it is the first demonstration of an effect of a one-off dose of ginseng."
The researchers compared the effects of the herbal extracts on volunteers who were given one of three doses of the herbs or a placebo, or dummy pill. None of the volunteers or the researchers knew what each participant was given.
The volunteers were tested once a week over four weeks with seven days between each dose so their bodies would be clear of the previous dose. During the test day they were subjected to a battery of computerized tests to measure their speed and accuracy of attention and long and short-term memory.
"The most effective dose was 360 mg of ginkgo, the standard dose," said Scholey. "When people were given gingko at 9 o'clock in the morning their reaction times were still faster at 3 o'clock in the afternoon."
The experiments with ginseng showed a single 400 mg dose improved ability to store, hold and retrieve information.
Scholey, whose research was sponsored by Pharmaton Natural Health Products, said it is not known what effects sustained use of the herbal remedies would have.
"In some countries ginkgo is already the treatment of choice for Alzheimer's
disease," he said. "These results suggest that such extracts may have many
other medical applications such as helping people recover from local anesthetics."