LIQUORICE DRUG BOOSTS MEMORY IN ELDERLY

A compound based on a liquorice extract improves memory in older men, shows a new study.

The substance works by blocking the activity of a brain enzyme that boosts levels of the stress hormone cortisol. This hormone is thought to be responsible for eroding memory with age.

The drug, called carbenoxolone, was once used to treat stomach ulcers. But when given to men aged between 55 and 75 it sharpened their verbal memories within weeks.

"You get subtle but definite improvements," says Jonathan Seckl who led the study at the University of Edinburgh, Scotland. Verbal memory, he explains, is needed for remembering recently received information, and is "crucial to normal functioning" - for example, recalling the time of an appointment.

Seckl believes such compounds may be available for the elderly within five years to help improve memory and possibly even treat dementia. "A lot of fine ideas get stuck between animal models and the first clinical trial, but we have at least got preliminary [human] data suggesting it would be a good idea," he told New Scientist.

The age profile of the developed world's population is rapidly becoming older, meaning that more and more people will suffer memory problems. A spokesman for UK charity Age Concern welcomed the new research and called for further research into the possibilities it has uncovered.

'Wear and tear'

Seckl says age-related memory decline is common even in healthy older people. About 10 per cent of people in their 70s have severe problems, but 25 per cent "just don't remember things as well".

One strong theory to explain this kind of age-related decline is that the stress hormone cortisol causes "wear and tear" in the brain over a lifetime of exposure.

High levels of stress hormones particularly damage the hippocampus - the brain's centre for learning and memory - which has more receptors for cortisol than other parts of the brain.

"It doesn't knock the neurons out, it just rips out some of the wiring - the interconnections between the brain cells," Seckl explains. Carbenoxolone acts by blocking an enzyme that converts an inactive form of the stress hormone to an active one in the brain.

Side-effects

In the trial, 10 healthy older men were given carbenoxolone three times a day for four weeks. This improved their verbal memory compared with when they were given a placebo.

In 12 older men with type 2 diabetes, a disease that can cause subtle impairment of memory, it improved verbal memory skills after six weeks on the same dose.

However, eating liquorice will not boost brainpower cautions Seckl, as the active component of carbenoxolone is modified to help it enter cells more easily than the natural substance.

Also, the active component can have serious side-effects as it can cause high blood pressure. In this study, funded by the Wellcome Trust, the team gave another drug alongside carbenoxolone to reduce this adverse effect.

Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0306996101)

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