The kitchen herb sage can improve memory, finds new research which could have significant implications for treatments for Alzheimer's disease, suggest the UK-based researchers.
The team, from the Medicinal Plant Research Centre (MPRC) at the Universities of Newcastle and Northumbria, UK, report that healthy, young adults who took sage oil capsules performed significantly better in a word recall test than those who took placebo pills.
It is known that people took sage for memory loss centuries ago and drank teas and tinctures containing extracts of the herb. The new results back texts by well-known herbalists such as John Gerard, who wrote in 1597 that sage "is singularly good for the head and brain and quickeneth the nerves and memory".
The new study, published in the current edition of the journal Pharmacology, Biochemistry and Behaviour, tested 44 healthy young adults aged between 18 and 37. Some were given capsules containing sage oil, provided by Oxford Natural Products, and others were given placebos.
The volunteers then took part in a word recall test and tested at intervals to see how many words they could remember. Results showed that those who had taken the sage oil consistently performed better than those who had taken placebos.
Sage is currently being investigated as a potential treatment for Alzheimer's disease after earlier research by the MPRC found that it inhibits an enzyme called acetylcholinesterase (AChE), which breaks down the chemical messenger acetylcholine. Alzheimers', the most common form of dementia which affects an estimated 10 million people worldwide, is accompanied by a drop in acetylcholine.
Many of the current drugs, such as donepezil, have unpleasant side effects and doctors are keen to find alternatives. No side effects were noted in the sage trial.
Further investigation is needed to find out why sage is so effective but researchers think it could be a combination of chemicals in the oil which have an effect on AChE and which give it antioxidant, oestrogenic and anti-inflammatory properties, also considered to be of value in Alzheimer's therapy.
Lead researcher Nicola Tildesley said: "This research has serious implications for people suffering from Alzheimer's disease, as it will inform drug research and development. This proves how valuable the work by the old herbalists is, and that they shouldn't just be ignored because they were writing centuries ago."
The MPRC is currently carrying out another clinical trial testing the effects of sage on people with Alzheimer's.