Researchers find rosemary compounds that may restore memory, treat Alzheimer's

A research team from The Scripps Research Institute in the US has successfully developed extracts from commonly found herbs, rosemary and sage, which could lead to a new treatment approach for Alzheimer's. The compounds were found to improve memory and increase brain cell density in lab mice.

The study, published in the journal Antioxidants on February 28, 2025, explains that the team synthesized a more stable derivative of carnosic acid, found in rosemary and sage, called diAcCA, and administered it to genetically modified mice with Alzheimer's-like symptoms for three months.

Mice treated with the new drug showed improved learning and memory skills, along with an increase in synapse numbers. Synapses are the points where nerve cells communicate, and the loss of synapses is closely linked to cognitive decline.

Additionally, the mice treated with diAcCA showed reduced accumulation of harmful amyloid and tau proteins, which are key characteristics of Alzheimer's disease in humans.

Professor Stuart Lipton, one of the study's authors, said, "By combating inflammation and oxidative stress with diAcCA, we were able to actually increase the number of synapses in the brain. We also reduced the amount of misfolded or aggregated proteins, such as tau with phosphate and amyloid-beta, which are believed to cause Alzheimer's disease."

Carnosic acid is an antioxidant and anti-inflammatory compound but has a very short shelf life. In contrast, diAcCA can be taken orally before being converted into carnosic acid in the stomach and entering the bloodstream.

The blood levels of diAcCA in the mice were 20% higher than direct carnosic acid intake. Researchers found that the mice tolerated diAcCA well and not only slowed the decline but also almost returned to normal function.

Alzheimer's disease accounts for 70% of dementia cases and presents a significant and growing global burden due to the ageing population.