Olive Oil Compound Shows Potential as Treatment for Alzheimer's Disease

A component of extra virgin olive oil has been found to protect brain synapses from damage caused by the buildup of toxic soluble oligomers of amyloid-beta peptide (ADDLs) in patients with Alzheimer's disease (AD).

Most researchers now believe that soluble oligomers of amyloid-beta peptide, rather than insoluble fibrils, act as the primary neurotoxin in AD. This has lead to a search for compounds capable of altering the assembly state of these oligomers and that may have potential for AD therapeutics.

One of these compounds is oleocanthal, which may be extracted from extra virgin olive oil. It is responsible for the slightly peppery "bite" of extra virgin olive oil, the cold-pressed result of the first pressing of the olives. This oil is only 1% acid and is considered the finest and fruitiest of the olive oils and is therefore the most expensive. Oleocanthal is a tyrosol ester, and its chemical structure is related to oleuropein that is also found in olive oil.

Oleocanthal has been found to have antiinflammatory and antioxidant properties. Similar to classical NSAIDs (nonsteroidal antiinflammatory drugs), it is a nonselective inhibitor of cyclooxygenase (COX). It has been suggested that long-term consumption of small quantities of oleocanthal from olive oil may be responsible in part for the low incidence of heart disease associated with a Mediterranean diet.

Investigators at Northwestern University (Evanston, IL, USA) studied the direct effect of oleocanthal on ADDL structure and on the binding of ADDLs to synapses.

They reported in the October 15, 2009, online edition of the journal Toxicology and Applied Pharmacology that treatment with oleocanthal increased the apparent size of ADDLs and rendered them more accessible to antibody binding. Treated ADDLs were found to be less able to interact with and bind to synapses of cultured hippocampal neurons. The hippocampus, a part of the brain intimately involved in learning and memory, is one of the first areas affected by AD.

"Binding of ADDLs to nerve cell synapses is thought to be a crucial first step in the initiation of Alzheimer's disease. Oleocanthal alters ADDL structure in a way that deters their binding to synapses," said senior author Dr. William L. Klein, professor of neurobiology and physiology at Northwestern University.

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