Asian spice shows strong antioxidant powers
a key enzyme that protects the brain against oxidation, thought to
be a major factor in ageing and responsible for neurodegenerative
disorders like Alzheimer's disease.
A laboratory study by an Italian and US team, being presented this week, demonstrates how the spice strongly induced expression of a gene that helps protect brain cells exposed to an oxidant challenge.
It provides further evidence of the spice's antioxidant effects, already shown to fight some cancers and autoimmune diseases, such as multiple sclerosis.
There is a growing need for remedies to fight the conditions associated with ageing, as elderly populations continue to expand around the globe. The number of people with dementia is steadily increasing and there are nearly 18 million people with the disease in the world. Alzheimer's disease is the most common form of dementia, making up 55 per cent of all cases.
The researchers from the University of Catania in Italy and New York Medical College based their study on one of the most prominent current theories of ageing, the 'free radical theory'. It is thought that damage by free radical molecules to key intracellular targets is a major cause of the degenerative diseases related to ageing such as cancer and Alzheimer's disease.
Mammalian cells have developed highly protective systems against oxidative challenges that when properly activated, can restore cells' resistance to oxidation. Activation of antioxidant pathways is particularly important for tissue with relatively weak antioxidant defenses, such as the brain.
There are a variety of genes encoding proteins that possess antioxidant properties, including the hemeoxygenase-1 (HO-1), which has been reported to operate as a fundamental defensive mechanism for neurons exposed to an oxidant challenge.
In a lab study, the US-Italian team found that curcumin strongly induced HO-1 expression and activity in rat astrocytes, cells that perform a variety of functions in the central nervous system, including support to neurons and cleaning up of debris within the brain.
Previous studies have shown that induction of HO-1 can represent an efficient antioxidant system and a potential pharmacological target in a variety of oxidant- and inflammatory-mediated diseases, including brain ageing and neurodegenerative disorders.
The new study extends previous findings examining the neuroprotective effects of curcumin and its ability to induce HO-1 on cultured hippocampal neurons. It also investigated the effects of curcumin on the expression profiles of other genes involved in the cellular stress response.
The research will be presented at the American Physiological Society's (APS) annual scientific conference, Experimental Biology 2003, being held 17-21 April at the Washington DC Convention Center.