Blueberry compound fights cholesterol, study finds

A compound used by blueberries and grapes to fight off fungal infections could help lower cholesterol, US researchers have reported.

The compound, called pterostilbene, also helps regulate blood sugar and might help fight type II diabetes, the researchers told a meeting of the American Chemical Society in Philadelphia.

The finding adds to a growing list of reasons to eat colourful fruit, especially blueberries, which are rich in compounds known as antioxidants. These molecules battle cell and DNA damage involved in cancer, heart disease, diabetes and perhaps also brain degeneration.

"We are excited to learn that blueberries, which are already known to be rich in healthy compounds, may also be a potent weapon in the battle against obesity and heart disease, which are leading killers in the US," said Agnes Rimando of the US Department of Agriculture in Oxford, Mississippi.

Rimando's team had previously found pterostilbene in grapes. It is similar to a better-known antioxidant in grapes -- resveratrol.

They studied pterostilbene in rat liver cells, soaking them in four compounds found in blueberries including pterostilbene and resveratrol. Pterostilbene was the best at activating the PPAR-alpha receptor, a protein involved in lowering cholesterol and other blood fats.

In fact, they told the meeting, pterostilbene worked as well as the commercial drug ciprofibrate -- but it worked more accurately. It was so specific that it could have fewer side-effects than the drug, they said.

Pterostilbene and resveratrol are related chemicals belonging to a group of compounds called phytoalexins. Plants produce them in response to stresses such as fungal infection and ultraviolet light. Pterostilbene may also be a promising compound to develop into a natural-based fungicide, Rimando said.