Resveratrol, a compound produced in the skins of grapes, has long been touted as an elixir capable of combating many diseases from cancer to dementia.
But scientists have always struggled to translate these findings into successful treatments.
That is largely because the exact mechanism driving resveratrol’s effects have been poorly understood. Now experts at King’s College London say they have established how it works.
The researchers, funded by the British Heart Foundation, showed that resveratrol interacts with a protein called PKG1a in the wall of blood vessels. Resveratrol adds oxygen to the protein, causing the blood vessels to relax and expand, quickly leading to a drop in blood pressure.
This is a huge shift in the way scientists thought resveratrol worked. Many assumed it is an “antioxidant” - a substance that stops oxygen damaging cells in the body.
But in fact it does the opposite, allowing oxygen in the blood stream to interact and oxidise the PKG1a protein.
Writing in the Circulation medical journal, the scientists described how tests on cells taken from people’s blood vessels showed notable change.
They also gave a dose of resveratrol to mice, which resulted in a drop in blood pressure of 20mmHg, a substantial shift, in just 15 days.
The scientists said no blood pressure medications work in this way, paving the way for an entirely new class of drugs.
But they stressed that for a human to consume the same doses of resveratrol used in the study, they would need to drink around 1 000 bottles of red wine a day.
Resveratrol does not dissolve well and is broken down by the body before it can reach its target in the blood vessel wall. So drug developments will rely on altering the chemical structure of resveratrol to make it more resistant to breakdown, to ensure more of the compound reaches the target cells.
Study leader Dr Joseph Burgoyne at King’s said: “We’re slowly realising that oxidants aren’t always the villain.
“Our research shows that a molecule once deemed an antioxidant exerts its beneficial effects through oxidation.
“We think that many other so-called ‘antioxidants’ might also work in this way.
“Our work could lay the foundations for chemically altering resveratrol to improve its delivery to the body, or designing new, more potent drugs which use the same pathway. In the future, we could have a whole new class of blood pressure drugs.”
Professor Metin Avkiran at the British Heart Foundation added: “Unfortunately, this isn’t the all-clear to open a bottle of merlot.
“To get the human equivalent dose of resveratrol used here, you’d need to drink an impossible amount of red wine. This study reveals the surprising way in which resveratrol works and opens up the possibility of new blood pressure drugs which work in a similar way.