Why do people who eat a lot of pomegranates tend to have a healthier heart? According to biomedical researchers based in Wales, UK, we might have an answer. The scientists report that punicalagin, an antioxidant that gives pomegranates their rich red hue, seems to have powerful cardioprotective effects.
But here’s the kicker: many of us won’t get much benefit from eating the fruit. It turns out that we can’t absorb this heart-healthy chemical directly from pomegranates. Luckily for us, the researchers say they’ve identified the key chemical players that could protect your heart – and they can be extracted and purified into a form we can digest.
In a study published in April 2026 in the scientific journal Antioxidants, investigators led by Professor Dipak P. Ramji PhD, professor of cardiovascular science at Cardiff University’s School of Biosciences, report that antioxidant subunits of punicalagin have a calming effect on the inflammatory processes that cause atherosclerotic plaques to form. These molecules may also have a protective role against heart attacks and strokes due to their ability to stabilize the fatty deposits that break away and block blood flow to the heart and brain.
Put Down the Pomegranates For Now
Should we all rush out and buy pomegranate? Ramji explained to MNB that the secondary metabolites in the fruit that his team are working on have low bioavailability. This means that our bodies find it very, very hard to absorb and use much of it.
According to Ramji, we can’t directly absorb punicalagin and its derivatives through our digestive system very well. Instead we rely on the bacteria living in our digestive system to break these antioxidants down into smaller, easier to consume molecules.
What’s more, the type of bug that digests punicalagin for us seems to be rather selective about its hosts. This means not everybody has the right combination of gut bacteria to get the benefit from pomegranates.
The good thing is that researchers like Ramji and his colleagues have discovered the specific derivatives of Punicalagin that pack the most punch. Urolithins. Our cells can take up and use urolithins, and luckily for us, these molecules can be extracted from fruit and purified. Right now researchers are developing them as nutraceuticals.
Pac Man and Pomegranates
So how could punicalagin derivatives, urolithins, help our hearts?
It’s all about inflammation. If you’ve ever heard of fat clogging up your arteries, you might be surprised to find out that the problem isn’t necessarily that there are some fatty acids hanging out getting in the way.
The real problem is that the Pac Man-like white blood cells – macrophages and monocytes our immune system uses to chomp up and dispose of cellular trash tend to freak out when they suck up too much fat. Their reaction to fat deposits in our arteries triggers an immune overreaction.
Stuck in turbo mode, these cells recruit other kinds of inflammatory cells that put the fat on blast, causing collateral damage to the walls of your blood vessels. Over time, the blood vessel walls develop scar tissue and scabs that contain a mix of fat, old white blood cells, platelets, etc. that can break off and stop up your arteries. All this inflammatory activity also makes our blood vessel walls thicker and more stiff – making your heart work harder to push your blood around.
Antioxidants are often praised for their role in protecting DNA and important enzymes from reactive oxygen species, but scientists have also discovered that they can modulate our inflammatory responses.
Cardioprotective properties Punicalagin/Urolithins
Ramji and his team, with Sulaiman Alalawi at the tip of the spear, used a variety of lab-based experiments involving tissue samples, cell culture and mouse models to figure out what cardioprotective properties punicalagin and urolithins have.
The team first established which derivatives of punicalagin have antioxidative effects in a test tube and on a variety of human cell samples. Then they went on to test how punicalagin and urolithins should affect the ability of monocytes to suck up fatty acids. They simply dissolved the punicalagin and urolithins and added them to human monocytes in a dish and introduced some lipid-based dye. The antioxidants significantly reduced the amount of dye the monocytes took in.
Next, they showed that adding punicalagin and urolithins A and C to a dish of monocytes crawling towards a target slowed them down dramatically. They also saw that these punicalagin and metabolite soaked monocytes passed on sucking up labelled fatty acids added to the mix that they would usually hurry to absorb. Testing the effects of punicalagin and its metabolites on macrophages and cultured aortic blood vessel cells, showed that adding these chemicals reduced markers of inflammation in response to cholesterol.
So in a test tube or a dish of disembodied cells, punicalagin and urolithins seemed pretty handy at calming those Pac Man like immune cells, but what about real life?
Atherosclerotic Mouse Models
The team fed laboratory mice a high fat diet to trigger atherosclerosis. They gave a subset of the mice urolithin A supplements mixed into their food. After a period of three months, they sacrificed the mice and took a look inside their arteries.
As they had hopes, the mice who ate urolithin A had fewer plaques. The ones they had were smaller and contained fewer white blood cells. The insides of the blood vessels near the plagues showed less stiffening and fewer blockages in mice who had never eaten urolithin A.
Finally, they surveyed at the blood lipid results of both sets of mice. Both had around the same lipid numbers. This means that the beneficial effect that urolithin A had on the mice was more likely to be on the immune response than because it somehow lowered their cholesterol levels.
Supplements Soon?
So all in all, what’s next for punicalagin and urolithin A?
Watch this space, maybe while you drink some pomegranate juice if you are lucky enough to have the right microbiome. As Rami says, ‘Our findings show that it’s not just what we eat, but how our gut bacteria process those foods that really matters for heart health.’
Source
Alalawi S, Rifqi D, Alhamadi A, et al. Anti-Atherogenic Actions of Pomegranate Polyphenol Punicalagin and Its Metabolites: In Vitro Effects on Vascular Cells and In Vivo Atheroprotection by Urolithin A via Anti-Inflammatory and Plaque-Stabilising Mechanisms. Antioxidants. 2026;15(4):507. doi:10.3390/antiox15040507
