Super Mint to Counter Joint Inflammation

Mint is a common natural source of Rosmarinic Acid (RA), a chemical compound that has antioxidant and anti-inflammatory properties.

When some research horses at the University of Guelph in Ontario, Canada, escaped from their paddock one spring night, they happened upon a research plot of mint being grown by the University’s Department of Plant Agriculture.

The horses were safely returned to their pasture, but the hoof prints and poop piles they left amongst the rows of mint suggested they were quite interested in this particular crop – as were the University’s researchers.

It’s the same species of spearmint you’d find at home in your herb garden, but this particular strain has a decade of research and development behind it. Today, all that work appears to have been worth it: this mint is showing promising results as a supplement to treat joint inflammation in horses.

ELUSIVE HIGH LEVELS

Mint is a common natural source of Rosmarinic Acid (RA), a chemical compound that has antioxidant and anti-inflammatory properties. Among mint varieties in the wild, levels of the substance can vary greatly from plant to plant. Of 1000 plants, perhaps only two or three have high levels of RA.

Through a careful process of screening and selection, research scientists at Guelph managed to isolate a genetic strain of the mint that naturally and consistently overproduces the medicinal compound. “What we have is a spearmint plant that is essentially identical to the wild type, except it produces 20 times higher levels of Rosmarinic Acid” explains Laima Kott, PhD, the lead researcher of the project.

The mint is not genetically modified and is easily grown. The high levels of RA also mean less of the dried plant matter is required to deliver the potential beneficial effects. “You can just grow it in a field,” says Kott, “rather than trying to make a complex molecule like Rosmarinic Acid in the lab, which is difficult and expensive to do.”

VALUABLE RESEARCH

University of Guelph graduate Wendy Pearson, PhD, helped secure research money to study the effects of the mint in horses. With horses of her own at home, and having studied veterinary applications of medicinal plants in her PhD work, Pearson is keenly aware of the value of this sort of research to the equine industry. “ Arthritis is a common cause of lameness in horses,” Pearson explains, “and there are many well-known adverse effects from the more conventional types of drugs we use to treat it. So there’s a real place for the development of new natural products like this that can help mitigate some of the symptoms, but hopefully with fewer adverse effects.”

The first stage in the research study involved looking at the effect of the mint on cultured samples of cartilage tissue in vitro (not in a live animal). The cartilage was subjected to chemicals that cause it to behave arthritically and the effects of the mint were measured. “The results were extremely good - to the extent that none of us could really believe what we were looking at,” says Pearson of the study that was published in the BMC Journal of Complementary and Alternative Medicine. “There was almost a complete inhibition of PGE2, one of the chemicals you are trying to block when you take aspirin or feed your horse bute. We also saw a protective effect on cartilage structures; when we pretreated the cartilage with mint, it didn’t break down nearly as quickly.”

The next step was to see what the mint could do in a live animal. Eight horses with experimentally induced low-grade inflammation in their knee joints were fed a controlled diet with half the horses receiving dried mint leaves mixed with their grain. “We looked at a lot of the same outcome measures that we looked at in the in vitro model and we found that when the horses received the mint as part of their normal diet the inflammatory changes in the biochemistry of the joint were strongly inhibited,” says Pearson.

She believes the results are significant. “There’s a lot of misconceptions out there, that herbal stuff is just snake oil, but in reality, where do many of our drugs come from? According to the World Health Organization bulletin, 80% of the world’s medicines are derived from plants. In North America, 25% of all of the drugs you get at pharmacies come directly from plants. So it really does make sense that you would have this type of bioactivity, and it’s really nice to be able to measure that in a study like this.”

Pearson admits the mint is not going to provide a cure for osteoarthritis, but believes it does provide another level of support we might not be getting with conventional drugs alone. Plans are underway for a clinical trial with people suffering from knee osteoarthritis (patients will drink herbal mint tea). Pearson would also like to see a clinical trial with horses, and maybe dogs, who could also benefit from the treatment.

So would feeding regular mint benefit your horse? Pearson doesn’t think so. “We tested a regular mint in the in vitro experiment, and we didn’t see any effect.”

The good news? The high RA mint is now being incorporated into a number of herbal products produced by Herbs for Horses, a Guelph, Ontario based manufacturer of equine supplements.

Lindsay Day is a Registered Equine Massage Therapist and award-winning journalist dedicated to improving the health and welfare of horses through her work. www.EQmassage.ca

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