Spearmint Extract Neumentix May Outperform Standard Rosmarinic Acid as Anti-Inflammatory

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Scientists recently conducted an animal study comparing the potential anti-inflammatory effects of a polyphenol-rich spearmint extract containing rosmarinic acid to a standard rosmarinic acid extract. The study, which was published in The FASEB Journal¹ and supported by Kemin Industries Inc., found that Kemin’s proprietary Neumentix spearmint extract, which contains more than 50 phenolic compounds, including rosmarinic acid, was more effective than rosmarinic acid alone in attenuating inflammation.

Four groups of rats received intraperitoneal administration of either 1) Neumentix spearmint extract containing 15% rosmarinic acid at doses of 10, 30, or 100 mg/kg, 2) standard rosmarinic acid at doses of 15 or 50 mg/kg, 3) Indomethacin, an anti-inflammatory agent, at 10 mg/kg, or 4) saline as a control. Subplantar injections of carrageenan were then administered to induce paw edema (swelling) in all animals, with the exception of four animals in the control group, who received a saline injection. Using the volume displacement method, researchers measured paw volumes immediately following carrageenan injection and again at three and six hours later.

In the control group (animals given the saline control dose and then injected with carrageenan), paw volume increased by 36% and 46% at three and six hours, respectively, and was significantly higher than in the four subjects given the saline control dose and injected with saline at the same time points. The animals treated with spearmint extract, however, demonstrated less inflammation, with paw volume increases of 9%, 11%, and -8% at six hours post-injection for the 10, 30, and 100 mg/kg spearmint groups, respectively. Animals treated with 100 mg/kg spearmint extract at three hours experienced significantly lower paw volume increases than did the animals in the saline-carrageenan group at three hours.

Meanwhile, animals treated with 15 and 50 mg/kg standard rosmarinic acid showed increased paw volumes that were also significantly lower than the saline-carrageenan group at 3 and 6 hours, but not quite as low as those for the spearmint extract group. Compared to the saline-carrageenan group, animals treated with the anti-inflammatory agent experienced limited increases in paw volume.

Given that the spearmint ingredient outperformed standard rosmarinic acid, the study authors concluded that rich complex of polyphenol actives found in spearmint extract (beyond just rosmarinic acid alone) act synergistically and likely have an effect on the inflammation response.

References:

1. Fonseca B et al. “Anti-inflammatory effects of a polyphenol-rich spearmint extract in a rat paw edema model.” The FASEB Journal, vol. 31, no. 1 (April 2017).