A recent rat model of glaucoma found that a proprietary spearmint extract supports oxidative stress and inflammation in eye neural tissue

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A recent animal study¹ investigated the effects of a proprietary spearmint extract (Neumentix from Des Moines, IA-based Kemin Industries) on retinal ganglion cell density, activity, and neuronal health markers in a rat model of hypertensive glaucoma. The researchers explain that glaucoma is characterized by a loss of retinal ganglion cells, and while it’s well known that intraocular pressure is elevated in glaucoma, another promising target for managing the disease is oxidative stress and inflammation.

In the study, animals were divided into four groups: an untreated healthy control, and three glaucomatous groups receiving either an orally administered vehicle, a low dose of the spearmint extract, and a high dose of the spearmint extract for 28 days. Researchers observed a dose-dependent response from the spearmint extract, significantly preserving the density of retinal ganglion cells to the point where retinal ganglion cell density in the high-dose group was not statistically different from healthy controls.

The spearmint extract also promoted neural trophism as measured by the protein levels of the crucial neutrophins, brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), which significantly increased in a dose-dependent manner. The researchers explain that the levels of neutrophins, BDNF, and NGF are known to promote neuronal survival and synaptic plasticity in the central nervous system. Analysis of oxidative stress and inflammation showed that the spearmint extract had a dose-dependent impact on the inhibition of oxidative stress as well as pro-inflammatory cytokines, and an increase in anti-inflammatory cytokines.

“The research substantiates the role of oxidative stress, inflammation and neurotrophin support in driving neurodegeneration in retinal ganglion cells, but also demonstrates the potential to counteract these drivers with nutritional strategies,” said Massimo Dal Monte, the principal investigator of the study, and professor at the University of Pisa, in a press release.

“Our findings emphasized the intraocular pressure (IOP)-independent antioxidant and neuroprotective effects of Neumentix,” added Rosario Amato, PhD, post-doctoral research fellow from the University of Pisa. “Glaucoma provides a model of neurodegeneration and is understood as a multifactorial condition influenced by mechanisms such as high oxidative stress, inflammation and lack of neural trophic support. In our results, we observed that this spearmint extract dose dependently modulates neuroprotective mechanisms, relevant for the management of glaucoma, which act downstream from the IOP elevation.”

According to Kemin Industries, Neumentix is sourced from patented plants and characterized by its phenolic complex. “Several of the most prominent age-related changes in the human body are brain and vision related,” said Samanta Maci, Senior Commercial and Technical Manager, Kemin Human Nutrition & Health, in a press release. “Damage to the neural tissue in the retina leads to a host of well-known dysfunctions, which are not only confined to the eye, but spread along the entire visual pathway. These findings complement the research already conducted on cognitive health in healthy subjects. They further support the use of Neumentix as a nutritional support in neural health and establish Neumentix as the right ingredient to innovate this field.”

Reference

Amato, R.; Canovai, A.; Melecchi, A.; Maci, S.; Quinetela, D.; Fonseca, B.A.; Cammalleri, M.; Monte, M.D. Efficacy of a spearmint (Mentha spicata L.) extract as nutritional support in a rat model of hypertensive glaucoma. Tsvt, 2023, 12 (11). DOI: 10.1167/tvst.12.11.6