Japanese researchers synthesized menthol esters, which showed anti-inflammatory and anti-obesity activities.
- Researchers at Tokyo University of Science synthesized new menthol amino acid derivatives, menthyl esters of valine and isoleucine, and studied their properties.
- Thanks to these compounds, 18 genes involved in inflammatory and immune responses were suppressed.
- Furthermore, mentethyl esters inhibited adipogenesis and fat accumulation in mice.
Obesity and inflammatory diseases are increasingly prevalent and increase the risk of diabetes and hypertension. In a recent study, scientists from the Tokyo University of Science (Japan) looked at the effectiveness of menthol amino acid derivatives. As a reminder, it is a natural cyclic monoterpene alcohol that is found in various plants and which gives mint its refreshing properties. The latter is known for its analgesic and anti-inflammatory effects.
Menthyl esters outperformed menthol in anti-inflammatory test
As part of their research, the team focused on the menthyl esters of valine and isoleucine. She began by synthesizing menthyl esters of six amino acids “characterized by less reactive side chains”. The researchers then evaluated the properties of these esters using in vitro studies on cell lines. Finally, they conducted experiments on mice to explore the effects of these compounds under pathological conditions. To determine the anti-inflammatory effects of mentethyl esters, the authors evaluated “tumor necrosis factor-α (Tnf) transcript levels in stimulated macrophage cells.”
According to the results, published in the journal Immunology, menthyl esters of valine and isoleucine showed greater anti-inflammatory activity than menthol. RNA sequencing analysis revealed that 18 genes involved in inflammatory and immune responses were deleted. By examining the mechanism of action of menthyl esters, scientists discovered that the liver X receptor (LXR), an intracellular nuclear receptor, plays an important role in anti-inflammatory effects. “Unlike menthol, which acts primarily through the cold-sensitive TRPM8 channel, these menthyl esters exhibit unique mechanisms that operate independently of this receptor,” do they have explain.
Obesity: Menthyl esters suppressed adipogenesis in mice
Another observation: the Scd1 gene, which plays a central role in lipid metabolism, was upregulated by the liver X receptor. Furthermore, the team observed that menthyl esters showed remarkable effectiveness in suppressing adipogenesis and fat accumulation. In animal trials, diet-induced obesity in mice was ameliorated and adipogenesis was suppressed.
“These multiple capabilities of our compounds make them formidable allies in the fight against inflammation and obesity, opening the way to a whole series of potential therapeutic applications,” can we read in the conclusions of the work.
