Chronic inflammation often develops silently, without obvious pain or noticeable symptoms. But over time, it can lead to serious health problems such as type 2 diabetes, heart disease, obesity, arthritis, and even cancer. In the body, this process is driven by immune cells that release chemical signals to respond to injury or infection. What people eat can affect this activity. Many common foods and seasonings, such as herbs, spices, and aromatic plants, contain natural compounds known as phytochemicals that can influence inflammatory pathways. These ingredients have been combined in traditional diets and herbal remedies for centuries, long before their biological role was understood.
Despite this long history, researchers have struggled to explain exactly how plant-based foods reduce inflammation. In laboratory settings, individual plant compounds often exhibit anti-inflammatory effects, but usually only at levels much higher than those obtained in a normal diet. This has led to questions about whether so-called “anti-inflammatory foods” can really impact the immune system in real life. Another unresolved question is whether different compounds work together in cells and produce more powerful effects in combination than alone. Until recently, this type of synergy has rarely been tested or described at the molecular level.
Research investigating how plant compounds work together
To better understand this, a team led by Professor Genichiro Arimura of the Department of Physics and Engineering at the Tokyo University of Science in Japan investigated how combinations of plant-derived compounds affect inflammation in immune cells. Their findings were published in Volume 18, Issue 3 of the journal. nutrientsfocused on compounds commonly found in mint, eucalyptus, and chili peppers. The researchers wanted to see if using these compounds in combination could reduce inflammatory signals more effectively than using them individually.
Testing of anti-inflammatory effects on immune cells
The researchers studied macrophages, immune cells that play a key role in inflammation by releasing signaling proteins called cytokines. These proteins help promote an inflammatory response. To simulate inflammation, the researchers exposed mouse macrophages to lipopolysaccharide, a bacterial component commonly used in laboratory experiments. They then treated the cells with menthol (from mint), 1,8-cineole (from eucalyptus), capsaicin (from chili peppers), and beta-eudesmol (from hops and ginger), testing each compound alone or in specific combinations.
The scientists used gene expression analysis, protein measurements, and calcium imaging to track how these treatments affected key inflammatory markers. They also investigated whether these compounds act through transient receptor potential (TRP) channels, proteins in cell membranes that detect chemical and physical signals and regulate calcium activity associated with immune responses.
Strong synergy between common food compounds
When tested individually, capsaicin showed the strongest anti-inflammatory effect. However, the most striking results appeared when the compounds were combined. “Using capsaicin and menthol or 1,8-cineole together increased the anti-inflammatory effect hundreds of times compared to using each compound alone,” emphasizes Professor Arimura.
Further experiments helped clarify how this synergy works. Menthol and 1,8-cineole influenced inflammation through TRP channels and calcium signaling. Capsaicin, on the other hand, appears to act through a different pathway that is independent of TRP channels. “We have demonstrated that this synergistic effect is not coincidental, but is based on a novel mechanism of action resulting from the simultaneous activation of different intracellular signaling pathways,” says Professor Arimura. “This provides clear molecular-level evidence for the effects of empirically known combinations of food components.”
What this means for diets and future health products
These results suggest that mixtures of plant compounds can produce meaningful biological effects even at the low levels typically consumed in the normal diet. The findings also present new opportunities to develop functional foods, nutraceuticals, seasonings, and even fragrances that use smaller amounts of active ingredients to deliver more powerful effects.
More broadly, this study supports the idea that the health benefits of plant-rich diets may come not from individual “super compounds,” but from the way many compounds interact and enhance each other.
A step towards understanding food and inflammation
Although additional studies in animals and humans are needed to confirm these effects, this study provides a clearer explanation of how everyday foods and natural compounds can help regulate chronic inflammation. Over time, this can play an important role in supporting long-term health.
About Professor Genichiro Arimura of Tokyo University of Science
Dr. Genichiro Arimura is a professor at the Faculty of Biological Science and Technology, Tokyo University of Science. Professor Arimura received his Ph.D. Completed doctoral course at Hiroshima University Graduate School in 1998. His research focuses on biological communication, plant biotechnology, and plant ecology. Since 1996, he has published 130 peer-reviewed papers with over 6,600 citations. He also holds four patents and received an award from the International Society of Chemical Ecology in 2023.
Funding information
Part of this research was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (24K01723) and the Tokyo University of Science Research Grant.
