New Rosy Immunomodulator in Rose Discovered

Highlights:

Dendritic cells are an integral part of immunology, although they can cause inflammatory and autoimmune diseases
Autoimmune disease happens when the body's natural defense system can't tell the difference between your own cells and foreign cells, causing the body to mistakenly attack normal cells
A recent study shows that a potent immunomodulator called β-damascone is present in roses which can be used as potential treatment in the future

Dendritic cells (DCs) are one of the most important players of the immune system. They perform important functions such as the identification of infectious pathogens, production of cytokines, which are the chemical signalers of the immune system, presentation of antigens to activate T-cells.

Just like what is good for us can also be equally harmful for us, DCs may lead to inflammatory and autoimmune diseases when hyperactive. Identifying natural compounds that can regulate DC-mediated functions is imperative.

A recent study screened 150 natural aroma compounds. They discovered that β-damascone, a major aroma component of rose, can suppress DC-mediated immune functions. In vivo experiments in mice models demonstrated that β-damascone has anti-inflammatory properties and can be promising as an effective immunomodulatory drug.

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‘An aroma component present in rose gives hope for those with autoimmune disorders’

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Nature may have the Answers

Previous research has indicated that natural compounds can serve as potent immunomodulators. To explore the role of such compounds in modulating the functions of DCs, a team of researchers from Japan, led by Prof. Chiharu Nishiyama from Tokyo University of Science, including Dr. Hikaru Okada, Dr. Masakazu Hachisu, and Dr. Naoki Kodama, screened 150 types of natural aroma compounds. Natural fragrant compounds are found in plants and microorganisms and are also commonly used in foods and daily necessities. However, not much research has been conducted on the physiological activities of individual flavor compounds, particularly on immune responses ().

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Identifying β-damascone in Rose as an Immunomodulator

Turns out smelling roses is not just for Valentine’s Day. The team of researchers first conducted a two-step screening process of aroma compounds, which led to the identification of a novel and effective modulator of DCs known as β-damascone, which is a primary component that constitutes rose fragrance.

The next step was to perform a series of molecular and immunological assays. The team found out that β-damascone inhibited several functions of DCs including antigen-dependent activation of CD4+ T-cells and the development of Th1 cells (Type-1 helper cells). In addition, β-damascone reduced the production of inflammatory cytokines such as interleukin IL-6, IL-12p40, and tumor necrosis factor (TNF)-a.

Discussing these findings, Prof. Nishiyama further adds, “We wanted not only to observe the effective active ingredients, but also to thoroughly examine their mechanisms of action at the molecular level, up to the point of verifying whether they exert physiologically meaningful effects.” True to their word, on exploring the mechanisms underlying the inhibitory functions of β-damascone, the team noted that these functions were mediated by NRF2, which is a master transcription factor with crucial antioxidative roles. NRF2 was found to exert these effects via its target genes, Hmox1 and Nqo1.

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Effect of β-damascone on Inflammation

The function of β-damascone was further confirmed by in vivo experiments in contact hypersensitivity mice models. The oral administration of β-damascone reduced ear inflammation in these mice models. Notably, these experiments also corroborated the role of NRF2 in β-damascone-mediated immunomodulation. Indeed, ear swelling was not suppressed in NRF2 knockout mice models, i.e., mice that lacked NRF2.

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Future may be Looking Rosy for Those with Autoimmune Diseases

Taken together, this comprehensive study showed that β-damascone can function as an efficient modulator of DC-mediated functions and can effectively reduce the inflammatory effects of DC-hyperactivation.

The researchers are confident that these findings will lead to the application of β-damascone as a safe and effective immunomodulatory drug in the future.

Reference:

Rose flavor compound β-damascone regulates dendritic cell-mediated immunoresponses by modulating the NRF2 pathway and ameliorates contact hypersensitivity - (https://www.biorxiv.org/content/10.1101/2022.02.08.479651v1)

Source-Medindia