Rice is the staple food in the Asian diet, accounting for nearly 90 percent of the world’s rice consumption. Brown rice is known to have several health benefits. As a supplement to your daily diet, it can aid in weight loss, lower cholesterol and curb inflammation. Brown rice’s ability to neutralize reactive oxygen species and prevent cellular damage is critical to its many health-promoting effects. Although previous research has shown that antioxidant compounds in brown rice protect cells from oxidative stress, knowledge of which major compounds contribute to these beneficial properties has long been a mystery.
In a recent study led by Professor Yoshimasa Nakamura of Okayama University’s Graduate School of Environmental and Life Sciences, researchers from Japan identified cyclic ferulate (CAF) as the main “cytoprotectant” or cytoprotective compound in brown rice. Due to its hybrid structure, CAF is a unique compound. As Professor Nakamura explained, “CAFs are hybrid compounds of polyphenols and phytosterols, which are expected to be potent bioactive substances with various pharmacological properties, such as antioxidant effects and hypolipidemic effects.“
This study was published in Volume 24, Issue 1, January 3, 2023 International Journal of Molecular Sciences, co-authored by Hongyan Wu of Dalian University of Technology and Toshiyuki Nakamura of Graduate School of Environmental and Life Sciences, Okayama University. In it, the researchers demonstrate that CAFs protect cells from hydrogen peroxide-induced stress, providing evidence for the antioxidant properties of CAFs. Although hydrogen peroxide is a byproduct of cellular metabolic processes, abnormal amounts of this compound can be toxic to cells and cause irreversible damage. Treatment of cells with CAFs increased their resistance to hydrogen peroxide-induced toxic stress. In addition, CAF provided better protection against hydrogen peroxide-induced stress compared with α-tocopherol and γ-tocopherol, two important antioxidant compounds previously speculated to be major contributors to the antioxidant capacity of brown rice .
According to the study’s estimates, whole-grain brown rice contains five times more CAF than other antioxidant compounds found in brown rice. In addition, CAF increases the concentration of heme oxygenase-1, or HO-1, an enzyme that promotes the production of antioxidants. “Here we demonstrate that CAF significantly increases the mRNA levels of HO-1, a small molecular weight antioxidant-producing enzyme, at concentrations similar to those required for cytoprotection against oxidative damage“Professor Nakamura explained.
The researchers further explored this mechanism of action through experiments in which blocking HO-1 activity using an inhibitor greatly reduced the antioxidant effect of CAF. The high abundance and unique mechanism of action prove that CAF is the main antioxidant in brown rice.
With this study, researchers not only unlocked the secrets to brown rice’s health benefits, but also pinpointed the components that are responsible for those benefits. This will allow the development of new and better supplements and consumer health-focused food products using CAF. As the optimistic Professor Nakamura puts it, “Our research can help in the development of novel functional foods and supplements based on CAF functions, such as CAF-based nutraceuticals.“
Even though brown rice has such naturally occurring health benefits, brown rice is still a great fit on the menu!
Wu, H., Wait. (2023) Cycloartenyl ferate, the major compound in brown rice, has cytoprotective potential against oxidative stress-induced cytotoxicity. International Journal of Molecular Sciences. doi.org/10.3390/ijms24010822.