Rice Bran Shows Potential as a Dietary Anticancer Agent

Researchers at Colorado State University (Fort Collins, USA) reviewed the current biomedical status of rice bran in a paper published in the September 2012 issue of the journal Advances in Nutrition.

They reported that the chemopreventive attributes of rice bran are due to the presence of bioactive phytochemicals such as ferulic acid, tricin, beta-sitosterol, gamma-oryzanol, tocotrienols/tocopherols, and phytic acid.

The researchers cited studies, which showed that the anticancer effects of rice bran's bioactive components were mediated through their ability to induce apoptosis, inhibit cell proliferation, and alter cell cycle progression in malignant cells. Rice bran's bioactive components protected against tissue damage through the scavenging of free radicals and the blocking of chronic inflammatory responses. These bioactive phytochemicals were shown to activate anticancer immune responses as well as affecting the colonic tumor microenvironment in favor of suppressing the development of colorectal cancer. This was accomplished through the modulation of gut microflora communities and the regulation of carcinogen-metabolizing enzymes.

“While I have been trained as a molecular toxicologist, I am excited about the opportunities to deliver bioactive, cancer fighting compounds with food, and this has led to my focus now primarily on the multiple drug-like characteristics of rice bran,” said senior author Dr. Elizabeth P. Ryan, assistant professor of environmental and radiological health sciences at Colorado State University. “There is a delicate balance of bioactive components in rice bran that together show anticancer activity including the ability to inhibit cell proliferation, alter cell cycle progression and initiate the programmed cell death known as apoptosis in malignant cells. We are working now to tease apart the ratios of these active molecules required for bioactivity and mechanisms. Previous attempts to isolate one or another compound have been largely unsuccessful and so it looks now as if rather than any one compound giving rice bran its chemopreventive powers, it is the synergistic activity of multiple components in the whole food that should be studied.”

“There are well over 100,000 varieties of rice in the world, many with their own unique mix of bioactive components, and so one major challenge is to discover the optimal composition for chemoprevention. Another challenge is ensuring that people consistently receive the required daily intake amount or "dose" needed to demonstrate these chemoprotective effects. That said, rice is an accessible, low-cost food in most places of the world, and so work with rice bran as a dietary chemopreventive agent has the potential to impact a significant portion of the world’s population,” said Dr. Ryan.

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Colorado State University