New Research Links Rice Bran Compound to Relief From Irritable Bowel Syndrome - Video

A naturally occurring compound found in rice bran may help calm excessive intestinal contractions by blocking calcium signals that control gut muscle movement, according to a new study from Toho University. The findings suggest the compound could one day support dietary approaches for certain digestive disorders, including irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD).

Published by researchers from the university's Faculty of Pharmaceutical Sciences, the study investigated ferulic acid (FA), a plant-derived polyphenol commonly found in whole grains and rice bran. While ferulic acid is already recognized for its antioxidant and neuroprotective properties, its effects on intestinal movement had remained largely unexplored.

To examine its role, researchers tested ferulic acid on guinea pig intestinal smooth muscle. They found that the compound significantly reduced muscle contractions triggered by several naturally occurring signaling molecules, including acetylcholine, histamine, prostaglandin F2α, and serotonin.

The effect was both reversible and dose-dependent, meaning stronger inhibition occurred at higher concentrations, and normal muscle contractions returned once ferulic acid was removed.

Further experiments suggested that ferulic acid does not block the receptors for these signaling molecules directly. Instead, it appears to interfere with a shared mechanism required for muscle contraction.

The researchers found that ferulic acid reduced the movement of calcium into smooth muscle cells by inhibiting voltage-dependent calcium channels. Because calcium is essential for triggering muscle contraction, limiting calcium entry reduced the strength of intestinal contractions.

These findings suggest ferulic acid may help reduce excessive gut activity, potentially benefiting people with diarrhea-predominant IBS or IBD. However, the same effect could worsen symptoms in individuals with constipation-predominant IBS by slowing intestinal movement even further.

Although ferulic acid may reach higher levels inside the digestive tract after food consumption, clinical studies in humans are still needed to determine whether dietary intake or supplements can safely and effectively regulate intestinal motility.

REFERENCE: Keisuke Obara, Kento Yoshioka, et al.; Ferulic acid suppresses guinea pig ileal longitudinal smooth muscle contractions by inhibiting voltage-dependent Ca2 channels. Journal of Pharmacological Sciences, 2025; 158 (4): 289 DOI: 10.1016/j.jphs.2025.05.012