gamma-oryzanol and ferulic-acid

Steryl ferulates (SFs) belong to the bioactive lipids contributing to the health promoting effects of whole grains. However, their intestinal absorption remains unclear. We investigated the permeation of individual SFs using an in vitro intestinal barrier model.. An in vitro Caco-2 cell monolayer, mimicking the intestinal barrier, was used to evaluate the permeation of eight SFs from different sources. A method based on ultra-performance LC with high-resolution mass spectrometric detection was developed for their quantification. Although only a negligible amount (< 0.5%) permeated across the Caco-2 cell monolayer, some differences in the permeability coefficients were observed between individual SFs. Permeation mechanism was mainly passive diffusion.. This work indicates that the permeation of SFs across the gut is very low. Therefore, cholesterol lowering and antioxidant activity-related health benefits of SFs most likely occur in the gut independently from absorption.

Topics: Caco-2 Cells; Cell Survival; Coumaric Acids; Dietary Fiber; Esters; Humans; Intestinal Absorption; Intestines; Mass Spectrometry; Models, Biological; Permeability; Phytosterols; Whole Grains

Polished and cargo rice, wild rice, rice bran, corn bran, and wheat bran were subjected to a static in vitro digestion model, to monitor changes in their steryl ferulate content and composition. Free sterols, possible hydrolysis products of steryl ferulates, were also measured. Additionally, steryl ferulate bioaccessibility was calculated as the percentage of steryl ferulates liberated from the grain matrix into the digestive juice. Steryl ferulate content ranged between 6.1 and 3900 μg/g and decreased by 1-63% due to digestion. A parallel increase in free sterols of more than 70% was observed in all samples. Additionally, bioaccessibility of steryl ferulates was found to be almost negligible. These findings suggest that intestinal enzymes immediately hydrolyze steryl ferulates, which are liberated from the grain matrix, and thus they are practically unavailable for absorption in the small intestine. This further indicates that the hydrolysis products of steryl ferulates could be bioactive in the gut.

Topics: Biological Availability; Coumaric Acids; Dietary Fiber; Digestion; Hydrolysis; In Vitro Techniques; Intestinal Absorption; Oryza; Phytosterols; Seeds; Zea mays