Germinated barley foodstuff exhibits different adsorption properties for hydrophilic versus hydrophobic bile acids

Background/Aims: Germinated barley foodstuff (GBF), a type of dietary fiber, exhibits therapeutic effects in ulcerative colitis (UC) patients. However, the precise mechanisms responsible for these effects are still under investigation. On the other hand, it has been suggested that bile salts in the gut lumen play an important role in the integrity of the intestinal mucosa. The aim of the present study was to investigate the ability of GBF to adsorb bile salts in vitro. Methods: The binding capacities of GBF, enzymatically digested GBF (GBF-fiber), and alpha-cellulose for unconjugated and conjugated bile salts were measured using Langmuir's method. The morphology of these fibers was observed by light and fluorescence microscopy. Results: GBF adsorbed bile salts very strongly, especially hydrophobic bile salts. Even after enzymatic digestion, the GBF fiber still exhibited strong binding capacity, whereas a-cellulose exhibited very low binding capacity. Microscopically, GBF consists mainly of aleurone, a lattice-like cell wall with cytoplasm enclosed. After enzymatic digestion, the cytoplasm was also digested. Conclusion: GBF possesses a great capacity to adsorb bile salts. This may be part of the mechanism for the therapeutic effects of GBF in UC patients.