Phenolics from pigmented grains have remarkable immunomodulating properties

INTRODUCTION: Pigmented grains are of interest in functional foods because of their antioxidant properties, due to their high content in phenolics and anthocyanins. These compounds have been often associated with protection against chronic diseases (Doi:10.2174/1874256401004010007).The purpose of this study was to investigate the anti-inflammatory activities of extracts from the outermost parts of pigmented grains using intestinal epithelial Caco-2 cells as models. METHODS: When required and as appropriate, pigmented grains were de-branned in a pilot debranning plant, and milled in a lab-scale milling system. Phenolics were extracted with an ethanol/water mixture (65:35 v/v) containing 0.01% HCl. Analytical profiling of the phenolics was carried out by HPLC on the extracts. A DPPH assay was used to investigate the anti-oxidant activity of individual fractions. The anti-inflammatory properties of extracts were assessed by using cytokine-stimulated biosynthesis of a luciferase-labeled reporter of cytokine-related gene activation in transformed Caco-2 cells, using red grape cyanidines as a positive control (Doi: 10.1111/j.1365-2621.2012.03197.x) RESULTS: Analytical profiling of the phenolics indicated that the outermost fraction of debranned pigmented grains represents a rich and convenient source of phenolics (and fiber, as assessed by independent measurements). The anthocyanin-rich fraction decreased the immune response of Caco-2 cells in a dose-responsive manner, and grain phenolics were apparently more effective than grape cyanidins, that reportedly possess a strong anti-inflammatory activity (Doi: 10.1111/j.1365-2621.2012.03197.x). CONCLUSIONS: Our results indicate that the phenolics-rich fraction from pigmented grains appears to be at least twice more effective than phenolics from other sources (such as grape skin) in impairing the expression of NF-κB in appropriately stimulated transformed cells. From a practical standpoint, it is noteworthy that these bioactive-rich fractions can be incorporated with minimal efforts in ready-to consume staple foods, such as pasta (doi: 10.1161/circulationaha.112.122408 & doi: 10.1002/mnfr.201100526 ). Further studies will also address the bioavailability of grain-derrived anthocyanins and the amount of metabolites formed/released in the gastrointestinal tract, also in consideration of the activity of the local microflora and of its interactions with phenolics-enriched foods.