Pigmented cereals have remarkably anti-inflammatory and anti-diabetic effects

Anthocyanins in grains are expressed in either the pericarp or aleuronic layer of different cereal varieties. Many studies have shown the health-promoting effects of anthocyanins, that have anti-inflammatory and antidiabetic activities. In this study we have investigated the profile of phenolics in pigmented grains and tested their bioactive molecules as for efficacy on inflammation markers (by using Caco-2cells transfected with a pNiFty2-Luc vector), and as for their inhibitory activities against alpha-glucosidase and alpha-amylase. Analytical profiling of the anthocyanins in five different colored grains (three varieties of corn and two of wheat) was carried out by advanced LC methods. Total anthocyanins amount was determined using a pH differential method. Antioxidant capacity was measured as FRAP. Immunomodulating effects were assessed by testing cytokine-stimulated synthesis of a luciferase-labeled reporter of gene activation in transformed Caco-2 cell lines. Inhibition of alpha-amylase and alpha -lucosidase was assessed according to standard methods. Four major anthocyanins were characterized from HPLC profile. Cyanidine-3-glucoside was predominant both in corn and wheat samples. Purple wheat and Blue corn (T) had the highest anthocyanin contents (0.74 and 0.66 mg/g, respectively), followed by blue corn (MF) (0.53 mg/g) and a fraction from de-hulling of Skorpion wheat (0.18mg/g), that had the highest rutin content. The Rostrato variety of corn showed the highest antioxidant capacity (47.2 μmolFe(II)/g) between all samples. The highest amount of ferulic acid was observed in Blue corn (T) and Rostrato. The immune response of Caco-2 cells decreased significantly in a dose-responsive manner for all grains extracts. Extracts from blue wheat (cultivar SK) and purple wheat where effective in decreasing inflammatory response at anthocyanin concentrations comparable to those of pure cyanindin-3-glucoside. Purple wheat and blue corn (cultivar T) extracts also displayed significant inhibition of α-amylase activity. Values ranged between 78% (wheat) and 95.4% (corn) at final concentrations of extract solids in the 100-130 μg/ml range. Under comparable conditions, brush border α-glucosidase inhibition from the same extracts was 57.8 % (wheat) and 65.4% (corn). The present work highlights the potential health promoting effects of phenolic-rich extracts of pigmented grains. The enriched cereal fractions studied here can be stably and directly incorporated into staple food material like pasta, bread, noodles or snacks. Work is in progress to assess their possible role in regulating the intestinal microbiota.