1.
Bioavailability and metabolism of phenolic compounds from wholegrain wheat and aleurone-rich wheat bread.
Bresciani, L, Scazzina, F, Leonardi, R, Dall'Aglio, E, Newell, M, Dall'Asta, M, Melegari, C, Ray, S, Brighenti, F, Del Rio, D
Molecular nutrition & food research. 2016;(11):2343-2354
Abstract
SCOPE This work aimed at investigating absorption, metabolism, and bioavailability of phenolic compounds after consumption of wholegrain bread or bread enriched with an aleurone fraction. METHODS AND RESULTS Two commercially available breads were consumed by 15 participants on three occasions and matched for either the amount of ferulic acid in the bread or the amount of bread consumed. Urine was collected for 48 h from all the volunteers for phenolic metabolite quantification. Blood samples were collected for 24 h following bread consumption in five participants. A total of 12 and 4 phenolic metabolites were quantified in urine and plasma samples, respectively. Metabolites were sulfate and glucuronic acid conjugates of phenolic acids, and high concentrations of ferulic acid-4'-O-sulfate, dihydroferulic acid-4'-O-sulfate, and dihydroferulic acid-O-glucuronide were observed. The bioavailability of ferulic acid was significantly higher from the aleurone-enriched bread when all ferulic acid metabolites were accounted for. CONCLUSIONS The study shows that low amounts of aleurone-enriched bread resulted in equivalent plasma levels of ferulic acid as wholegrain bread. This could suggest that, if the absorbed phenolic metabolites after wholegrain product intake exert health benefits, equal levels could be reached through the consumption of lower doses of refined products enriched in aleurone fraction.
2.
Antiglycative and neuroprotective activity of colon-derived polyphenol catabolites.
Verzelloni, E, Pellacani, C, Tagliazucchi, D, Tagliaferri, S, Calani, L, Costa, LG, Brighenti, F, Borges, G, Crozier, A, Conte, A, et al
Molecular nutrition & food research. 2011;:S35-43
Abstract
SCOPE Dietary flavonoids and allied phenolic compounds are thought to be beneficial in the control of diabetes and its complications, because of their ability to inhibit oxidative stress, protein glycation and to act as neuroprotectants. Following ingestion by humans, polyphenolic compounds entering the large intestine undergo extensive metabolism by interaction with colonic microbiota and it is metabolites and catabolites of the parent compounds that enter the circulatory system. The aim of this study was to investigate the inhibitory activity of some colonic microbiota-derived polyphenol catabolites against advanced glycation endproducts formation in vitro and to determine their ability, at physiological concentrations, to counteract mild oxidative stress of cultured human neuron cells. METHODS AND RESULTS This study demonstrated that ellagitannin-derived catabolites (urolithins and pyrogallol) are the most effective antiglycative agents, whereas chlorogenic acid-derived catabolites (dihydrocaffeic acid, dihydroferulic acid and feruloylglycine) were most effective in combination in protecting neuronal cells in a conservative in vitro experimental model. CONCLUSION Some polyphenolic catabolites, generated in vivo in the colon, were able in vitro to counteract two key features of diabetic complications, i.e. protein glycation and neurodegeneration. These observations could lead to a better control of these events, which are usually correlated with hyperglycemia.