Bioaccessible (poly)phenol metabolites from raspberry protect neural cells from oxidative stress and attenuate microglia activation
Neuroinflammation is an integral part of the neurodegeneration process inherent to several aging dysfunctions. Within the central nervous system, microglia are the effective immune cells, responsible for neuroinflammatory responses. In this study, raspberries were subjected to in vitro digestion simulation to obtain the components that result from the gastrointestinal (GI) conditions, which would be bioaccessible and available for blood uptake. Both the original raspberry extract and the gastrointestinal bioaccessible (GIB) fraction protected neuronal and microglia cells against H2O2-induced oxidative stress and lipopolysaccharide (LPS)-induced inflammation, at low concentrations. Furthermore, this neuroprotective capacity was independent of intracellular ROS scavenging mechanisms. We show for the first time that raspberry metabolites present in the GIB fraction significantly inhibited microglial pro-inflammatory activation by LPS, through the inhibition of Iba1 expression, TNF-alpha release and NO production. Altogether, this study reveals that raspberry polyphenols may present a dietary route to the retardation or amelioration of neurodegenerative-related dysfunctions. (C) 2016 Elsevier Ltd. All rights reserved. ; This work was supported by iNOVA4Health Research Unit (LISBOA-01-0145-FEDER-007344), which is co-funded by Fundacao para a Ciencia e Tecnologia (FCT)/Ministerio da Ciencia e do Ensino Superior, through national funds, and by Fundo Europeu de Desenvolvimento Regional FEDER (Portugal) under the PT2020 Partnership Agreement. The study was also supported by the FCT projects PTDC/SAU-FAR/118787/2010 and in part by UID/DTP/04138/2013 and the IF/01097/2013 (CNS). Moreover, the authors would also acknowledge the support of the EUBerry FP7 KBBE-2010-4 265942 (DS and CNS), BacHBerry FP7-KBBE-2013-613793 (DS, GG and CNS) and SFRH/BD/86584/2012 (IF). The authors (DS and GMD) also specially acknowledge for the support from the Scottish Government's Rural and Environment Science and Analytical Services Division ...