The neuroprotective effects of polyphenols, their role in innate immunity and the interplay with the microbiota

Effects of Nutrition on Cognitive Function in Adults with or without Cognitive Impairment: A Systematic Review of Randomized Controlled Clinical Trials

“…They can reduce lipid peroxidation, protein and DNA oxidation, modulate the immune system and regulate synaptic activity and axonal density [113]. Several studies also suggest that they mediate microglia cells through the gut-brain axis, thus regulating the release of pro-inflammatory cytokines, which have a detrimental role in cognitive impairment [114,115]. DHA also stimulates neuronal plasticity through the Akt pathway and the neurotrophin BDNF, a signaling molecule that modulates synaptic plasticity and protects against neuronal apoptosis [116], but also influences energy metabolism, insulin sensitivity and glucose and lipid metabolism [117].…”

Plant-Based Polyphenols: Anti-Helicobacter pylori Effect and Improvement of Gut Microbiota

“…These bioactive compounds have different phenolic hydroxyl groups in their structure, and thus, it is possible to identify phenolic acids, tannins, carotenoids, flavonoids, anthocyanins, and proanthocyanidins, among others, where the molecules present a wide variety of concentrations in the foods [ 20 ]. Thereby, polyphenols display a myriad of health-beneficial properties on the human body, since these components have demonstrated different medicinal and nutraceutical properties, helping in the gastrointestinal digestion [ 21 ], reducing the blood lipid levels [ 22 ], improving the body immunity [ 23 ], and in addition, polyphenols present neuroprotective, cardioprotective, anti-inflammatory, anti-diabetic, anti-carcinogenic, and anti-ageing effects, among other health improvements [ 24 , 25 , 26 ]. Nonetheless, despite all advantages of polyphenols, these components are very bitter and astringent tastes, making it difficult to incorporate into food or model foods [ 27 ], and also, polyphenols are unstable under certain conditions such as exposure to light, presence of oxygen and enzymes, high temperatures, and pH changes, weakening their activity [ 28 , 29 , 30 ].…”

Fermented natural product targeting gut microbiota regulate immunity and anti-inflammatory activity: A possible way to prevent COVID-19 in daily diet

“…Active substances extracted from natural products have shown significant biological activity in improving gut microbiota and regulating immunity ( Chen et al, 2021 , Annunziata et al, 2021 ) ( FIG. 2 ) ( Table 1 ).…”