Highland Barley Whole Grain (Hordeum vulgare L.) Ameliorates Hyperlipidemia by Modulating Cecal Microbiota, miRNAs, and AMPK Pathways in Leptin Receptor-Deficient db/db Mice

Procyanidin B1 and Coumaric Acid from Highland Barley Alleviated High-Fat-Diet-Induced Hyperlipidemia by Regulating PPARα-Mediated Hepatic Lipid Metabolism and Gut Microbiota in Diabetic C57BL/6J Mice

A whole-grain highland barley (WHB) diet has been recognized to exhibit the potential for alleviating hyperlipidemia, which is mainly characterized by lipids accumulation in the serum and liver. Previously, procyanidin B1 (PB) and coumaric acid (CA) from WHB were found to alleviate serum lipid accumulation in impaired glucose tolerance mice, while the effect on modulating the hepatic lipid metabolism remains unknown. In this study, the results showed the supplementation of PB and CA activated the expression of peroxisome proliferator-activated receptor α (PPARα) and the target genes of cholesterol 7-α hydroxylase (CYP7A1) and carnitine palmitoyl transferase I (Cpt1) in the liver cells of high-fat-diet (HFD)-induced diabetic C57BL/6J mice, resulting in decreases in the serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL-C) contents, and an increase in the high-density lipoprotein (HDL-C) content. High-throughput sequencing of 16S rRNA indicated that supplementation with PB and CA ameliorated the gut microbiota dysbiosis, which was associated with a reduction in the relative abundance of Ruminococcaceae and an increase in the relative abundance of Lactobacillus, Desulfovibrio, and Akkermansia. Spearman's correlation analysis revealed that these genera were closely related to obesity-related indices. In summary, the activation of PPARα expression by PB and CA from WHB was important for the alleviation of hyperlipidemia and the structural adjustment of the gut microbiota.

Autoclaving-treated germinated brown rice relieves hyperlipidemia by modulating gut microbiota in humans

Introduction

Germinated brown rice is a functional food with a promising potential for alleviating metabolic diseases. This study aimed to explore the hypolipidemic effects of autoclaving-treated germinated brown rice (AGBR) and the underlying mechanisms involving gut microbiota.

Methods

Dietary intervention with AGBR or polished rice (PR) was implemented in patients with hyperlipidemia for 3 months, and blood lipids were analyzed. Nutritional characteristics of AGBR and PR were measured and compared. Additionally, 16S rDNA sequencing was performed to reveal the differences in gut microbiota between the AGBR and PR groups.

Results

AGBR relieves hyperlipidemia in patients, as evidenced by reduced levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein-B, and elevated levels of high-density lipoprotein cholesterol and apolipoprotein-A1. In terms of nutrition, AGBR had significantly higher concentrations of free amino acids (10/16 species), γ-aminobutyric acid, resistant starch, soluble dietary fiber, and flavonoids (11/13 species) than PR. In addition, higher microbial abundance, diversity, and uniformity were observed in the AGBR group than in the PR group. At the phylum level, AGBR reduced Firmicutes, Proteobacteria, Desulfobacterota, and Synergistota, and elevated Bacteroidota and Verrucomicrobiota. At the genus level, AGBR elevated Bacteroides, Faecalibacterium, Dialister, Prevotella, and Bifidobacterium, and reduced Escherichia-Shigella, Blautia, Romboutsia, and Turicibacter.

Discussion

AGBR contributes to the remission of hyperlipidemia by modulating the gut microbiota.

Barley consumption under a high-fat diet suppresses lipogenic genes through altered intestinal bile acid composition

We evaluated whether barley flour consumption in a high-fat environment affects lipid metabolism through signals mediated by bile acids. Four-week-old mice were fed a high-fat diet supplemented with cellulose (HC) or β-glucan-rich barley flour (HB) for 12 weeks. Bile acid composition in the intestinal tract and feces was measured by GC/MS. Gene expression levels involved in bile acid metabolism in the liver and intestinal tract were determined by RT-PCR. Similar parameters were measured in mice treated with antibiotics (antibiotics-cellulose [AC] and antibiotics-barley [AB]) to reduce the activity of intestinal bacteria. The Results showed that the HB group had lower liver blood cholesterol and triglyceride levels than the HC group. The HB group showed a significant decrease in primary bile acids in the gastrointestinal tract compared to the HC group. On the other hand, the concentration of secondary bile acids relatively increased in the cecum and feces. In the liver, Fxr activation suppressed gene expression levels in synthesizing bile acids and lipids. Furthermore, in the gastrointestinal tract, Tgr5 was activated by increased secondary bile acids. Correspondingly, AMP levels were increased in the HB group compared to the HC group, AMPK was phosphorylated in the liver, and gene expression involved in lipid synthesis was downregulated. A comparison of the AC and AB groups treated with antibiotics did not confirm these effects of barley intake. In summary, our results suggest that the prevention of lipid accumulation by barley consumption involves signaling through changes in bile acid composition in the intestinal tract.

Whole-grain highland barley premade biscuit prepared by hot-extrusion 3D printing: Printability and nutritional assessment

In this study, to explore the possibility of applying whole-grain highland barley (HB) in functional food, HB premade biscuit was created by hot-extrusion 3D printing (HEP) for the first time, and its printability and nutritional functions were evaluated. The rheology results showed 20% (w/w) HB suspension with 9% corn oil addition had better printability due to the formation of a structure with higher elasticity and stronger resistance to deformation. Moreover, the obtained premade biscuit had lower predicted glycemic index (pGI) and starch digestibility. Meanwhile, in vivo experiment results showed it could affect the glycolipid metabolism, ameliorate the high fat diet (HFD)-induced metabolic disorders and maintain the balance of the gut microbial ecology. This could be attributed to the decrease in Firmicutes/Bacteroidetes ratio and the proliferation of propionate-producing probiotics, especially Veilonella, Weissella and Desulfovibrio. Overall, this study could provide basic data and innovative approaches to prepare nutritional whole-grain foods.

d-Aspartate in Low-Protein Diets Improves the Pork Quality by Regulating Energy and Lipid Metabolism via the Gut Microbes

d-Aspartate is critical in maintaining hormone secretion and reproductive development in mammals. This study investigated the mechanism of different d-aspartate levels (0, 0.005, 0.05, and 0.5% d-aspartate) in low-protein diets on growth performance and meat quality by mediating the gut microbiota alteration in pigs. We found that adding 0.005% d-aspartate to a low-protein diet could dramatically improve the growth performance during the weaned and growing periods. Dietary d-aspartate with different levels markedly increased the back fat, and 0.5% d-aspartate significantly increased the redness in 24 h and reduced the shear force of the longissimus dorsi (LD) muscle. Moreover, d-aspartate treatments decreased the mRNA expression of MyHC II a and MyHC IIx in the LD muscle. The protein expression of MyH1, MyH7, TFAM, FOXO1, CAR, UCP2, and p-AMPK was upregulated by 0.005% d-aspartate. Additionally, the abundance of Alistipes, Akkermansia, and the [Eubacterium]_coprostanoligenes_group in the intestinal chyme of pigs was significantly decreased by d-aspartate treatments at the genus level, which was also accompanied by a significant decrease in acetate content. These differential microorganisms were significantly correlated with meat quality characteristics. These results indicated that d-aspartate in low-protein diets could improve the growth performance and meat quality in pigs by regulating energy and lipid metabolism via the alteration of gut microbiota.

Involvement of intestinal flora and miRNA into the mechanism of coarse grains improving type 2 diabetes: an overview

The prevalence of type 2 diabetes has been growing at an increasing rate worldwide. Dietary therapy is probably the easiest and least expensive method to prevent and treat diabetes. Previous studies have reported that coarse grains have anti-diabetic effects. Although considerable efforts have been made on the anti-diabetic function of different grains, the mechanisms of coarse grains on type 2 diabetes have not been systematically compared and summarized so far. Intestinal flora, reported as the main 'organ' of action underlying coarse grains, is an important factor in the alleviation of type 2 diabetes by coarse grains. Furthermore, microRNA (miRNA), as a new disease marker and 'dark nutrient', plays a likely influential role in cross-border communication among coarse grains, intestinal flora, and hosts. Given this context, this article reviews several possible mechanisms for the role of coarse grains on diabetes, incorporating resistance to inflammation and oxidative stress, repair of insulin signaling and β-cell dysfunction, and highlights the regulation of intestinal flora disorders and miRNAs expression, along with some novel insights. © 2022 Society of Chemical Industry.

Whole Grain Proso Millet (Panicum miliaceum L.) Attenuates Hyperglycemia in Type 2 Diabetic Mice: Involvement of miRNA Profile

This work aimed to investigate the hypoglycemic effects and underlying mechanism of whole grain proso millet (Panicum miliaceum L.; WPM) on type 2 diabetes mellitus (T2DM). The results showed that WPM supplementation significantly reduced fasting blood glucose (FBG) and serum lipid levels in T2DM mice induced by a high-fat diet (HFD) combined with streptozotocin (STZ), with improved glucose tolerance, liver and kidney injury, and insulin resistance. In addition, WPM significantly inhibited the expression of gluconeogenesis-related genes G6pase, Pepck, Foxo1, and Pgc-1α. Further study by miRNA high-throughput sequencing revealed that WPM supplementation mainly altered the liver miRNA expression profile of T2DM mice by increasing the expression of miR-144-3p_R-1 and miR-423-5p, reducing the expression of miR-22-5p_R-1 and miR-30a-3p. GO and KEGG analyses showed that the target genes of these miRNAs were mainly enriched in the PI3K/AKT signaling pathway. WPM supplementation significantly increased the level of PI3K, p-AKT, and GSK3β in the liver of T2DM mice. Taken together, WPM exerts antidiabetic effects by improving the miRNA profile and activating the PI3K/AKT signaling pathway to inhibit gluconeogenesis. This study implies that PM can act as a dietary supplement to attenuate T2DM.

CM3-SII polysaccharide obtained from Cordyceps militaris ameliorates hyperlipidemia in heterozygous LDLR-deficient hamsters by modulating gut microbiota and NPC1L1 and PPARα levels

Accumulating evidence has demonstrated that polysaccharides derived from edible fungi have lipid-lowering effects in mice. However, the lipid metabolism mechanisms in mice and humans are different. We have previously elucidated the structural characteristics of the alkali-extracted polysaccharide CM3-SII obtained from Cordyceps militaris. This study aimed to investigate whether CM3-SII could ameliorate hyperlipidemia in a heterozygous low-density lipoprotein receptor (LDLR)-deficient hamster model of hyperlipidemia. Our data demonstrated that CM3-SII significantly decreased total plasma cholesterol, non-high-density lipoprotein cholesterol, and triglyceride levels in heterozygous LDLR-deficient hamsters. Unlike ezetimibe, CM3-SII could enhance the concentration of plasma apolipoprotein A1 and the expression of liver X receptor α/ATP-binding cassette transporter G8 mRNA pathway and suppress the expression of Niemann-Pick C1-like 1, which help to reduce cholesterol levels further. Moreover, the results of molecular docking analysis demonstrated that CM3-SII could directly bind to Niemann-Pick C1-like 1 with high affinity. The triglyceride-lowering mechanisms of CM3-SII were related to its downregulation of sterol regulatory element-binding protein 1c and upregulation of peroxisome proliferator-activated receptor α. Importantly, CM3-SII increased the abundance of Actinobacteria and Faecalibaculum and the ratio of Bacteroidetes/Firmicutes. Thus, CM3-SII attenuated hyperlipidemia by modulating the expression of multiple molecules involved in lipid metabolism and the gut microbiota.

Modified Highland Barley Regulates Lipid Metabolism and Liver Injury in High Fat and Cholesterol Diet ICR Mice

Highland barley (Hordeum vulgare L. HB) has been demonstrated to have a series of dietotherapy values, including being low fat, low sugar, high fiber, and especially high in β-glucan. Long-term consumption could reduce the incidence of chronic diseases and metabolic syndromes. In this study, the regulating effect of modified highland barley (MHB) products, namely microwave fluidized HB, extruded and puffed HB, and ultrafine pulverized HB on lipid metabolism and liver injury in mice fed a high fat and cholesterol diet (HFCD) was investigated using microbiota diversity gene sequencing and untargeted metabolomics. A total of six groups of mice were supplemented with a normal diet or an HFCD, with or without MHB, and the experimental period lasted 10 weeks. The obtained results demonstrated that MHB supplementation could effectively reverse the increase in body weight gain and adipose tissue accumulation caused by an HFCD (p < 0.05). Moreover, serum biochemical parameters showed that MHB supplementation significantly decreased total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels, while increasing high-density lipoprotein cholesterol (HDL-C) levels. The results of hematoxylin and eosin (H&E) assays showed that MHB supplementation could significantly improve the liver injury and adipose tissue accumulation. In addition, 16S rRNA amplicon sequencing showed that MHB supplementation increased the bacteroidetes/firmicutes ratio and the abundance Lactobacillus abundance, while also decreasing the Proteobacteria abundance, which are bacteria closely associated with the hyperlipidemia caused by HFCD. LC-MS metabolomics indicated that MHB supplementation significantly enhanced the levels of Deoxycholic acid, Myclobutanil, 3-Epiecdysone, 3,4-Dihydroxybenzeneacetic acid, and so on. In addition, MHB supplementation promoted activation of the Arachidonic acid metabolism pathways, the expression of ABC transporters, bile secretion, primary bile acid biosynthesis, and so on. Above all, this study showed the potential capacity of MHB to relieve hyperlipidemia and provides a reference for developing a new dietary intervention supplement to ameliorate hyperlipidemia.

Synergistic Hypolipidemic Effects and Mechanisms of Phytochemicals: A Review

Hyperlipidemia, a chronic disorder of abnormal lipid metabolism, can induce obesity, diabetes, and cardiovascular and cerebrovascular diseases such as coronary heart disease, atherosclerosis, and hypertension. Increasing evidence indicates that phytochemicals may serve as a promising strategy for the prevention and management of hyperlipidemia and its complications. At the same time, the concept of synergistic hypolipidemic and its application in the food industry is rapidly increasing as a practical approach to preserve and improve the health-promoting effects of functional ingredients. The current review focuses on the effects of single phytochemicals on hyperlipidemia and its mechanisms. Due to the complexity of the lipid metabolism regulatory network, the synergistic regulation of different metabolic pathways or targets may be more effective than single pathways or targets in the treatment of hyperlipidemia. This review summarizes for the first time the synergistic hypolipidemic effects of different combinations of phytochemicals such as combinations of the same category of phytochemicals and combinations of different categories of phytochemicals. In addition, based on the different metabolic pathways or targets involved in synergistic effects, the possible mechanisms of synergistic hypolipidemic effects of the phytochemical combination are illustrated in this review. Hence, this review provides clues to boost more phytochemical synergistic hypolipidemic research and provides a theoretical basis for the development of phytochemicals with synergistic effects on hyperlipidemia and its complications.

Modified highland barley regulates lipid metabolism, liver inflammation and gut microbiota in high-fat/cholesterol diet mice as revealed by LC-MS based metabonomics

Highland barley (HB) displays a series of properties including regulation of lipid metabolism and attenuation of liver injury. Our study aimed to investigate the effect of modified highland barley (MHB) including fluidized highland barley (HB-1), extruded and puffed highland barley (HB-2), and ultrafine pulverized highland barley (HB-3) on lipid metabolism, liver inflammation, gut microbiota and metabolite profiles in mice fed with a high-fat/cholesterol diet (HFCD). 6 treatment groups were fed a normal control diet or an HFCD with or without MHB supplementation for 10 weeks. Results showed that MHB significantly improved lipid parameters, liver function and injury and blood glucose indexes related to hyperlipidemia compared with the HFCD group. In addition, MHB recovered the disorder of gut microbiota by increasing the Bacteroidetes/Firmicutes ratio and Lactobacillus and Allobaculum abundances and decreasing Proteobacteria abundance related to lipid metabolism bacteria. MHB reversed the decrease of short-chain fatty acid levels caused by the HFCD. Fecal metabolomics analysis showed that the important differential metabolites between HB-1 and HFCD were deoxycholic acid, myclobutanil and dibutyl phthalate, and the important differential metabolic pathways were arachidonic acid metabolism, ABC transporters and biosynthesis of unsaturated fatty acids. Results suggested that MHB especially HB-1 were better effective dietary intervention candidates to ameliorate hyperlipidemia compared with HB.

Portulaca oleracea L. Extract Regulates Hepatic Cholesterol Metabolism via the AMPK/MicroRNA-33/34a Pathway in Rats Fed a High-Cholesterol Diet

This study examined the effect of extruded Portulaca oleracea L. extract (PE) in rats fed a high-cholesterol diet through the AMP-activated protein kinase (AMPK) and microRNA (miR)-33/34a pathway. Sprague–Dawley rats were randomized into three groups and fed either a standard diet (SD), a high-cholesterol diet containing 1% cholesterol and 0.5% cholic acid (HC), or an HC diet containing 0.8% PE for 4 weeks. PE supplementation improved serum, liver, and fecal lipid profiles. PE upregulated the expression of genes involved in cholesterol efflux and bile acids’ synthesis such as liver X receptor alpha (LXRα), ATP-binding cassette subfamily G5/G8 (ABCG5/8), and cholesterol 7 alpha-hydroxylase (CYP7A1), and downregulated farnesoid X receptor (FXR) in the liver. In addition, hepatic gene expression levels of apolipoprotein A-l (apoA-1), paraoxonase 1 (PON1), ATP-binding cassette subfamily A1/G1 (ABCA1/G1), lecithin-cholesterol acyltransferase (LCAT), and scavenger receptor class B type 1 (SR-B1), which are related to serum high-density lipoprotein cholesterol metabolism, were upregulated by PE. Furthermore, hepatic AMPK activity in the PE group was higher than in the HC group, and miR-33/34a expression levels were suppressed. These results suggest that PE improves the cholesterol metabolism by modulating AMPK activation and miR-33/34a expression in the liver.

Research progress of signaling pathways of the natural substances intervene dyslipidemia (Review)

Dyslipidemia is an umbrella term for a range of lipid metabolic disorders in the body. This condition has been widely reported to greatly increase the risk of cardiovascular diseases, threatening human health. In recent years, advances in molecular biology have deepened understanding of the dyslipidemia-related signaling pathways and specific mechanisms underlying dyslipidemia. Signaling pathways possess the ability to transmit an extracellular signal to the inside of the cell, leading to specific biological effects. Lipid metabolism disorders and lipid levels in the blood are frequently affected by aberrant alterations in the dyslipidemia-related signaling pathways. Therefore, further investigations into these pathways are required for the prevention and treatment of dyslipidemia. The present review summarizes the characteristics of six dyslipidemia-associated signaling pathways: Peroxisome proliferator-activated receptor, adenosine monophosphate-activated protein kinase, farnesoid X receptor, forkhead box O, adipocytokine and cyclic adenosine monophosphate signaling pathways. In particular, specific focus was placed on previous experimental studies and reports on the intervention effects of natural substances (compounds from animals, plants, marine organisms and microorganisms) on dyslipidemia.

Beneficial Effects of Partly Milled Highland Barley on the Prevention of High-Fat Diet-Induced Glycometabolic Disorder and the Modulation of Gut Microbiota in Mice

The nutritional functions of highland barley (HB) are superior to those of regular cereals and have attracted increasing attention in recent years. The objective of this study was to investigate whether partly milled highland barley (PHB) can regulate the serum glucose and lipid disorders of mice fed a high-fat diet (HFD) and to further explore their potential gut microbiota modulatory effect. Our results showed that PHB supplementation significantly reduced fasting blood glucose (FBG) and improved oral glucose tolerance. Histological observations confirmed the ability of PHB to alleviate liver and intestine damage. Furthermore, the results of 16S amplicon sequencing revealed that PHB prevented a HFD-induced gut microbiota dysbiosis, enriching some beneficial bacteria, such as Lactobacillus, Bifidobacterium, and Ileibacterium, and reducing several HFD-dependent taxa (norank_f_Desulfovibrionaceae, Blautia, norank_f_Lachnospiraceae, unclassified_f_Lachnospiraceae, and Colidextribacter). In addition, the increase of Lactobacillus and Bifidobacterium presence has a slightly dose-dependent relationship with the amount of the added PHB. Spearman correlation analysis revealed that Lactobacillus and Bifidobacterium were negatively correlated with the blood glucose level of the oral glucose tolerance test. Overall, our results provide important information about the processing of highland barley to retain its hypoglycemic effect and improve its acceptability and biosafety.

Color, Starch Digestibility, and In Vitro Fermentation of Roasted Highland Barley Flour with Different Fractions

Highland barley (HB) is commonly milled into flour for direct consumption or further processed with other food formulations. Nevertheless, the association between milling and HB flour properties remains lacking. This work studied the effect of particle sizes (coarse, 250–500 μm; medium, 150–250 μm; fine, <150 μm) on physicochemical and nutritional properties of raw and sand-roasted HB flour. Gelatinization enthalpy decreased with increasing particle sizes of raw HB flour, while no endothermic transitions were observed in sand-roasted flour. Sand roasting destroyed starch granules and decreased short-range molecular order. Starch digestibility increased while total short-chain fatty acids (SCFAs) production decreased with decreasing particle sizes in all samples. The relative crystallinity of sand-roasted HB flour decreased by 80–88% compared with raw samples. Sand roasting raised in vitro starch digestibility, while total SCFAs during in vitro fecal fermentation decreased. Sand-roasted HB flour with particle sizes <150 μm had the highest starch digestibility (94.0%) but the lowest production of total SCFAs (1.89–2.24 mM). Pearson’s correlation analysis confirmed the relationship between the nutritional qualities of HB flour and milling.

Polyphenol extract and essential oil of Amomum tsao-ko equally alleviate hypercholesterolemia and modulate gut microbiota

This study explored the effects of polyphenol extract (TKP) and essential oil (TKO) from Amomum tsao-ko Crevost et Lemaire (tsao-ko) on plasma total cholesterol and gut microbiota. Four groups of hamsters (n = 8 each) were fed one of four diets, respectively, namely a high-cholesterol diet (HCD) containing 0.1% cholesterol, a HCD containing 0.5% cholestyramine (PCD), a HCD with daily oral administration of 1000 mg per kg body weight TKP, and a HCD with daily oral administration of 200 mg per kg body weight TKO for 6 weeks. TKP and TKO equally lowered plasma total cholesterol (TC) by 13-18% via increasing the fecal elimination of total acidic sterols by 50-191%. This might be due to up-regulation of liver cholesterol 7α-hydroxylase (CYP7A1) at both transcriptional and translational levels. At a family level, TKP and TKO diets favorably modified the relative abundance of Ruminococcaceae, Erysipelotrichaceae, and Desulfovibrionaceae associated with acidic sterols and CYP7A1. It was therefore concluded that TKP and TKO were equally effective in alleviating hypercholesterolemia in hamsters via the interaction between gut microbiota and bile acid metabolism.

Protective mechanism of mung bean coat against hyperlipidemia in mice fed with a high-fat diet: insight from hepatic transcriptome analysis

Mung bean coat (MBC) is a good source of dietary fibre and phenolic compounds with medical properties, and can alleviate metabolic diseases. In the present study, the effects of MBC on high fat diet (HFD)-induced hyperlipidemia mice were evaluated, and the underlying mechanisms of MBC against hyperlipidemia from hepatic transcriptional analysis were explored. Four groups of mice were fed a normal control diet or a HFD with or without MBC supplementation (6%, w/w) for 12 weeks. The results demonstrated that MBC supplementation could effectively alleviate HFD-induced obese symptoms, such as body weight gain and white adipose tissue accumulation. Notably, the serum lipid profiles, including total triglyceride, total cholesterol, and low-density lipoprotein cholesterol, were significantly lowered, accompanied by a significant improvement in hepatic steatosis. RNA-sequencing analysis indicated 1126 differential expression genes responding to MBC supplementation, and the PPAR signaling pathway was significantly enriched. Furthermore, MBC supplementation could significantly upregulate the transcriptional expression of lipid transformation (lipidolysis)-related genes (Cpt1b, Cyp7a1, and PPAR-α) and downregulate the transcriptional expression of lipid synthesis-related genes (Scd1, Cd36, and PPAR-γ) to protect against the HFD-induced hyperlipidemia, and they were confirmed by qRCR and western blotting validation. Taken together, the present study provides valuable information for understanding the curative effects and action mechanism of MBC in alleviating hyperlipidemia, and thus may contribute to the development and application of MBC as functional foods or dietary supplement to protect against hyperlipidemia.

Highland Barley and Its By-Products Enriched with Phenolic Compounds for Inhibition of Pyrraline Formation by Scavenging α-Dicarbonyl Compounds

Pyrraline, a typical kind of advanced glycation end product, has been found to contribute to the development of pathologies associated with ageing and diabetes mellitus. In the study, phenolic compounds extracted from highland barley whole grain (HBWG) and vinasse (HBVN) were used to inhibit pyrraline formation in a simulated food. The optimal extraction condition for HBWG and HBVN was using 8 mL of 50% acetone solution at 50 °C for 60 min. The extraction and identification of phenolic compounds from HBWG and HBVN were performed by UPLC-PAD-MS/MS. The inhibitory effects of pyrraline in the simulated food were 52.03% and 49.22% by HBVN and HBWG, respectively. The diphenyl picrylhydrazyl radical- and ferric-reducing ability of plasma assays was used to evaluate the antioxidant activity of the extracts. The main inhibition pathways and molecular mechanism of phenolic compounds on pyrraline regulation were explored by scavenging α-dicarbonyl compounds. The study demonstrated that highland barley and its by-products can potentially be used as a functional food to regulate pyrraline formation during food processing.

Alzheimer's Disease and Diabetes: Role of Diet, Microbiota and Inflammation in Preclinical Models

Alzheimer's disease (AD) is the most common cause of dementia. Epidemiological studies show the association between AD and type 2 diabetes (T2DM), although the mechanisms are not fully understood. Dietary habits and lifestyle, that are risk factors in both diseases, strongly modulate gut microbiota composition. Also, the brain-gut axis plays a relevant role in AD, diabetes and inflammation, through products of bacterial metabolism, like short-chain fatty acids. We provide a comprehensive review of current literature on the relation between dysbiosis, altered inflammatory cytokines profile and microglia in preclinical models of AD, T2DM and models that reproduce both diseases as commonly observed in the clinic. Increased proinflammatory cytokines, such as IL-1β and TNF-α, are widely detected. Microbiome analysis shows alterations in Actinobacteria, Bacteroidetes or Firmicutes phyla, among others. Altered α- and β-diversity is observed in mice depending on genotype, gender and age; therefore, alterations in bacteria taxa highly depend on the models and approaches. We also review the use of pre- and probiotic supplements, that by favoring a healthy microbiome ameliorate AD and T2DM pathologies. Whereas extensive studies have been carried out, further research would be necessary to fully understand the relation between diet, microbiome and inflammation in AD and T2DM.