Protective effect of arabinose and sugar beet pulp against high glucose-induced oxidative stress in LLC-PK1 cells

Assessing Metabolic Differences Associated with Exposure to Polybrominated Biphenyl and Polychlorinated Biphenyls in the Michigan PBB Registry

BACKGROUND

Polybrominated biphenyls (PBB) and polychlorinated biphenyls (PCB) are persistent organic pollutants with potential endocrine-disrupting effects linked to adverse health outcomes.

OBJECTIVES

In this study, we utilize high-resolution metabolomics (HRM) to identify internal exposure and biological responses underlying PCB and multigenerational PBB exposure for participants enrolled in the Michigan PBB Registry.

METHODS

HRM profiling was conducted on plasma samples collected from 2013 to 2014 from a subset of participants enrolled in the Michigan PBB Registry, including 369 directly exposed individuals (F0) who were alive when PBB mixtures were accidentally introduced into the food chain and 129 participants exposed to PBB in utero or through breastfeeding, if applicable (F1). Metabolome-wide association studies were performed for PBB-153 separately for each generation and Σ PCB (PCB-118, PCB-138, PCB-153, and PCB-180) in the two generations combined, as both had direct PCB exposure. Metabolite and metabolic pathway alterations were evaluated following a well-established untargeted HRM workflow.

RESULTS

Mean levels were 1.75  ng / mL [standard deviation (SD): 13.9] for PBB-153 and 1.04  ng / mL (SD: 0.788) for Σ PCB . Sixty-two and 26 metabolic features were significantly associated with PBB-153 in F0 and F1 [false discovery rate (FDR) p < 0.2 ], respectively. There were 2,861 features associated with Σ PCB (FDR p < 0.2 ). Metabolic pathway enrichment analysis using a bioinformatics tool revealed perturbations associated with Σ PCB in numerous oxidative stress and inflammation pathways (e.g., carnitine shuttle, glycosphingolipid, and vitamin B9 metabolism). Metabolic perturbations associated with PBB-153 in F0 were related to oxidative stress (e.g., pentose phosphate and vitamin C metabolism) and in F1 were related to energy production (e.g., pyrimidine, amino sugars, and lysine metabolism). Using authentic chemical standards, we confirmed the chemical identity of 29 metabolites associated with Σ PCB levels (level 1 evidence).

CONCLUSIONS

Our results demonstrate that serum PBB-153 is associated with alterations in inflammation and oxidative stress-related pathways, which differed when stratified by generation. We also found that Σ PCB was associated with the downregulation of important neurotransmitters, serotonin, and 4-aminobutanoate. These findings provide novel insights for future investigations of molecular mechanisms underlying PBB and PCB exposure on health. https://doi.org/10.1289/EHP12657.

Antiobesity effect of L-arabinose via ameliorating insulin resistance and modulating gut microbiota in obese mice

OBJECTIVES

The global prevalence of obesity, a chronically trophic metabolic disease, has garnered significant attention. The aim of this study was to investigate L-arabinose, a unique functional sugar that improves insulin resistance and intestinal environment while promoting probiotic proliferation, for its potential in preventing obesity induced by a high-fat and high-sugar (HFHS) diet in mice.

METHODS

The L-arabinose group was intragastrically administered with 0.4 mL 60 mg/(kg body weight) L-arabinose for 8 wk. The metformin group was intragastrically administered at 0.4 mL 300 mg/(kg body weight), as a positive control group.

RESULTS

Treatment with L-arabinose resulted in a reduction of various obesity symptoms, such as prevented weight gain, increased liver-to-body ratio, decreased insulin, homeostasis model assessment for insulin resistance (HOMA-IR) index, and lipopolysaccharide (LPS) levels, as well as improved insulin resistance, reduced fat volume, inhibited hepatic steatosis, and repaired the pancreas. The L-arabinose treatment also improved lipid metabolism and inflammatory response, decreased the Firmicutes-to-Bacteroidetes ratio at the phylum level, and increased the relative abundance of Parabacteroides gordonii and Akkermansia muciniphila at the species level.

CONCLUSION

Based on these results, L-arabinose could be a promising candidate for combating obesity and obesity-related diseases by regulating insulin resistance and gut microbiota.

Oat β-glucan and L-arabinose synergistically ameliorate glucose uptake in insulin-resistant HepG2 cells and exert anti-diabetic activity via activation of the PI3K/AKT pathway in db/db mice

Oat β-glucan (OBG) and L-arabinose (LA) have exhibited positive effects on diabetes and its complications. However, it is unclear whether OBG and LA have a synergistic effect. We investigated the effect of variable compositions (OBG : LA = 1 : 1, 1 : 2, 1 : 4,1 : 6, 1 : 8, 1 : 10, 2 : 1, 4 : 1, 6 : 1, 8 : 1, 10 : 1) on glucose uptake in IR-HepG2 cells induced by dexamethasone (DEX) to find out the optimal composition showing synergistic effects. Furthermore, this study evaluated the anti-diabetic activity of the optimal composition in db/db mice. In vitro, the OBG : LA = 1 : 1 group showed the strongest synergistic effects among the varied compositions, outperforming OBG and LA alone. In vivo, there were more beneficial effects in the OBG : LA = 1 : 1 group compared with the OBG and LA single-dosing groups. OBG : LA = 1 : 1 supplementation markedly decreased the levels of fasting blood glucose (FBG) and insulin (INS) in serum, improved glucose tolerance and insulin sensitivity, lowered blood lipid levels, and reduced liver lipid accumulation. Moreover, the western blot results indicated that the OBG : LA = 1 : 1 group up-regulated the protein expression of glucose transporter-4 (GLUT4), phosphatidylinositol 3-kinase (PI3K), and phospho-protein kinase B (p-AKT), while down-regulating the protein expression of phospho-phosphorylated insulin receptor substrate-1 (p-IRS1) to enhance insulin transduction in liver tissues. These findings suggest that OBG : LA = 1 : 1 synergistically ameliorated glucose metabolism disorders and alleviated insulin resistance by promoting the PI3K/AKT pathway in the liver.

Effects of L-arabinose by hypoglycemic and modulating gut microbiome in a high-fat diet- and streptozotocin-induced mouse model of type 2 diabetes mellitus

L-arabinose is a good and healthy food additive. This study was conducted to investigate the effect of L-arabinose in a mouse model of type 2 diabetes mellitus (T2DM) induced by exposure to a high-fat diet (HFD) and streptozotocin (STZ). The model mice received L-arabinose at 20 and 60 mg (kg body weight [bw])^-1 d^-1 , metformin at 300 mg (kg bw)^-1 d^-1 (positive control) or sterile water (control) via oral gavage. Compared with the model group, mice treated with L-arabinose exhibited attenuated symptoms of diabetes mellitus, including a slower rate of body weight loss, increased homeostasis model assessment of β-cell function index levels, decreased blood glucose, alleviation of steatosis, and repair of pancreatic islet cells. L-arabinose also exerted an anti-inflammatory effect and partially mitigated dyslipidemia. A 16S-rRNA sequence analysis of the gut microbiota revealed that at the phylum level, treatment with L-arabinose significantly reduced the ratio of Firmicutes to Bacteroidetes due to a decreased relative abundance of Firmicutes; at the genus level, it reversed the increase in the relative abundance of Allobaculum and the decrease abundance of Oscillospira caused by exposure to an HFD and STZ. And the model mice received L-arabinose at 20 mg (kg bw)^-1 d^-1 had a better effect on improving T2DM than the high-dose group supplemented L-arabinose at 60 mg (kg bw)^-1 d^-1 . These results strongly suggest L-arabinose as an excellent candidate supplement to prevent or treat T2DM. PRACTICAL APPLICATIONS: L-arabinose, xylitol and sucralose are well-known substitutes for sucrose. L-arabinose has been reported to have beneficial effects on hyperglycemia, glycemic index, and fat accumulation. In this study, we found that low-dose (20 mg (kg bw)^-1 d^-1 ) supplementation of L-arabinose significantly improved glucose intolerance and gut microbiota incoordination in T2DM caused by HFD and STZ.

L-Arabinose suppresses gluconeogenesis through modulating AMP-activated protein kinase in metabolic disorder mice

l-Arabinose is a kind of plant-specific five-carbon aldose with benefits in type 2 diabetes mellitus. It has been shown to have good properties in improving glucose homeostasis, but the underlying molecular mechanisms are still not clear. Hepatic gluconeogenesis is critical for regulating glucose homeostasis. Here, this study aimed to investigate whether l-arabinose could improve glucose metabolism via suppressing hepatic gluconeogenesis. High-fat-high-sucrose diet (HFHSD) or high-sucrose diet (HSD)-fed mice were supplemented with or without l-arabinose for 12 weeks. Fasting blood glucose levels were measured and glucose tolerance test and the histological analysis were performed after l-arabinose administration. AMP-activated protein kinase (AMPK), acetyl-CoA carboxylase (ACC), peroxisome proliferator activated receptor-γ coactivator-1α (PGC1α), Forkhead box O1 (FoxO1), phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) expression levels were determined by RT-PCR and western blotting. As expected, l-arabinose apparently decreased body weight and attenuated hyperglycemia and glucose intolerance caused by HFHSD or HSD. l-Arabinose also had beneficial effects on glycogen synthesis by inactivating GSK3β. The expression levels of gluconeogenic genes were all decreased by l-arabinose administration in vivo and in vitro. In addition, our work revealed that AMPK is required for the inhibitory effects of l-arabinose on hepatic gluconeogenesis. l-Arabinose significantly up-regulated the phosphorylated levels of AMPK and its downstream protein ACC. Furthermore, blocking AMPK signaling through an inhibitor (compound C) or siAMPK significantly attenuated the inhibition of hepatic gluconeogenesis and the promotion of glycogen synthesis with l-arabinose, indicating that the inhibitory effect of l-arabinose on hepatic gluconeogenesis was AMPK dependent. Our work revealed that l-arabinose is a promising natural product for the regulation of hyperglycemia through inhibition of hepatic gluconeogenesis by activating AMPK.

Pentose metabolism and conversion to biofuels and high-value chemicals in yeasts

Pentose sugars are widespread in nature and two of them, D-xylose and L-arabinose belong to the most abundant sugars being the second and third by abundance sugars in dry plant biomass (lignocellulose) and in general on planet. Therefore, it is not surprising that metabolism and bioconversion of these pentoses attract much attention. Several different pathways of D-xylose and L-arabinose catabolism in bacteria and yeasts are known. There are even more common and really ubiquitous though not so abundant pentoses, D-ribose and 2-deoxy-D-ribose, the constituents of all living cells. Thus, ribose metabolism is example of endogenous metabolism whereas metabolism of other pentoses, including xylose and L-arabinose, represents examples of the metabolism of foreign exogenous compounds which normally are not constituents of yeast cells. As a rule, pentose degradation by the wild-type strains of microorganisms does not lead to accumulation of high amounts of valuable substances; however, productive strains have been obtained by random selection and metabolic engineering. There are numerous reviews on xylose and (less) L-arabinose metabolism and conversion to high value substances; however, they mostly are devoted to bacteria or the yeast Saccharomyces cerevisiae. This review is devoted to reviewing pentose metabolism and bioconversion mostly in non-conventional yeasts, which naturally metabolize xylose. Pentose metabolism in the recombinant strains of S. cerevisiae is also considered for comparison. The available data on ribose, xylose, L-arabinose transport, metabolism, regulation of these processes, interaction with glucose catabolism and construction of the productive strains of high-value chemicals or pentose (ribose) itself are described. In addition, genome studies of the natural xylose metabolizing yeasts and available tools for their molecular research are reviewed. Metabolism of other pentoses (2-deoxyribose, D-arabinose, lyxose) is briefly reviewed.

Metabolites analysis for cold-resistant yeast (Wickerhamomyces anomalus) strains own antioxidant activity on cold stored fish mince

The effect of eight cold-resistant yeast strains (J3, J7, J8, J9, J12, J15, J18, and J25) of Wickerhamomyces anomalus on the lipid oxidation of cold stored fish mince (4 °C) were investigated. And the metabolites of these yeast were determined with gas chromatography-mass spectrometry. These strains could effectively inhibit the increase of hydroperoxides value (p < 0.05), and the inhibiting rate was positively correlated with the content of isolongifolene, xylitol, turanose, thymol-glucoside, and uridine. Especially, the J3, J7, J8, J9, J12, and J18 could eliminate a large part of thiobarbituric acid reactive substances (TBARS) (p < 0.05), the eliminating rate was proportionate to the aldehyde dehydrogenase activity. Several bacteriostatic metabolites were detected: thymol-glucoside, 2-phenylethanol, cedro, and 2,4-bis (1,1-dimethylethyl) phenol. In addition, W. anomalus produced many metabolites with fruit and floral notes. In conclusion, cold-resistant W. anomalus strains own antioxidant activity were potential new bio-preservatives in the cold storage of muscle products.

Improvement of nutritional components and in vitro antioxidative properties of soy-powder yogurts using Lactobacillus plantarum

This research was the first to demonstrate changes in nutritional compositions (isoflavone and CLA) from the 50% methanol extracts of soy-powder milk (SPM) and soy-powder yogurt (SPY) through fermentation using Lactobacillus plantarum S48 and P1201 strains. The radical scavenging activities and protective effects against oxidative stress in LLC-PK₁ cells were also investigated. The average physicochemical characteristics including acidity and viable cell number as well as β-glucosidase activity increased with 0.2 → 0.7%, 7.5 → 9.8 log cfu/mL, and 0.0 3 → 1.75 U/g in SPYs. Total average isoflavones were considerably reduced (3180.3 → 2018.3 μg/g) with the increase of aglycone contents (191.8 → 770.2 μg/g), especially, daidzein exhibited the most remarkable increase rate (98.6 → 460.9 μg/g; > 4.8 times) during fermentation. The CLA and total phenolics also increased with significant differences (ND → 1.6 mg/g; 2.4 → 3.6 mg/GAE/g) between SPM and SPY. Interestingly, the cis-9, trans-11 CLA showed approximately 90% in total content. Moreover, the scavenging capacities against three radicals markedly increased with about 30% in SPYs, as the following order: ABTS > hydroxyl > DPPH. The protective effects on oxidative stress (py-rogallol: O2-, SNP: NO, and SIN-1: ONOO⁻) were also observed high cell viabilities (>10%) under LLC-PK₁ cellular system. Our results suggest that SPY may be utilized as a potent source regarding natural antioxidants and beneficial components for health food and medical uses.

Protective effects of L-arabinose in high-carbohydrate, high-fat diet-induced metabolic syndrome in rats

BACKGROUND

L-Arabinose is a non-caloric sugar, which could affect glucose and lipid metabolism and suppress obesity. However, few reports have described the effect of L-arabinose in metabolic syndrome, a combination of medical disorders that increase the risk of diabetes and cardiovascular disease.

OBJECTIVE

This study was conducted to explore the effects of L-arabinose in rats with metabolic syndrome induced by a high-carbohydrate, high-fat (HCHF) diet.

METHODS

After the rat model for metabolic syndrome was successfully established, L-arabinose was administrated by oral gavage for 6 weeks. The biochemical index and histological analysis were measured, and the expression levels of genes related to fatty acid metabolism were analyzed using real-time PCR.

RESULTS

Following treatment with L-arabinose, metabolic syndrome rats had an obvious reduction in body weight, systolic blood pressure, diastolic blood pressure, fasting blood glucose, triglycerides, total cholesterol, serum insulin, TNF-α, and leptin. Further study showed that treatment with L-arabinose significantly increased the expression of mRNA for hepatic CPT-1α and PDK4, but the expression of mRNA for hepatic ACCα was reduced.

CONCLUSIONS

This work suggests that L-arabinose could lower body weight, Lee's index, and visceral index and improve dyslipidemia, insulin resistance, inflammation, and viscera function, which indicate that it might be a promising candidate for therapies combating metabolic syndrome.

Protective effect of marine brown algal polyphenols against oxidative stressed zebrafish with high glucose

We observed that exposure to phlorotannins, which include 6,6-bieckol, phloroeckol, dieckol and phlorofucofuroeckol isolated from an edible brown alga, Ecklonia cava, significantly inhibited high glucose–induced ROS and cell death.