Summary
Direct liquid fuel cell (DLFC) and membraneless fuel cell using the anode consisting of buckypaper (BP) and vitamin B12 (Vit B12) (BP/Vit B12) is introduced in physiological condition, while ...vitamin C (Vit C) is used as anodic fuel. Due to the high sensitivity of Vit B12 and the inherent feature of BP, the onset potential for the oxidation reaction of Vit C catalyzed by BP/Vit B12 is −0.1 V (vs Ag/AgCl), and its anodic current density measured at 0.3 V (vs Ag/AgCl) is 1.82 mA cm−2 even in a low Vit C concentration (10 mM). Regarding performance in fuel cells, maximum power density (MPD) of Vit C fuel cell containing membrane and Pt‐based air cathode is 0.62 ± 0.067 mW cm−2 in 0.01 M Vit C, and this is 3.1 times higher than that of fuel cell containing pristine BP. In addition, in a paper‐based flexible membraneless fuel cell using BP/bilirubin oxidase as cathode and the concentration of cerebrospinal fluid within the human body (0.35 mM Vit C), its MPD is 57.7 ± 4.02 μW cm−2. This means this suggested Vit C fuel cell system can replace the conventional primary batteries considered as the power source of implantable sensors and stimulation devices to treat neurological disorders.
We introduce the flexible membraneless fuel cells that employ buckypaper and vitamin B12 as an anodic catalyst, and use vitamin C as fuel. Their MPD is 57.7 ± 4.02 μW cm−2 when the same concentration of cerebrospinal fluid within the human body (0.35 mM vitamin C) is used.
Objective: To determine the effects of naturally derived probiotic strains individually or combination on a short‐term diet‐induced obesity model.
Design and Methods: C57BL/6J mice (n = 50) were ...randomly divided into five groups, then fed a high‐fat high‐cholesterol diet (HFCD), HFCD and Lactobacillus plantarum KY1032 (PL, 1010cfu/day), HFCD and Lactobacillus curvatus HY7601 (CU, 1010cfu/day), HFCD and in combination with PL+CU (1010cfu/day), or a normal diet (ND) for 9 weeks.
Results: PL and CU showed distinct and shared metabolic activity against a panel of 50 carbohydrates. Fat accumulation in adipose tissue and liver was significantly reduced by probiotic strains CU or PL+CU. Probiotic strains CU or PL+CU reduced cholesterol in plasma and liver, while PL+CL had a synergistic effect on hepatic triglycerides. Probiotic strains PL+CU combination was more effective for inhibiting gene expressions of various fatty acid synthesis enzymes in the liver, concomitant with decreases in fatty acid oxidation‐related enzyme activities and their gene expressions.
Conclusions: Multi‐strain probiotics may prove more beneficial than single‐strain probiotics to combat fat accumulation and metabolic alterations in diet‐induced obesity.
Enzymatic biofuel cells (EBCs) using non-toxic and naturally derived flavonoid biomediators as anodic catalysts are introduced. In this study, hesperidin, a flavonoid extracted from citrus fruits, ...served as a biomediator with flavine adenine dinucleotide dependent glucose dehydrogenase (FADGDH). Hesperidin exhibits several advantages, including a low onset potential, a robust catalytic activity, and an excellent stability for glucose oxidation reaction (GOR). This superiority can be attributed to its unique chemical structure and electrochemically activated capability. For its activation, a catechol group was produced on the right side of the phenyl ring of hesperidin, existing in both chemically and physically adsorbed forms. Following activation, a redox reaction occurred at a buckypaper (BP) supported electrode (BP/Activated Hesperidin (A-Hesperidin)) at −0.05 and 0.15 V (vs. Ag/AgCl). When BP/A-Hesperidin/FADGDH was employed, the reactivity of GOR reached 0.61 mA cm−2 at 0.3 V with 10 mmol L−1 glucose. These performances surpass those reported in similar research studies. When the EBC using BP/A-Hesperidin/FADGDH was operated, its maximum power density (MPD) reached 212.84 ± 17.97 μW cm−2 with 10 mmol L−1 glucose under air conditions. This confirms that A-Hesperidin can induce higher EBC performances than conventionally used mediators, which are often toxic and expensive.
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The gut microbiota has an important role in the gut barrier, inflammation and metabolic functions. Studies have identified a close association between the intestinal barrier and metabolic diseases, ...including obesity and type 2 diabetes (T2D). Recently, Akkermansia muciniphila has been reported as a beneficial bacterium that reduces gut barrier disruption and insulin resistance. Here we evaluated the role of A. muciniphila-derived extracellular vesicles (AmEVs) in the regulation of gut permeability. We found that there are more AmEVs in the fecal samples of healthy controls compared with those of patients with T2D. In addition, AmEV administration enhanced tight junction function, reduced body weight gain and improved glucose tolerance in high-fat diet (HFD)-induced diabetic mice. To test the direct effect of AmEVs on human epithelial cells, cultured Caco-2 cells were treated with these vesicles. AmEVs decreased the gut permeability of lipopolysaccharide-treated Caco-2 cells, whereas Escherichia coli-derived EVs had no significant effect. Interestingly, the expression of occludin was increased by AmEV treatment. Overall, these results imply that AmEVs may act as a functional moiety for controlling gut permeability and that the regulation of intestinal barrier integrity can improve metabolic functions in HFD-fed mice.
This study investigated the efficacy of chlorogenic acid on altering body fat in high-fat diet (37% calories from fat) induced-obese mice compared to caffeic acid. Caffeic acid or chlorogenic acid ...was supplemented with high-fat diet at 0.02% (wt/wt) dose. Both caffeic acid and chlorogenic acid significantly lowered body weight, visceral fat mass and plasma leptin and insulin levels compared to the high-fat control group. They also lowered triglyceride (in plasma, liver and heart) and cholesterol (in plasma, adipose tissue and heart) concentrations. Triglyceride content in adipose tissue was significantly lowered, whereas the plasma adiponectin level was elevated by chlorogenic acid supplementation compared to the high-fat control group. Body weight was significantly correlated with plasma leptin (r=0.894, p<0.01) and insulin (r=0.496, p<0.01) levels, respectively. Caffeic acid and chlorogenic acid significantly inhibited fatty acid synthase, 3-hydroxy-3-methylglutaryl CoA reductase and acyl-CoA:cholesterol acyltransferase activities, while they increased fatty acid β-oxidation activity and peroxisome proliferator-activated receptors α expression in the liver compared to the high-fat group. These results suggest that caffeic acid and chlorogenic acid improve body weight, lipid metabolism and obesity-related hormones levels in high-fat fed mice. Chlorogenic acid seemed to be more potent for body weight reduction and regulation of lipid metabolism than caffeic acid.
We investigated the effect of curcumin on insulin resistance and glucose homeostasis in male C57BL/KsJ-db/db mice and their age-matched lean non-diabetic db/+ mice. Both db/+ and db/db mice were fed ...with or without curcumin (0.02%, wt/wt) for 6 wks. Curcumin significantly lowered blood glucose and HbA₁c levels, and it suppressed body weight loss in db/db mice. Curcumin improved homeostasis model assessment of insulin resistance and glucose tolerance, and elevated the plasma insulin level in db/db mice. Hepatic glucokinase activity was significantly higher in the curcumin-supplemented db/db group than in the db/db group, whereas glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities were significantly lower. In db/db mice, curcumin significantly lowered the hepatic activities of fatty acid synthase, β-oxidation, 3-hydroxy-3-methylglutaryl coenzyme reductase, and acyl-CoA: cholesterol acyltransferase. Curcumin significantly lowered plasma free fatty acid, cholesterol, and triglyceride concentrations and increased the hepatic glycogen and skeletal muscle lipoprotein lipase in db/db mice. Curcumin normalized erythrocyte and hepatic antioxidant enzyme activities (superoxide dismutase, catalase, gluthathione peroxidase) in db/db mice that resulted in a significant reduction in lipid peroxidation. However, curcumin showed no effect on the blood glucose, plasma insulin, and glucose regulating enzyme activities in db/+ mice. These results suggest that curcumin seemed to be a potential glucose-lowering agent and antioxidant in type 2 diabetic db/db mice, but had no affect in non-diabetic db/+ mice.
This study investigated the anti-obesity effects of fucoxanthin in diet-induced obesity mice fed a high-fat diet (20% fat, wt/wt). The mice were supplemented with two doses of fucoxanthin (0.05 and ...0.2%, wt/wt) for 6 wk. Fucoxanthin significantly lowered body weight and visceral fat-pads weights compared with the control group without altering food intake. In epididymal adipose tissue of fucoxanthin-fed mice, adipocyte sizes and mRNA expression of lipogenic and fatty acid β-oxidation enzymes were significantly altered in a dose-dependent manner. Plasma leptin level was significantly lower in the fucoxanthin groups than in the control group, while the adiponectin level was elevated. Fucoxanthin significantly down-regulated various lipogenic enzyme activities in epididymal adipose tissue with a simultaneous decrease in fatty acid β-oxidation activity. The 0.2% fucoxanthin supplement led to increase mRNA expression of uncoupling protein-1 (UCP-1) and UCP-3 in brown adipose tissue and that of UCP-2 in the epididymal white adipose tissue. However, the 0.05% fucoxanthin only elevated UCP-1 mRNA expression in epididymal white adipose tissue. These results suggest that the anti-obesity effect of fucoxanthin could be mediated by altering lipid-regulating enzymes and UCPs in the visceral fat tissues and plasma adipokine levels.
Scope
This study investigated the effects of resveratrol (RV) on diabetes‐related metabolic changes in a spontaneous model of type 2 diabetes, as well as activation of AMP‐activated protein kinase ...(AMPK) and downstream targets.
Methods and results
C57BL/KsJ‐db/db mice were fed a normal diet with RV (0.005% and 0.02%, w/w) or rosiglitazone (RG, 0.001%, w/w) for 6 weeks. Both doses of RV significantly decreased blood glucose, plasma free fatty acid, triglyceride, apo B/apo AІ levels and increased plasma adiponectin levels. RV activated AMPK and downstream targets leading to decreased blood HbA1c levels, hepatic gluconeogenic enzyme activity, and hepatic glycogen, while plasma insulin levels, pancreatic insulin protein, and skeletal muscle GLUT4 protein were higher after RV supplementation. The high RV dose also significantly increased hepatic glycolytic gene expression and enzyme activity, along with skeletal muscle glycogen synthase protein expression, similar to RG. Furthermore, RV dose dependently decreased hepatic triglyceride content and phosphorylated I kappa B kinase (p‐IKK) protein expression, while hepatic uncoupling protein (UCP) and skeletal muscle UCP expression were increased.
Conclusion
RV potentiates improving glycemic control, glucose uptake, and dyslipidemia, as well as protecting against pancreatic β‐cell failure in a spontaneous type 2 diabetes model. Dietary RV has potential as an antidiabetic agent via activation of AMPK and its downstream targets.
In this study, a new cathodic catalyst including hemin catalyzing the H
2
O
2
reduction reaction (HPRR) is suggested to improve the performance of flow-type hydrogen peroxide fuel cells (HPFCs). To ...develop the hemin-based catalyst showing excellent HPRR reactivity, buckypaper (BP) and polyethyleneimine (PEI) are used, and it is proved that the final BP/hemin/PEI/hemin catalyst has excellent catalytic activity in terms of current and onset potential for the HPRR. To evaluate the effect of the catalyst on the performance of HPFC, BP/hemin and BP/PEI/hemin catalysts as the control groups are fabricated and compared. When BP/hemin/PEI/hemin is used, the amount of immobilized hemin and the reactivity of the HPRR increase due to the interstitial pores of the carbon nanotube network. Furthermore, its onset potential increases due to the formation of the coordinate bond between the iron core within hemin and the axial ligand within PEI. For preparing membraneless HPFCs, flexible materials such as hemin-modified BP, carbon cloth and polyethylene terephthalate are used, and its open circuit potential and maximum power density are 0.171 ± 0.012 V and 90.7 ± 6.88 μW cm
−2
when 0.1 M H
2
O
2
is injected. These results are far better than those of other previous studies.
In this study, a new cathodic catalyst including hemin catalyzing the H
2
O
2
reduction reaction (HPRR) is suggested to improve the performance of flow-type hydrogen peroxide fuel cells (HPFCs).
Robust mitochondrial respiration provides energy to support physical performance and physiological well-being, whereas mitochondrial malfunction is associated with various pathologies and reduced ...longevity. In the current study, we tested whether myricetin, a natural flavonol with diverse biological activities, may impact mitochondrial function and longevity. The mice were orally administered myricetin (50 mg/kg/day) for 3 weeks. Myricetin significantly potentiated aerobic capacity in mice, as evidenced by their increased running time and distance. The elevated mitochondrial function was associated with induction of genes for oxidative phosphorylation and mitochondrial biogenesis in metabolically active tissues. Importantly, myricetin treatment led to decreased PGC-1α acetylation through SIRT1 activation. Furthermore, myricetin significantly improved the healthspan and lifespan of wild-type, but not Sir-2.1-deficient, C. elegans. These results demonstrate that myricetin enhances mitochondrial activity, possibly by activating PGC-1α and SIRT1, to improve physical endurance, strongly suggesting myricetin as a mitochondria-activating agent.
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