6,448 research outputs found

    Nigella sativa thymoquinone-rich fraction greatly improves plasma antioxidant capacity and expression of antioxidant genes in hypercholesterolemic rats.

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    The antioxidant activities of the thymoquinone-rich fraction (TQRF) extracted from Nigella sativa and its bioactive compound, thymoquinone (TQ), in rats with induced hypercholesterolemia were investigated. Rats were fed a semipurified diet supplemented with 1% (w/w) cholesterol and were treated with TQRF and TQ at dosages ranging from 0.5 to 1.5 g/kg and 20 to 100 mg/kg body wt, respectively, for 8 weeks. The hydroxyl radical (OH ·)-scavenging activity of plasma samples collected from experimental rats was measured by electron spin resonance. The GenomeLab Genetic Analysis System was used to study the molecular mechanism that mediates the antioxidative properties of TQRF and TQ. Plasma total cholesterol and low-density-lipoprotein cholesterol levels were significantly decreased in the TQRF- and TQ-treated rats compared to untreated rats. Feeding rats a 1% cholesterol diet for 8 weeks resulted in a significant decrease in plasma antioxidant capacity, as measured by the capacity to scavenge hydroxyl radicals. However, rats treated with TQRF and TQ at various doses showed significant inhibitory activity toward the formation of OH · compared to untreated rats. Upon examination of liver RNA expression levels, treatment with TQRF and TQ caused the up-regulation of the superoxide dismutase 1 (SOD1), catalase, and glutathione peroxidase 2 (GPX) genes compared to untreated rats (P < 0.05). In support of this, liver antioxidant enzyme levels, including SOD1 and GPX, were also apparently increased in the TQRF- and TQ-treated rats compared to untreated rats (P < 0.05). In conclusion, TQRF and TQ effectively improved the plasma and liver antioxidant capacity and enhanced the expression of liver antioxidant genes of hypercholesterolemic rats

    Assessment of nutritional and mineral composition of different parts of Schismatoglottis bauensis

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    The study was carried out to assess nutritional and mineral composition of dried whole plant, leaf, stem, rhizome and root of Schismatoglottis bauensis. Proximate analysis was carried out by measuring total protein, fats, carbohydrate, ash and moisture contents following official methods of Association of Official Analytical Chemists. Macro- (Ca, Na, K) and micronutrients (Fe, Cu, Zn) were analyzed using atomic absorption spectrometry. Results revealed that dried whole plant showed highest crude fats and moisture content, whilst dried leaf exhibited the highest percentage of crude protein, and dried rhizome had the highest carbohydrate content. The calorific values for whole plant, leaf, stem, rhizome and root were 288.52, 309.19, 267.10, 303.71, and 295.37 Kcal/ 100 g, respectively. Major minerals present in all the tested samples were potassium and calcium ranging from 2714 to 7213 mg/100 g and 216 to 1517 mg/100 g, respectively. Overall, the findings indicate this plant to be a good source of nutrient and minerals, which could be exploited as a valuable material for functional foods or nutraceuticals

    Accelerating universe in two-dimensional noncommutative dilaton cosmology

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    We show that the phase transition from the decelerating universe to the accelerating universe, which is of relevance to the cosmological coincidence problem, is possible in the semiclassically quantized two-dimensional dilaton gravity by taking into account the noncommutative field variables during the finite time. Initially, the quantum-mechanically induced energy from the noncommutativity among the fields makes the early universe decelerate and subsequently the universe is accelerating because the dilaton driven cosmology becomes dominant later.Comment: 14 pages, 2 figures; to appear in Phys. Lett.

    Isolation and antioxidative properties of phenolics-saponins rich fraction from defatted rice bran

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    The study presents a protocol for the preparation of phenolics-saponins rich fraction (PSRF), a new active nutraceutical from defatted rice bran followed by the determination of its antioxidant properties. PSRF was prepared by employing a simple alcoholic fractionation procedure on the crude alcoholic extract (CAE) of defatted rice bran. PSRF was found to be significantly higher in the contents of total phenolic, saponin, and steroidal saponin than CAE and its counterpart, aqueous fraction (AqF) (p < 0.05). Except for iron chelating activity, PSRF exhibited notably higher activity than CAE and AqF in all antioxidant activity assays performed (p < 0.05). HPLC-DAD analysis revealed that PSRF contained substantially higher amounts of gallic acid, 4-hydroxybenzoic acid, caffeic acid, p-coumaric acid, and ferulic acid than CAE and AqF (p < 0.05). In conclusion, alcoholic fractionation of CAE simultaneously concentrated the phenolic compounds and saponins into PSRF, thus contributed to its higher antioxidant activity. Due to its elevated antioxidant properties, PSRF may be recommended for investigation as an active ingredient in the nutraceutical, functional food, and natural food preservative formulations. This is also the first report suggesting defatted rice bran as a potential and sustainable source of saponins

    Zero-field dissipationless chiral edge transport and the nature of dissipation in the quantum anomalous Hall state

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    The quantum anomalous Hall (QAH) effect is predicted to possess, at zero magnetic field, chiral edge channels that conduct spin polarized current without dissipation. While edge channels have been observed in previous experimental studies of the QAH effect, their dissipationless nature at a zero magnetic field has not been convincingly demonstrated. By a comprehensive experimental study of the gate and temperature dependences of local and nonlocal magnetoresistance, we unambiguously establish the dissipationless edge transport. By studying the onset of dissipation, we also identify the origin of dissipative channels and clarify the surprising observation that the critical temperature of the QAH effect is two orders of magnitude smaller than the Curie temperature of ferromagnetism.Comment: main text+supporting materials. This is the accepted version for PRL. Comments are welcom

    Edge effects in electrostatic calibrations for the measurement of the Casimir force

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    We have performed numerical simulations to evaluate the effect on the capacitance of finite size boundaries realistically present in the parallel plane, sphere-plane, and cylinder-plane geometries. The potential impact of edge effects in assessing the accuracy of the parameters obtained in the electrostatic calibrations of Casimir force experiments is then discussed

    Polyphenol-rich ethyl acetate fraction of Molineria latifolia rhizome restores oxidant-antioxidant balance by possible engagement of KEAP1-NRF2 and PKC/NF-κB signalling pathways

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    The present study examined the potential of ethyl acetate fraction (EAF) isolated from Molineria latifolia rhizome to modulate the oxidant-antioxidant balance in high fat diet and nicotinamide/streptozotocin-induced diabetic rats. Administration with EAF ameliorated systemic antioxidant status- and oxidative stress-related parameters without affecting the renal and liver functions in the diabetic rats. Further analyses on adipose, muscle and liver tissues demonstrated differing ability to scavenge free radicals and protection against lipid peroxidation. Transcriptional changes proposed concerted modulation of both KEAP1-NRF2 and PKC/NF-κB signallings in tissue-specific manner. Qualitative profiling of compounds present in EAF was analysed by non-targeted HPLC-QTOF mass spectrometry. A total of 23 unique mass signals were detected in EAF. Putative identification revealed a mixture of naturally occurring polyphenols ranging from cinnamic acid-, benzoic acid- and flavonoid-derived groups. Overall, the study demonstrated potential application of EAF to reinstate diabetes-induced oxidant-antioxidant imbalance by potentially modulating the NRF2–NF-κB signalling axis

    Defatted kenaf seed meal (DKSM) : prospective edible flour from agricultural waste with high antioxidant activity

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    The present study reports nutritional composition, phenolic content and antioxidant activity of defatted kenaf seed meal (DKSM) in comparison to wheat, rice and sweet potato flours. Proximate analysis revealed that DKSM was high in protein (26.19 g/100 g DKSM) and carbohydrate (57.09 g/100 g DKSM). Magnesium, potassium and phosphorus were the major minerals (>1 g/100 g DKSM) found in DKSM through Energy Dispersive X-ray Spectrometric analysis. DKSM also exhibited appreciably higher total phenolic (3399.37 μg gallic acid equivalent (GAE)/g defatted material) and flavonoid contents (251.00 μg rutin equivalent (RE)/g defatted material) as well as antioxidant activity as compared to all selected edible flours (p < 0.05). Gallic acid, (+)-catechin, 4-hydroxybenzoic acid, vanillic acid and syringic acid were determined as the predominant phenolics in DKSM through HPLC–DAD analysis. On the basis of this study, DKSM may be declared and commercialized as a highly antioxidative and nutritive edible flour, which can be prospectively used in the development of natural food preservative, nutraceuticals and functional foods

    Antioxidant activity of phenolics-saponins rich fraction prepared from defatted kenaf seed meal

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    The current study is aimed to determine the antioxidant properties of crude ethanolic extract (CEE) of defatted kenaf seed meal (DKSM) and its derived n-butanol (BF) and aqueous (AqF) fractions. Spectrophotometric assays showed that BF contained the highest amount of phenolic compounds and saponins, followed by CEE and AqF (p < 0.05). Similarly, HPLC-DAD analysis revealed that level of all the detected predominant phenolic compounds was significantly higher in BF (p < 0.05). Through multiple antioxidant assays, BF exhibited higher antioxidant activity than CEE and AqF, except for iron chelating activity (p < 0.05). Antioxidant activity of CEE and fractions were strongly correlated to their phenolic and saponin contents. This study showed that phenolic compounds and saponins could be extracted and partially purified simultaneously from DKSM by employing a simple alcoholic extraction–fractionation procedure. High antioxidative phenolics–saponins rich fraction from DKSM is a potential active ingredient that could be applied in nutraceuticals, functional foods as well as natural food preservatives
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