Recently, research on antioxidants has become increasingly active in various fields. Antioxidants react through free radical or molecular oxygen quenching, being capable to either delay or inhibit ...the oxidation processes that occur under the influence of molecular oxygen or reactive oxygen species. Accordingly, assays developed to evaluate the antioxidant activity of food constituents vary. Therefore, to investigate the antioxidant activity of chemical(s), choosing an adequate assay based on the properties of chemical(s) is critical. Antioxidant assays may be broadly classified as electron transfer (ET)‐based assays and hydrogen atom transfer (HAT)‐based assays. ET‐based assays include ABTS assay, DPPH assay, ferrous oxidation‐xylenol orange assay, ferric thiocyanate assay, ferric reducing/antioxidant power assay, potassium ferricyanide reducing power assay, and cupric reducing antioxidant power assay. HAT‐based assays include oxygen radical absorbance capacity assay, total peroxyl radical‐trapping antioxidant parameter assay, thiobarbituric acid assay, β‐carotene bleaching assay, and cellular antioxidant activity assay. In this guideline, assays used recently were selected for extended discussion, including the mechanisms underlying each assay as well as the practice of antioxidant capacity assessment.
Antioxidant capacity assessment method based on electron transfer (ET) and hydrogen atom transfer (HAT) mechanisms.
A circadian rhythm is any biological activity rhythm driven by internal circadian clocks (∼24 h) and entrained by external signals. Its disruption leads to the development of many diseases, including ...obesity, metabolic syndrome, and cancer. However, not many medical treatments for circadian rhythm disorder has been applied. Several phytochemicals demonstrate the ability to prevent or even treat circadian-related diseases and function as circadian modulators. In this review, we briefly summarize the molecular architecture of circadian rhythm in mammals and circadian-related diseases. The effects of various phytochemicals such as caffeine, quercetin, cinnamic acid, and resveratrol on circadian clocks are highlighted. Potential application of diet therapy for circadian disorder and future research directions are also discussed.
Acteoside has been reported to have antioxidant and neuroprotective effect, which is a promising therapeutic way in prevention and treatment of Parkinson's disease. The present study was aimed to ...understand the neuroprotective effect of acteoside and to elucidate its underlying mechanism. 6-hydroxydopamine (6-OHDA)-induced neural damage in zebrafish model was used to study the protective effect of acteoside on Parkinson's disease (PD). Locomotion behavioral test showed that acteoside could prevent 6-OHDA-stimulated movement disorders. Anti-tyrosine hydroxylase (TH) whole-mount immunostaining analysis showed that acteoside could prevent 6-OHDA-induced dopaminergic neuron death. In addition, pretreatment with acteoside could upregulate antioxidative enzymes by activating the Nrf2/ARE signaling pathway in zebrafish. Meanwhile, acteoside was found to be distributed in the brain after intraperitoneal injection into the adult zebrafish, indicating that this compound could penetrate the blood-brain-barrier (BBB). This study demonstrated that acteoside could penetrate BBB and have potential therapeutic value for PD by activating the Nrf2/ARE signaling pathway and attenuating the oxidative stress.
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•Acteoside showed neuroprotective effect of on 6-OHDA-induced zebrafish PD model.•Acteoside activated the Nrf2/ARE signaling pathway in zebrafish PD model.•Acteoside could penetrate the blood-brain-barrier in zebrafish.
Alzheimer’s disease (AD) is the most common cause of dementia in the elderly. Although its pathogenesis remains unclear, studies have indicated microglia-mediated neuroinflammation playing an ...important role. Phytosterols are a class of natural compounds presented in food, and have anti-inflammatory abilities. Recent studies suggested that phytosterols can traverse the blood-brain barrier and enter the brain, however, it remains largely unknown that whether phytosterols affect neuroinflammation in the AD pathogenesis. Here, we used APPswe/PS1dE9 mice as the animal model of AD, and found that stigmasterol treatment attenuated cognitive deficits, and decreased Aβ42 concentration in cortex and hippocampus. Stigmasterol treatment also suppressed neuroinflammation, by reducing pro-inflammatory cytokine levels and microglia activation. Next, we simulated BV2 cells with Aβ42 oligomers, which induced inflammatory responses of microglia. Stigmasterol protected BV2 cells against Aβ42 oligomers induced inflammation, and mediated secretion of pro-inflammatory cytokines via NF-κB and NLRP3 signaling pathways by AMPK activation. Stigmasterol also alleviated the M1 polarization of BV2 cells. In general, our study demonstrates that stigmasterol ameliorated neuroinflammation in APP/PS1 mice, and suppressed inflammatory response of microglia to Aβ42 oligomers via AMPK/NF-κB and AMPK/NLRP3 signaling, which provides a mechanistic insight for stigmasterol in anti‐inflammation and AD therapy.
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•Stigmasterol ameliorated neuroinflammation in APP/PS1 mice.•Stigmasterol alleviated Aβ42 oligomers induced inflammatory response in BV2 cells.•Stigmasterol suppressed NF-κB and NLRP3 signaling by AMPK activation in BV2 cells.
•The level of total phenolic acids in 6 categories of vegetables were in the following order: flower > root > leafy > stem > bean > fruit.•The leafy, root and stem vegetables were more abundant in ...the kinds of phenolic acids than others.•The level of ferulic acid, isoferulic acid and p-coumaric acid were higher than other phenolic acids in vegetables.•Free soluble phenolic acids were the dominant species in vegetables (P < 0.001), with the exception of stem vegetables (P < 0.027).
This study aimed to establish a precise HPLC-MS approach to determine the concentrations and distribution of major phenolic acids in six categories of vegetables that are commonly consumed in China. We detected 17 phenolic acids within 15 min under optimized conditions. The method showed detection limits varying from 0.008 mg/L to 0.042 mg/L, average recoveries ranging from 71.0% to 110.7%, and a RSD of ≤9.98%. The average concentrations of total phenolic acids followed the order of flower > root > leafy > stem > bean > fruit vegetables. The phenolic acids were more abundant in the leafy, root, and stem vegetables than in the other vegetable samples. Furthermore, the levels of isoferulic acid, p-coumaric acid, and ferulic acid were greater than those of other phenolic acids in the vegetables. Free soluble phenolic acids were the dominant species in all vegetables (P < 0.001), except in the stem vegetables (P < 0.027).
•High TTC was detected in sugarcane.•Phytosterols of different parts of sugarcane were identified by HPLC.•Sugarcane rind contained highest TFC and TPC.•Positive relationship between TFC, TPC and ...antioxidant activity was found.
Antioxidant capacities and phytochemicals such as phenolics, flavonoids, triterpenoids, phytosterols of four parts of two sugarcane cultivars have been characterised. The total triterpenoid content (TTC), total phenolic content (TPC), total flavonoid content (TFC) and total sterol content (TSC) were different among parts and cultivars of sugarcane. The node of both cultivars contained the highest TTC (2096.02 and 1779.66mg ursolic acid/100g DW for green-rind and red-rind sugarcane, respectively). However, the highest TPC, TFC and TSC were found in the rind. Green-rind sugarcane cultivars contained higher TSC than the red-rind sugarcane cultivars in most parts, while opposite trend were found in TPC and TFC. Stigmasterol and β-sitosterol were found as two main phytosterols. Furthermore, TPC and TFC revealed good correlations with DPPH and FRAP. As cultivars and parts could affect phytochemical content, present result may provide a theoretical basis for further exploitation of the health beneficial resources of sugarcane.
Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor against oxidative stress and neurodegenerative disorders. Phenylethanoid glycosides (PhGs; salidroside, acteoside, ...isoacteoside, and echinacoside) exhibit antioxidant and neuroprotective bioactivities. This study was performed to investigate the neuroprotective effect and molecular mechanism of PhGs. PhGs pretreatment significantly suppressed H₂O₂-induced cytotoxicity in PC12 cells by triggering the nuclear translocation of Nrf2 and reversing the downregulated protein expression of heme oxygenase 1 (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1), glutamate cysteine ligase-catalytic subunit (GCLC), and glutamate-cysteine ligase modifier subunit (GCLM). Nrf2 siRNA or HO-1 inhibitor zinc protoporphyrin (ZnPP) reduced the neuroprotective effect. PhGs showed potential interaction with the Nrf2 binding site in Kelch-like ECH-association protein 1 (Keap1). This result may support the hypothesis that PhGs are activators of Nrf2. We demonstrated the potential binding between PhGs and the Keap1-activated Nrf2/ARE pathway, and that PhGs with more glycosides had enhanced effects.
► First time, NIR was used to predict antioxidant activity of bamboo leaf extract. ► Three antioxidant activity indices, specifically DPPH, FRAP, and ABTS, were analysed. ► First time, spectral ...variable selection was used for determining antioxidant activity. ► Four regressions algorithms, specifically PLS, MLR, BP-ANN, and LS-SVM, were compared. ► Good predictive result obtained for DPPH (r=0.863), FRAP (r=0.910) and ABTS (r=0.966).
This study was carried out to evaluate the feasibility of using near infrared (NIR) spectroscopy for determining three antioxidant activity indices of the extract of bamboo leaves (EBL), specifically 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing/antioxidant power (FRAP), and 2,2′-azinobis-(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS). Four different linear and nonlinear regressions tools (i.e. partial least squares (PLS), multiple linear regression (MLR), back-propagation artificial neural network (BP-ANN), and least squares support vector machine (LS-SVM)) were systemically studied and compared in developing the model. Variable selection was first time considered in applying the NIR spectroscopic technique for the determination of antioxidant activity of food or agricultural products. On the basis of these selected optimum wavelengths, the established MLR calibration models provided the coefficients of correlation with a prediction (rpre) of 0.863, 0.910, and 0.966 for DPPH, FARP, and ABTS determinations, respectively. The overall results of this study revealed the potential for use of NIR spectroscopy as an objective and non-destructive method to inspect the antioxidant activity of EBL.
The free and bound phenolic compounds in 10 common Chinese edible flowers were investigated using reversed phase high‐performance liquid chromatography. Their antioxidant capacities were evaluated ...using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging activity, 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) radical‐scavenging activity, oxygen radical absorption capacity (ORAC), ferric reducing antioxidant power (FRAP), and cellular antioxidant activity (CAA). Free factions were more prominent in phenolic content and antioxidant capacity than bound fractions. Paeonia suffruticosa and Flos lonicerae showed the highest total phenolic content (TPC) 235.5 mg chlorogenic acid equivalents/g of dry weight and total flavonoid content 89.38 mg rutin equivalents/g of dry weight. The major phenolic compounds identified were gallic acid, chlorogenic acid, and rutin. P. suffruticosa had the highest antioxidant capacity in the DPPH, ABTS, and ORAC assays, which were 1028, 2065, 990 μmol Trolox equivalents/g of dry weight, respectively, whereas Rosa chinensis had the highest FRAP value (2645 μmol Fe²⁺ equivalents /g of dry weight). The P. suffruticosa soluble phenolics had the highest CAA, with the median effective dose (EC₅₀) 26.7 and 153 μmol quercetin equivalents/100 g of dry weight in the phosphate buffered saline (PBS) and no PBS wash protocol, respectively. TPC was strongly correlated with antioxidant capacity (R = 0.8443 to 0.9978, P < 0.01), which indicated that phenolics were the major contributors to the antioxidant activity of the selected edible flowers.
Flavone glycosides, their aglycones, and metabolites are the major phytochemicals in dietary intake. However, there are still many unknowns about the cellular utilization and active sites of these ...natural products. Uridine diphosphate glucuronosyltransferases (UGTs) in the endoplasmic reticulum have gene polymorphism distribution in the population and widely mediate the absorption and metabolism of endogenous and exogenous compounds by catalyzing the covalent addition of glucuronic acid and various lipophilic chemicals. Firstly, we found that rutin, a typical flavone
-glycoside, has a stronger UGT2B7 binding effect than its metabolites. After testing a larger number of flavonoids with different aglycones, their aglycones, and metabolites, we demonstrated that typical dietary flavone
-glycosides generally have high binding affinities towards UGT2B7 protein, but the flavone
-glycosides and the phenolic acid metabolites of flavones had no significant effect on this. With the disposition of 4-methylumbelliferone examined by HPLC assay, we determined that 10 μM rutin and nicotifiorin could significantly inhibit the activity of recombinant UGT2B7 protein, which is stronger than isovitexin, vitexin, 3-hydroxyphenylacetic acid and 3,4-dihydroxyphenylacetic acid. In addition, in vitro experiments showed that in normal and doxorubicin-induced lipid composition, both flavone
-glycosides rutin and flavone
-glycosides isovitexin at 10 μM had no significant effect on the expression of
,
,
, and
genes for 24 h exposure. The obtained results enrich the regulatory properties of dietary flavone glycosides, aglycones, and metabolites towards the catalysis of UGTs and will contribute to the establishment of a precise nutritional intervention system based on lipid bilayers and theories of nutrients on endoplasmic reticulum and mitochondria communication.
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