Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has ...Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity enhancement.Here,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is reported.The substituting Fe content influences both current change tendency and surface reconstruction degree.LaNi_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)series.The reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based catalysts.Besides,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term stability.Furthermore,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree.The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction.This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.展开更多
Oxidative-exfoliation methods were in vogue in the production of rGO from graphite.Processing of such synthetic graphite needs high temperatures(2500℃).Thus,such process is not cost-effective.The present study is mad...Oxidative-exfoliation methods were in vogue in the production of rGO from graphite.Processing of such synthetic graphite needs high temperatures(2500℃).Thus,such process is not cost-effective.The present study is made on the dry leaves of sugarcane(Saccharum officinarum)as an alternative raw material so as to be economical and environmentally benign.The dry leaves are subjected to two-step pyrolysis without any catalyst or reducing agent in far divergent temperatures to produce as prepared and acid treated rGOs.They were evaluated by UV–Vis.,FTIR,XRD,Raman spectroscopy,TGA/DTG,BET,FESEM-EDS and TEM.The as prepared rGO has few layers with irregular and folded architecture whereas acid-treated rGO has thinly stacked crumpled sheets with many wrinkles on its surface.The prepared rGOs have multilayered graphitic structure due to the unique ratio between G and D bands.Acid treated rGO has poor thermal stability as compared to that of as-prepared rGO at high temperatures due to the variation in the oxygen-containing functional groups.Acid treated rGO has low antibacterial activity as compared to that of the as-prepared rGO due to the paucity of the functional groups.展开更多
The aim of the present work is to assess the value of Detarium Senegalense by determining the content of total phenols, total flavonoids and total anthocyanins, and by evaluating the free radical scavenging activity o...The aim of the present work is to assess the value of Detarium Senegalense by determining the content of total phenols, total flavonoids and total anthocyanins, and by evaluating the free radical scavenging activity of Detarium Senegalense extracts. For this purpose, sequential extraction using solvents of increasing polarity was essential. The various extracts obtained underwent phytochemical and biochemical analyses. Phytochemical screening revealed the presence of flavonoids, alkaloids, tannins, polyphenols, anthocyanins and steroids/terpenes. Quantitative analysis of total polyphenols, total flavonoids and total anthocyanins yielded the following results: total flavonoids (0.803 ± 0029 mg EQ/100g P for acetone extract of roots and 0.871 ± 0.401 mg EQ/100g P for methanol extract of leaves);total polyphenols (23.298 ± 12.68 mg EAG/100g P for acetone extract of roots and 24.69 ± 0.49 401 mg EAG/100g P for methanol extract of leaves);total monomeric anthocyanins (44.697 ± 0.939 mg EC3G/100g P and 16.699 ± 0.193 mg EC3G/100g P respectively for acetone and methanol extracts of stem bark). DPPH free radical scavenging activity was 1.674 ± 0.023 mg/mL for the acetone extract and 0.934 ± 0.24 mg/mL for the methanol extract of roots. .展开更多
Objective: To study the blood pressure lowering effect of Cassytha filiformis extract in animal models of hypertension and its correlation with the antioxidant activity.Methods: Male Sprague–Dawley rats were divided ...Objective: To study the blood pressure lowering effect of Cassytha filiformis extract in animal models of hypertension and its correlation with the antioxidant activity.Methods: Male Sprague–Dawley rats were divided into two groups: endocrine hypertension(HTN group) that received a combination of prednisone and salt for two weeks and oxidative stress-associated hypertension(HTN-OS group) that received additional induction of L-Nitro Arginine Methyl Esther(L-NAME) for two days. Each group was subdivided into 4 and treated intravenously with the extract 5; 10; and 20 mg/kg, and vehicle control. The systolic blood pressure(SBP), diastolic blood pressure(DBP), and mean arterial pressure(MAP) were recorded. The blood was taken before and at the end of recording for the measurement of serum concentration of nitric oxide(NO). The changes of blood pressure were analyzed by two-way ANOVA while its correlation with NO concentration was analyzed by Pearson's Correlation.Results: The study showed a significant antihypertensive effect of the extract as compared with control group(P < 0.05) in both hypertensive models. Extract in the dose of 5 mg/kg showed the best blood pressure lowering effect. However, the correlation analysis did not show an association between NO increase and blood pressure lowering effect(P > 0.05).Conclusions: The study concludes that C. filiformis extract in the dose of 5 mg/kg exhibits the best blood pressure lowering effect in both animal models. Antihypertensive activity of the extract is not correlated with its antioxidant effect.展开更多
We investigated the influence of different content of Zn^2＋（0, 2, 4, 8, 16 mmol·kg^-1） on plant growth, activities of peroxidase （POD） and superoxide dismutase （SOD）, free proline content and Zn accumulati...We investigated the influence of different content of Zn^2＋（0, 2, 4, 8, 16 mmol·kg^-1） on plant growth, activities of peroxidase （POD） and superoxide dismutase （SOD）, free proline content and Zn accumulation in four varieties of ryegrass （Loliurn perenne L.） hy pot cuhure experiment. The results showed that plant hiomass increased at the ranges of 0-2 （Tuoya）, 0-4 （Yey- ing）, 0-8 mmol·kg^-1（Airuisi and Taide）, respectively, and then decreased under excess Zn. The activities of POD ,SOD and proline content in shoots decreased firstly, and then increased with the in crease of Zn content. The plaut biomass, activities of POD and SOD in Taide were evidently higher than in the other three varie ties. Root tolerance index （RTI） and Zn transport ratio from root to shoot （S/R） in Taide were exceed 1. 0. The maximum of Zn content was 583.9 mg/kg （ at 16 mmol·kg^-1） in Taide＇s shoot.展开更多
Objective:To evaluate and compare the antioxidant potential and anti-inflammatory activity of ethanolic extract of flowers of Moringa oleifera(M.oleifera)grown in Oman.Methods:Flowers of M.oleiferawere collected in th...Objective:To evaluate and compare the antioxidant potential and anti-inflammatory activity of ethanolic extract of flowers of Moringa oleifera(M.oleifera)grown in Oman.Methods:Flowers of M.oleiferawere collected in the month of December 2012 and identified by a botanist.Alcoholic extract of the dry pulverized flowers ofM.oleiferawere obtained by cold maceration method.The ethanolic flower extract was subjected to preliminary phytochemical screening as the reported methods.Folin-Ciocalteu reagent was used to estimate total phenolic content.DPPH was used to determinein-vitroantioxidant activity and anti-inflammatory activity of flowers was investigated by protein denaturation method.Results:Phytochemical analysis of extract showed presence of major classes of phytochemicals such as tannins,alkaloids,flavonoids,cardiac glycosidesetc.M.oleiferaflowers were found to contain 19.31 mg/g of gallic acid equivalent of total phenolics in dry extract but exhibited moderate antioxidant activity.The anti-inflammatory activity of plant extract was significant and comparable with the standard drug diclofenac sodium.Conclusions:The results of our study suggest that flowers ofM.oleiferapossess potent anti-inflammatory activity and are also a good source of natural antioxidants.Further study is needed to identify the chemical compounds responsible for their anti-inflammatory activity.展开更多
Dietary intake of 0.1% fucoxanthin significantly reduced lipid hydroperoxide levels of liver and abdominal white adipose tissue (WAT) of obese/diabetes KK-Ay mice. The fucoxanthin supplementation also significantly re...Dietary intake of 0.1% fucoxanthin significantly reduced lipid hydroperoxide levels of liver and abdominal white adipose tissue (WAT) of obese/diabetes KK-Ay mice. The fucoxanthin supplementation also significantly reduced blood glucose level and hepatic lipid contents of the mice. Oxidative stress is known to be induced in hyperglycemia and high fat conditions. Therefore, in vivo antioxidant activity of fucoxanthin found in the present study could be attributed to its anti-diabetic effect and its decreasing effect on hepatic lipids. On the other hand, little effect of fucoxanthin on lipid hydroperoxide levels was found in normal ICR mice. Although the content of fucoxanthin metabolites in the abdominal WAT of KK-Ay mice was about 50 times higher that in the liver, there was little difference in its In Vivo antioxidant activity between in the liver and in the abdominal WAT. These results suggest that well-known ability of fucoxanthin to scavenge active oxygen species and/or free radicals would not be a main reason to explain its In Vivo antioxidant activity.展开更多
Objective:To investigate the antioxidant and anti-inflammatory activity of orally administered methanolic leaf extract of Dalbergia paniculala(D.paniculata) in Carrageenan induced inflammation in rats.Methods:In vitro...Objective:To investigate the antioxidant and anti-inflammatory activity of orally administered methanolic leaf extract of Dalbergia paniculala(D.paniculata) in Carrageenan induced inflammation in rats.Methods:In vitro antioxidant activity was evaluated for superoxide radical, Hydroxyl radical and DPPH radical scavenging activity.Three doses 200 mg/kg,400 mg/kg and 800 mg/kg of D.paniculala were tested for anti-inflammatory activity in Carrageenan induced rat paw edema model and paw thickness was measured every one hour up to 6 h. Results:The melhanolic leaf extract of D.paniculala produced dose dependent inhibition of Superoxide radical,Hydroxyl radical and OPPH radicals.In Carrageenan induced inflammation model,all three doses produced significant percentage inhibition of rat paw edema and 800 mg/kg dose produced maximum percent inhibition of rat paw edema(47.83%) at 3h compared to control group.Conclusions:In the present study we found that methanolic leaf extract of D.paniculata showed good in vitro antioxidant activity and in vivo anti-inflammatory activity in rats.展开更多
The anthocyanin pigment extracted from green-wheat-bran was studied to identify its antioxidant activity.The antioxidant activities of the pigment were evaluated by anti-lipid peroxidation,total antioxidant activity ...The anthocyanin pigment extracted from green-wheat-bran was studied to identify its antioxidant activity.The antioxidant activities of the pigment were evaluated by anti-lipid peroxidation,total antioxidant activity （TAA）,superoxide anion radical scavenging activity （SARSA）,active oxygen scavenging activity （AOSA）,and DPPH （1,1-diphenyl-2 picrylhydrazyl free radical） radical scavenging activity.The results showed that the pigment had higher antioxidant activity and TAA,SARSA,AOSA and DPPH.scavenging activities at a certain concentration than Vc （antiscorbutic vitamin,vitamin C）,and the capacity increased with the increase of pigment concentration.Its TAA was 51.06 U mL-1,1.73 times of Vc,and SARSA 18 025.21 U mL-1,2.26% higher than Vc,and AOSA 3 776.31 U mL-1,1.24 times of Vc.As to the DPPH.scavenging activity of the pigment,there was a trend that higher concentration performed higher activity significantly improved with the company of Vc.The pigment showed significant antioxidant activities evaluated by different assays.Results will provide a better understanding on antioxidant activity of green wheat and allow the screening or breeding of green wheat varieties with higher antioxidant activity for food processing.展开更多
Flavonoids have attracted considerable attention due to their health benefits. This study aimed to investigate the flavonoid profiles and antioxidant activity of Paeonia lactiflora petal flavonoid extract(PPF). The UH...Flavonoids have attracted considerable attention due to their health benefits. This study aimed to investigate the flavonoid profiles and antioxidant activity of Paeonia lactiflora petal flavonoid extract(PPF). The UHPLC-ESI-Q-Exactive HF MS/MS method was established for characterization, and 21 predominant flavonoid compounds were tentatively identified in PPF. Among them, isoscutellarein-7-(6’-acetylallosyl-(1->2)-glucoside) and scutellarin methylester were discovered in PPF for the first time. Pretreatment with PPF significantly reduced H2O2-induced cell damage, ROS accumulation, and malondialdehyde content and increased the activity of SOD, CAT, and GSH-Px in buffalo rat liver 3A(BRL3A) cells. Moreover, the expression of nuclear Factor E2-related factor(Nrf2) was upregulated by PPF, whose expression trend was consistent with that of heme oxygenase-1(HO-1), glutamate-cysteine ligase catalytic subunit(GCLC), and NAD(P)H quinone oxidoreductase-1(NQO1). These findings suggested that herbaceous peony flavonoids can be used as a natural bioactive agent to prevent oxidative stress.展开更多
In this study the antioxidant activity of barley malt rootlet (BMR) extracts w</span><span style="font-family:"">as</span><span style="font-family:""> evaluated in...In this study the antioxidant activity of barley malt rootlet (BMR) extracts w</span><span style="font-family:"">as</span><span style="font-family:""> evaluated in heat treated corn oil up to 5 hours at 185</span><span style="font-family:"">°</span><span style="font-family:"">C frying temperature. The antioxidant activity </span><span style="font-family:"">of </span><span style="font-family:"">BMR extracts was measured at 25, 50, 100 and 150 ppm concentrations. The free and bound antioxidant phenolics were extracted from BMR using three different extraction methods. Conventional solvent extraction (CSE), microwave assisted extraction (MAE) and autoclave assisted pretreated solvent extraction (APSE). In the present experiment, the total phenolic content and antioxidant activity of the various extracts w</span><span style="font-family:"">ere</span><span style="font-family:""> measured. Thiobarbituric acid reactive substances (TBARS) assay was used to evaluate the ability of the BMR to protect lipid peroxidation in corn oil at 185</span><span style="font-family:"">°</span><span style="font-family:"">C frying temperature. The formation of TBARS at 5 hours of heat treated corn oil ha</span><span style="font-family:"">s</span><span style="font-family:""> shown similar antioxidant levels in 150 ppm butylated hydroxytoluene (BHT) or MAE free phenolic extract added to corn oil. TBARS value for BHT was 1.896 ± 0.013 μg/mL of corn oil and for MAE was 1.896 ± 0.034 μg/mL of corn oil. The highest level of antioxidant activity was found for the free phenolic extracts. The order of inhibition of oxidation was found to be for free phenolics as follows: BHT (100 ppm) > APSE (50 ppm) > MAE (100 ppm) > CSE (100 ppm).展开更多
Oxidative stress plays a key role in the pathogenesis of various diseases.Nature antioxidants derived from traditional Chinese medicine protect the cells and tissues from oxidative stress by scavenging free radicals a...Oxidative stress plays a key role in the pathogenesis of various diseases.Nature antioxidants derived from traditional Chinese medicine protect the cells and tissues from oxidative stress by scavenging free radicals and reactive oxygen species,therefore have a great potential in delaying ageing process and preventing oxidative stress-related disease.In this article,the antioxidant benefits of common single and compound traditional Chinese medicine in protecting tissues from injury are reviewed,along with identification of the various constituents that possess antioxidant activity and its mechanism were reviewed.展开更多
Objective: In this study, we plan to measure plasma Catalase (CAT), Antioxidant Activity (AOA) and Glu- tathione-S-Transferase (GST) levels to understand whether oxidative stress develops or not and whether or not the...Objective: In this study, we plan to measure plasma Catalase (CAT), Antioxidant Activity (AOA) and Glu- tathione-S-Transferase (GST) levels to understand whether oxidative stress develops or not and whether or not the detoxification mechanism properly functions in children with Attention Deficit and Hyperactivity Disorder (ADHD) with unknown etiology and pathogenesis. Method and Results: Plasma CAT, AOA, and GST activities were spectrophotometrically measured in forty patients (average age 10.27 ± 2.54) and thirty-five (average age, 9.97 ± 2.59) healthy individuals as the control group. While the CAT activity showed no difference in the patient group (P > 0.05) compared to the control group, AOA and GST levels were found significantly meaningful (P = 0.001). Conclusion: In this pilot study ,the study shows that no oxidative stress develops in individuals with ADHD in high AOA and stable CAT activity, and that the de- toxification mechanism functions extremely in high GST activity. These findings need to be supported by other studies.展开更多
Objective: To investigate L-3, 4-dihydroxyphenylalanine(L-dopa, anti-Parkinson drug),anti-inflammatory activity, proximate nutritional composition and antioxidant potential of Mucuna macrocarpa(M. macrocarpa) beans.Me...Objective: To investigate L-3, 4-dihydroxyphenylalanine(L-dopa, anti-Parkinson drug),anti-inflammatory activity, proximate nutritional composition and antioxidant potential of Mucuna macrocarpa(M. macrocarpa) beans.Methods: L-dopa content was determined and quantified by high performance thin layer chromatography and reversed phase high-performance liquid chromatography(RPHPLC) methods. Anti-inflammatory activity was performed by in vitro protein denaturation inhibition and human red blood cell membrane stabilisation activity. Proximate composition and elemental analysis were also investigated. The antioxidant potential(2,2-diphenyl-1-picrylhydrazyl, N-N-dimethyl-phenylenediamine and ferric-reducing antioxidant power) of M. macrocarpa beans were evaluated by using different extraction solvents. The RP-HPLC analysis also quantified significant phenolics such as gallic acid, tannic acid, p-hydroxybenzoic acid and p-coumaric acid.Results: RP-HPLC quantification revealed that M. macrocarpa beans contain a high level of L-dopa [(115.41 ± 0.985) mg/g] which was the highest among the Mucuna species from Indian sub-continent. Water extract of seed powder showed strong antiinflammatory and antioxidant potential. Proximate composition of M. macrocarpa beans revealed numerous nutritional and anti-nutritional components. RP-HPLC analysis of major phenolics such as tannic acid(43.795 mg/g), gallic acid(0.864 mg/g), p-coumaric acid(0.364 mg/g) and p-hydroxybenzoic acid(0.036 mg/g) quantified successfully from M. macrocarpa beans respectively.Conclusions: This study suggests that M. macrocarpa is a potential source of L-dopa with promising anti-inflammatory, antioxidant and nutritional benefits.展开更多
Super oxide anion had been known as a critical role in a phagocytic cell when microorganisms invade inside. However, this radical seldom need for a clean environment such in a developed country. Moreover, this agent s...Super oxide anion had been known as a critical role in a phagocytic cell when microorganisms invade inside. However, this radical seldom need for a clean environment such in a developed country. Moreover, this agent sometimes triggered as serious factor in the site of inflammation. There are many papers which concerned newly found anti-oxidative substances. However, many reports only focused on the molecular basis in vitro, how oxidative stress damaged the human tissue. The key factor for oxidative stress needs to be discussed first for immunological standpoint, such as armed reduction treaty. In other words, minimum armed force is necessary for an invasion by outer or inner irregular cells. On the basis of phagocytic function of the cell in vivo, we tried to access anti-oxidative activity by employing peritoneal murine macrophage and human monocyte. So, the purpose of this study is to establish a conventional but tailor made system for which is useful for evaluating the anti-oxidative activity to different constition. Especially in human peripheral monocyte, the sample was tested each constitution such in granulocyte rich type and lymphocyte rich typ. In order to establish the direct estimation by phagocytic cell, a murine peritoneal exudates cell suspension was obtained after one week of oral administration with anti-oxidative sample. The samples we selected were traditional Chinese medicine, Shi-Quan-Da-Bu-Tang (SDT), Bu-Zong-Ye-Qi-Tang (BYT) and Shao-Chin-Rong-Tang sCRT), Agaricus, Chlorella, and Propolis. The amount of generated super oxide anion was calculated through measuring the optical density change of this supernatant using cytochrome-C which was reduced by generated super oxide anion in the phagocytic cell. The generated super oxide anion after administration of Agaricus, Chlorella, SDT, BYT, sCRT and Propolis were 2.64, 1.95, 1.24, 1.25, 2.88, 2.55 × 10﹣5 mmol/ml, respectively, whereas 2.85 × 10﹣5 mmol/ml in control group. The fermented sample from SDT, BYT, sCRT and microfied Propolis were also tested and the value of super oxide anion were 0.62, 0.84, 1.50 and 2.55 × 10﹣5 mmol/ml, respectively. In this report, we discussed the direct method for measuring the generated super oxide anion of macrophages, especially from different constitution.展开更多
Soybeans are known as a promising source of bioactive peptides.However,knowledge on the antioxidant behaviors of soybean protein hydrolysate(SPH)in the human intestinal epithelium is limited.In this study,SPH was prep...Soybeans are known as a promising source of bioactive peptides.However,knowledge on the antioxidant behaviors of soybean protein hydrolysate(SPH)in the human intestinal epithelium is limited.In this study,SPH was prepared with Alcalase and subsequently ultrafiltered into four peptide fractions as SPH-I(<3 kDa),SPH-II(3~5 k Da),SPH-III(5~10 k Da)and SPH-IV(>10 kDa).The antioxidant properties of SPH and membrane fractions were investigated using different chemical assays and their protective effects against oxidative stress were evaluated using H2 O2-stressed human intestinal Caco-2 cells.Results showed that SPH-I exhibited the strongest 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging activity(IC50=2.56 mg/m L)and reducing capacity while SPH-III had the best metal ion-chelating activity(IC50=0.29 mg/m L).Both SPH and the peptide fractions dose-dependently suppressed intracellular reactive oxygen species(ROS)accumulation induced by H2O2 in Caco-2 cells,but the strongest inhibitory effect was observed for SPH-I.Amino acid(AA)results revealed that SPH-I was rich in hydrophobic and antioxidant AAs,which could contribute to its stronger antioxidant properties.Additionally,SPH-I protected Caco-2 cells from H2O2-induced oxidative stress via inhibiting lipid peroxidation and stimulating antioxidant enzyme activities.These results suggest that SPH-I and constitutive peptides can be beneficial ingredients with antioxidant properties and protective effects against ROS-mediated intestinal injury.展开更多
Carbonic anhydrase isozyme CA3 protects cells against oxidative stress. Ectopic expression of murine Ca3, but not Ca2, protects proto-oncogene Evi1 expressing Rat1 fibroblast cells (ca3low) against hydrogen peroxide (...Carbonic anhydrase isozyme CA3 protects cells against oxidative stress. Ectopic expression of murine Ca3, but not Ca2, protects proto-oncogene Evi1 expressing Rat1 fibroblast cells (ca3low) against hydrogen peroxide (H2O2) induced stress. Ca3 is S-glutathionylated via glutathione adducts with cysteines 181 and 186. Substitution of both Ca3 cysteines with serine fails to protect cells from oxidative stress. Insertion of cysteine at 181 and 186 in Ca2 is insufficient for conferring efficient anti-oxidant activity. This shows for the first time that S-glutathionylation of cys181 and cys186 residues is required for Ca3 anti-oxidant activity but that additional factors are also required.展开更多
The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 oC have been studied. The followin...The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 oC have been studied. The following flavonoids;quercetin, rutin and morin significantly protected eryt-hrocytes against lipid peroxidation caused by H2O2. This inhibition of lipid peroxidation could be explained by the presence of at least two hydroxyl groups in ring B of the flavonoid structure, regardless of their positions. However, the flavonoids;quercetin, 3,5,7-trihy- droxy-4'-methoxy flavone-7-rutinoside and 3- hydroxy flavone significantly protected eryt-hrocytes against protein degradation. This inhibition could also be explained by the presence of a hydroxyl group at C-3 in ring C of the flavonoid structure. Quercetin and 3,5,7-trihydroxy-4'- methoxy flvone-7-rutinoside significantly protected erythrocytes against loss of deformability and increased osmotic fragility, indicating that the loss of erythrocyte deformability and the increase in osmotic fragility of erythrocytes exposed to H2O2 are related to protein degradation rather than to lipid peroxidation. The other flavonoids (chrysin, 2-carboxy ethyl dihydroxy flavone, apigenin, cirsimaritin, α-naphto flavone and flavanone) failed to protect erythrocytes against the observed oxidative damages. The results demonstrate the importance of the chemical groups substituted on the basic skeleton of the flavonoids in dictating the type of antioxidant activity, and also demonstrate the hemorheological potentials of flavonoids that have particular protein-antioxidant activities.展开更多
From the ethyl acetate extract of the medicinal plant Graptophyllum glandulosum Turrill, five known compounds: Lupeol (1), Oleanolic acid (2), Chrysoeriol (3), N-methyl-isonicotinamide (4) and β-sitosterol 3-O-β-D-g...From the ethyl acetate extract of the medicinal plant Graptophyllum glandulosum Turrill, five known compounds: Lupeol (1), Oleanolic acid (2), Chrysoeriol (3), N-methyl-isonicotinamide (4) and β-sitosterol 3-O-β-D-glucopyranoside (5) were isolated. In addition, oxidation reactions carried out on lupeol (1) yielded two semi-synthetic compounds, including a previously unreported: (20R)-formyloxy-29-nor-lupan-3-one (1b) and one other well-known Lupenone (1a). The structures of natural and semi-synthetic compounds were determined by analysis of 1D-(1H, 13C), 2D-(COSY, HSQC and HMBC) NMR data in conjunction with mass spectrometry (TOFESIMS and HR-TOFESIMS) and by comparison with the reported data. The evaluation of antimicrobial activities of substrate (1) as well as semi-synthetic derivatives (1a and 1b) using broth microdilution method showed that compound 1b was the most active (16 ≤ MIC ≤ 32 μg/mL) against Escherichia coli, Staphylococcus aureus and Candida albicans compared to the starting material 1 (16 ≤ MIC ≤ 64 μg/mL) and derivative 1a (32 ≤ MIC ≤ 64 μg/mL).展开更多
Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculate...Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculated using DMol3,since HMX and O are key substances in decomposition process.And the relationship between the adsorption energy of HMX,O on metal oxides(TiO_(2),Al_(2)O_(3),PbO,CuO,Fe_(2)O_(3),Co_(3)O_(4),Bi_(2)O_(3),NiO)and experimental T30 values(time required for the decomposition depth of HMX to reach 30%)was depicted as volcano plot.Thus,the T30 values of other metal oxides was predicted based on their adsorption energy on volcano plot and validated by previous experimental data.Further,the adsorption energy of HMX on ZrO_(2)and MnO_(2)was predicted based on the linear relationship between surface energy and adsorption energy,and T30 values were estimated based on volcano plot.The apparent activation energy data of HMX/MgO,HMX/SnO_(2),HMX/ZrO_(2),and HMX/MnO_(2)obtained from DSC experiments are basically consistent with our predicted T30 values,indicating that it is feasible to predict the catalytic activity based on the adsorption calculation,and it is expected that these simple structural properties can predict adsorption energy to reduce the large quantities of computation and experiment cost.展开更多
基金funded by the National Key R&D Program of China(2021YFA1501101)the National Natural Science Foundation of China(No.22471103,22425105,22201111,21931001,22221001,and 22271124)+5 种基金Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the Special Fund Project of Guiding Scientific and Technological Innovation Development of Gansu Province(2019ZX-04)the 111 Project(B20027)as well as the National Natural Science Foundation of Gansu Province(22JR5RA470)the Fundamental Research Funds for the Central Universities(lzujbky-2023-eyt03)supported by the Agency for Science,Technology and Research(A*STAR)MTC Individual Research Grants(IRG)M22K2c0078.
文摘Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity enhancement.Here,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is reported.The substituting Fe content influences both current change tendency and surface reconstruction degree.LaNi_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)series.The reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based catalysts.Besides,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term stability.Furthermore,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree.The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction.This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.
文摘Oxidative-exfoliation methods were in vogue in the production of rGO from graphite.Processing of such synthetic graphite needs high temperatures(2500℃).Thus,such process is not cost-effective.The present study is made on the dry leaves of sugarcane(Saccharum officinarum)as an alternative raw material so as to be economical and environmentally benign.The dry leaves are subjected to two-step pyrolysis without any catalyst or reducing agent in far divergent temperatures to produce as prepared and acid treated rGOs.They were evaluated by UV–Vis.,FTIR,XRD,Raman spectroscopy,TGA/DTG,BET,FESEM-EDS and TEM.The as prepared rGO has few layers with irregular and folded architecture whereas acid-treated rGO has thinly stacked crumpled sheets with many wrinkles on its surface.The prepared rGOs have multilayered graphitic structure due to the unique ratio between G and D bands.Acid treated rGO has poor thermal stability as compared to that of as-prepared rGO at high temperatures due to the variation in the oxygen-containing functional groups.Acid treated rGO has low antibacterial activity as compared to that of the as-prepared rGO due to the paucity of the functional groups.
文摘The aim of the present work is to assess the value of Detarium Senegalense by determining the content of total phenols, total flavonoids and total anthocyanins, and by evaluating the free radical scavenging activity of Detarium Senegalense extracts. For this purpose, sequential extraction using solvents of increasing polarity was essential. The various extracts obtained underwent phytochemical and biochemical analyses. Phytochemical screening revealed the presence of flavonoids, alkaloids, tannins, polyphenols, anthocyanins and steroids/terpenes. Quantitative analysis of total polyphenols, total flavonoids and total anthocyanins yielded the following results: total flavonoids (0.803 ± 0029 mg EQ/100g P for acetone extract of roots and 0.871 ± 0.401 mg EQ/100g P for methanol extract of leaves);total polyphenols (23.298 ± 12.68 mg EAG/100g P for acetone extract of roots and 24.69 ± 0.49 401 mg EAG/100g P for methanol extract of leaves);total monomeric anthocyanins (44.697 ± 0.939 mg EC3G/100g P and 16.699 ± 0.193 mg EC3G/100g P respectively for acetone and methanol extracts of stem bark). DPPH free radical scavenging activity was 1.674 ± 0.023 mg/mL for the acetone extract and 0.934 ± 0.24 mg/mL for the methanol extract of roots. .
基金financially supported by Ministry of National Education and Culture, The Republic of Indonesia under the scheme of Fundamental Research [grant number 02/UN.16/PLFD/2013]
文摘Objective: To study the blood pressure lowering effect of Cassytha filiformis extract in animal models of hypertension and its correlation with the antioxidant activity.Methods: Male Sprague–Dawley rats were divided into two groups: endocrine hypertension(HTN group) that received a combination of prednisone and salt for two weeks and oxidative stress-associated hypertension(HTN-OS group) that received additional induction of L-Nitro Arginine Methyl Esther(L-NAME) for two days. Each group was subdivided into 4 and treated intravenously with the extract 5; 10; and 20 mg/kg, and vehicle control. The systolic blood pressure(SBP), diastolic blood pressure(DBP), and mean arterial pressure(MAP) were recorded. The blood was taken before and at the end of recording for the measurement of serum concentration of nitric oxide(NO). The changes of blood pressure were analyzed by two-way ANOVA while its correlation with NO concentration was analyzed by Pearson's Correlation.Results: The study showed a significant antihypertensive effect of the extract as compared with control group(P < 0.05) in both hypertensive models. Extract in the dose of 5 mg/kg showed the best blood pressure lowering effect. However, the correlation analysis did not show an association between NO increase and blood pressure lowering effect(P > 0.05).Conclusions: The study concludes that C. filiformis extract in the dose of 5 mg/kg exhibits the best blood pressure lowering effect in both animal models. Antihypertensive activity of the extract is not correlated with its antioxidant effect.
基金Supported by the National Natural Science Foundation ofChina (29877021)
文摘We investigated the influence of different content of Zn^2＋（0, 2, 4, 8, 16 mmol·kg^-1） on plant growth, activities of peroxidase （POD） and superoxide dismutase （SOD）, free proline content and Zn accumulation in four varieties of ryegrass （Loliurn perenne L.） hy pot cuhure experiment. The results showed that plant hiomass increased at the ranges of 0-2 （Tuoya）, 0-4 （Yey- ing）, 0-8 mmol·kg^-1（Airuisi and Taide）, respectively, and then decreased under excess Zn. The activities of POD ,SOD and proline content in shoots decreased firstly, and then increased with the in crease of Zn content. The plaut biomass, activities of POD and SOD in Taide were evidently higher than in the other three varie ties. Root tolerance index （RTI） and Zn transport ratio from root to shoot （S/R） in Taide were exceed 1. 0. The maximum of Zn content was 583.9 mg/kg （ at 16 mmol·kg^-1） in Taide＇s shoot.
基金Supported by the Department of Pharmacy,Oman Medical College,Muscat,Oman(Grant No.OMC-PHAR/425-08/12)
文摘Objective:To evaluate and compare the antioxidant potential and anti-inflammatory activity of ethanolic extract of flowers of Moringa oleifera(M.oleifera)grown in Oman.Methods:Flowers of M.oleiferawere collected in the month of December 2012 and identified by a botanist.Alcoholic extract of the dry pulverized flowers ofM.oleiferawere obtained by cold maceration method.The ethanolic flower extract was subjected to preliminary phytochemical screening as the reported methods.Folin-Ciocalteu reagent was used to estimate total phenolic content.DPPH was used to determinein-vitroantioxidant activity and anti-inflammatory activity of flowers was investigated by protein denaturation method.Results:Phytochemical analysis of extract showed presence of major classes of phytochemicals such as tannins,alkaloids,flavonoids,cardiac glycosidesetc.M.oleiferaflowers were found to contain 19.31 mg/g of gallic acid equivalent of total phenolics in dry extract but exhibited moderate antioxidant activity.The anti-inflammatory activity of plant extract was significant and comparable with the standard drug diclofenac sodium.Conclusions:The results of our study suggest that flowers ofM.oleiferapossess potent anti-inflammatory activity and are also a good source of natural antioxidants.Further study is needed to identify the chemical compounds responsible for their anti-inflammatory activity.
文摘Dietary intake of 0.1% fucoxanthin significantly reduced lipid hydroperoxide levels of liver and abdominal white adipose tissue (WAT) of obese/diabetes KK-Ay mice. The fucoxanthin supplementation also significantly reduced blood glucose level and hepatic lipid contents of the mice. Oxidative stress is known to be induced in hyperglycemia and high fat conditions. Therefore, in vivo antioxidant activity of fucoxanthin found in the present study could be attributed to its anti-diabetic effect and its decreasing effect on hepatic lipids. On the other hand, little effect of fucoxanthin on lipid hydroperoxide levels was found in normal ICR mice. Although the content of fucoxanthin metabolites in the abdominal WAT of KK-Ay mice was about 50 times higher that in the liver, there was little difference in its In Vivo antioxidant activity between in the liver and in the abdominal WAT. These results suggest that well-known ability of fucoxanthin to scavenge active oxygen species and/or free radicals would not be a main reason to explain its In Vivo antioxidant activity.
文摘Objective:To investigate the antioxidant and anti-inflammatory activity of orally administered methanolic leaf extract of Dalbergia paniculala(D.paniculata) in Carrageenan induced inflammation in rats.Methods:In vitro antioxidant activity was evaluated for superoxide radical, Hydroxyl radical and DPPH radical scavenging activity.Three doses 200 mg/kg,400 mg/kg and 800 mg/kg of D.paniculala were tested for anti-inflammatory activity in Carrageenan induced rat paw edema model and paw thickness was measured every one hour up to 6 h. Results:The melhanolic leaf extract of D.paniculala produced dose dependent inhibition of Superoxide radical,Hydroxyl radical and OPPH radicals.In Carrageenan induced inflammation model,all three doses produced significant percentage inhibition of rat paw edema and 800 mg/kg dose produced maximum percent inhibition of rat paw edema(47.83%) at 3h compared to control group.Conclusions:In the present study we found that methanolic leaf extract of D.paniculata showed good in vitro antioxidant activity and in vivo anti-inflammatory activity in rats.
基金supported by the National Technologies R&D Program of China (2006BAD01A02)the Excellent Medium-Youth Scientist Scientific Research Reward Fundation of Shandong Province, China (BS2009NY036)the Youth Science and Technology Creative Fundation Item of Shandong Agricultural University, China
文摘The anthocyanin pigment extracted from green-wheat-bran was studied to identify its antioxidant activity.The antioxidant activities of the pigment were evaluated by anti-lipid peroxidation,total antioxidant activity （TAA）,superoxide anion radical scavenging activity （SARSA）,active oxygen scavenging activity （AOSA）,and DPPH （1,1-diphenyl-2 picrylhydrazyl free radical） radical scavenging activity.The results showed that the pigment had higher antioxidant activity and TAA,SARSA,AOSA and DPPH.scavenging activities at a certain concentration than Vc （antiscorbutic vitamin,vitamin C）,and the capacity increased with the increase of pigment concentration.Its TAA was 51.06 U mL-1,1.73 times of Vc,and SARSA 18 025.21 U mL-1,2.26% higher than Vc,and AOSA 3 776.31 U mL-1,1.24 times of Vc.As to the DPPH.scavenging activity of the pigment,there was a trend that higher concentration performed higher activity significantly improved with the company of Vc.The pigment showed significant antioxidant activities evaluated by different assays.Results will provide a better understanding on antioxidant activity of green wheat and allow the screening or breeding of green wheat varieties with higher antioxidant activity for food processing.
基金supported by the Agricultural Scientific and Technological Independent Innovation Fund Project of Jiangsu Province[Grant No.CX(20)2030]the Modern Agricultural(Flower)Industrial Technology System Construction Project of Jiangsu Province[Grant No.JATS[2021]489].
文摘Flavonoids have attracted considerable attention due to their health benefits. This study aimed to investigate the flavonoid profiles and antioxidant activity of Paeonia lactiflora petal flavonoid extract(PPF). The UHPLC-ESI-Q-Exactive HF MS/MS method was established for characterization, and 21 predominant flavonoid compounds were tentatively identified in PPF. Among them, isoscutellarein-7-(6’-acetylallosyl-(1->2)-glucoside) and scutellarin methylester were discovered in PPF for the first time. Pretreatment with PPF significantly reduced H2O2-induced cell damage, ROS accumulation, and malondialdehyde content and increased the activity of SOD, CAT, and GSH-Px in buffalo rat liver 3A(BRL3A) cells. Moreover, the expression of nuclear Factor E2-related factor(Nrf2) was upregulated by PPF, whose expression trend was consistent with that of heme oxygenase-1(HO-1), glutamate-cysteine ligase catalytic subunit(GCLC), and NAD(P)H quinone oxidoreductase-1(NQO1). These findings suggested that herbaceous peony flavonoids can be used as a natural bioactive agent to prevent oxidative stress.
文摘In this study the antioxidant activity of barley malt rootlet (BMR) extracts w</span><span style="font-family:"">as</span><span style="font-family:""> evaluated in heat treated corn oil up to 5 hours at 185</span><span style="font-family:"">°</span><span style="font-family:"">C frying temperature. The antioxidant activity </span><span style="font-family:"">of </span><span style="font-family:"">BMR extracts was measured at 25, 50, 100 and 150 ppm concentrations. The free and bound antioxidant phenolics were extracted from BMR using three different extraction methods. Conventional solvent extraction (CSE), microwave assisted extraction (MAE) and autoclave assisted pretreated solvent extraction (APSE). In the present experiment, the total phenolic content and antioxidant activity of the various extracts w</span><span style="font-family:"">ere</span><span style="font-family:""> measured. Thiobarbituric acid reactive substances (TBARS) assay was used to evaluate the ability of the BMR to protect lipid peroxidation in corn oil at 185</span><span style="font-family:"">°</span><span style="font-family:"">C frying temperature. The formation of TBARS at 5 hours of heat treated corn oil ha</span><span style="font-family:"">s</span><span style="font-family:""> shown similar antioxidant levels in 150 ppm butylated hydroxytoluene (BHT) or MAE free phenolic extract added to corn oil. TBARS value for BHT was 1.896 ± 0.013 μg/mL of corn oil and for MAE was 1.896 ± 0.034 μg/mL of corn oil. The highest level of antioxidant activity was found for the free phenolic extracts. The order of inhibition of oxidation was found to be for free phenolics as follows: BHT (100 ppm) > APSE (50 ppm) > MAE (100 ppm) > CSE (100 ppm).
文摘Oxidative stress plays a key role in the pathogenesis of various diseases.Nature antioxidants derived from traditional Chinese medicine protect the cells and tissues from oxidative stress by scavenging free radicals and reactive oxygen species,therefore have a great potential in delaying ageing process and preventing oxidative stress-related disease.In this article,the antioxidant benefits of common single and compound traditional Chinese medicine in protecting tissues from injury are reviewed,along with identification of the various constituents that possess antioxidant activity and its mechanism were reviewed.
文摘Objective: In this study, we plan to measure plasma Catalase (CAT), Antioxidant Activity (AOA) and Glu- tathione-S-Transferase (GST) levels to understand whether oxidative stress develops or not and whether or not the detoxification mechanism properly functions in children with Attention Deficit and Hyperactivity Disorder (ADHD) with unknown etiology and pathogenesis. Method and Results: Plasma CAT, AOA, and GST activities were spectrophotometrically measured in forty patients (average age 10.27 ± 2.54) and thirty-five (average age, 9.97 ± 2.59) healthy individuals as the control group. While the CAT activity showed no difference in the patient group (P > 0.05) compared to the control group, AOA and GST levels were found significantly meaningful (P = 0.001). Conclusion: In this pilot study ,the study shows that no oxidative stress develops in individuals with ADHD in high AOA and stable CAT activity, and that the de- toxification mechanism functions extremely in high GST activity. These findings need to be supported by other studies.
基金supported by Department of Biotechnology,Government of India for Interdisciplinary Programme of Life Sciences for the Advanced Research and Education(IPLS–Reference No:BT/PR4572/INF/22/147/2012)
文摘Objective: To investigate L-3, 4-dihydroxyphenylalanine(L-dopa, anti-Parkinson drug),anti-inflammatory activity, proximate nutritional composition and antioxidant potential of Mucuna macrocarpa(M. macrocarpa) beans.Methods: L-dopa content was determined and quantified by high performance thin layer chromatography and reversed phase high-performance liquid chromatography(RPHPLC) methods. Anti-inflammatory activity was performed by in vitro protein denaturation inhibition and human red blood cell membrane stabilisation activity. Proximate composition and elemental analysis were also investigated. The antioxidant potential(2,2-diphenyl-1-picrylhydrazyl, N-N-dimethyl-phenylenediamine and ferric-reducing antioxidant power) of M. macrocarpa beans were evaluated by using different extraction solvents. The RP-HPLC analysis also quantified significant phenolics such as gallic acid, tannic acid, p-hydroxybenzoic acid and p-coumaric acid.Results: RP-HPLC quantification revealed that M. macrocarpa beans contain a high level of L-dopa [(115.41 ± 0.985) mg/g] which was the highest among the Mucuna species from Indian sub-continent. Water extract of seed powder showed strong antiinflammatory and antioxidant potential. Proximate composition of M. macrocarpa beans revealed numerous nutritional and anti-nutritional components. RP-HPLC analysis of major phenolics such as tannic acid(43.795 mg/g), gallic acid(0.864 mg/g), p-coumaric acid(0.364 mg/g) and p-hydroxybenzoic acid(0.036 mg/g) quantified successfully from M. macrocarpa beans respectively.Conclusions: This study suggests that M. macrocarpa is a potential source of L-dopa with promising anti-inflammatory, antioxidant and nutritional benefits.
文摘Super oxide anion had been known as a critical role in a phagocytic cell when microorganisms invade inside. However, this radical seldom need for a clean environment such in a developed country. Moreover, this agent sometimes triggered as serious factor in the site of inflammation. There are many papers which concerned newly found anti-oxidative substances. However, many reports only focused on the molecular basis in vitro, how oxidative stress damaged the human tissue. The key factor for oxidative stress needs to be discussed first for immunological standpoint, such as armed reduction treaty. In other words, minimum armed force is necessary for an invasion by outer or inner irregular cells. On the basis of phagocytic function of the cell in vivo, we tried to access anti-oxidative activity by employing peritoneal murine macrophage and human monocyte. So, the purpose of this study is to establish a conventional but tailor made system for which is useful for evaluating the anti-oxidative activity to different constition. Especially in human peripheral monocyte, the sample was tested each constitution such in granulocyte rich type and lymphocyte rich typ. In order to establish the direct estimation by phagocytic cell, a murine peritoneal exudates cell suspension was obtained after one week of oral administration with anti-oxidative sample. The samples we selected were traditional Chinese medicine, Shi-Quan-Da-Bu-Tang (SDT), Bu-Zong-Ye-Qi-Tang (BYT) and Shao-Chin-Rong-Tang sCRT), Agaricus, Chlorella, and Propolis. The amount of generated super oxide anion was calculated through measuring the optical density change of this supernatant using cytochrome-C which was reduced by generated super oxide anion in the phagocytic cell. The generated super oxide anion after administration of Agaricus, Chlorella, SDT, BYT, sCRT and Propolis were 2.64, 1.95, 1.24, 1.25, 2.88, 2.55 × 10﹣5 mmol/ml, respectively, whereas 2.85 × 10﹣5 mmol/ml in control group. The fermented sample from SDT, BYT, sCRT and microfied Propolis were also tested and the value of super oxide anion were 0.62, 0.84, 1.50 and 2.55 × 10﹣5 mmol/ml, respectively. In this report, we discussed the direct method for measuring the generated super oxide anion of macrophages, especially from different constitution.
基金financially supported by the National Natural Science Foundation of China(No.31430067,31601475,31571876,and 31671807)the 13th Five-Year Plan(No.2016YFD0401402)
文摘Soybeans are known as a promising source of bioactive peptides.However,knowledge on the antioxidant behaviors of soybean protein hydrolysate(SPH)in the human intestinal epithelium is limited.In this study,SPH was prepared with Alcalase and subsequently ultrafiltered into four peptide fractions as SPH-I(<3 kDa),SPH-II(3~5 k Da),SPH-III(5~10 k Da)and SPH-IV(>10 kDa).The antioxidant properties of SPH and membrane fractions were investigated using different chemical assays and their protective effects against oxidative stress were evaluated using H2 O2-stressed human intestinal Caco-2 cells.Results showed that SPH-I exhibited the strongest 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging activity(IC50=2.56 mg/m L)and reducing capacity while SPH-III had the best metal ion-chelating activity(IC50=0.29 mg/m L).Both SPH and the peptide fractions dose-dependently suppressed intracellular reactive oxygen species(ROS)accumulation induced by H2O2 in Caco-2 cells,but the strongest inhibitory effect was observed for SPH-I.Amino acid(AA)results revealed that SPH-I was rich in hydrophobic and antioxidant AAs,which could contribute to its stronger antioxidant properties.Additionally,SPH-I protected Caco-2 cells from H2O2-induced oxidative stress via inhibiting lipid peroxidation and stimulating antioxidant enzyme activities.These results suggest that SPH-I and constitutive peptides can be beneficial ingredients with antioxidant properties and protective effects against ROS-mediated intestinal injury.
文摘Carbonic anhydrase isozyme CA3 protects cells against oxidative stress. Ectopic expression of murine Ca3, but not Ca2, protects proto-oncogene Evi1 expressing Rat1 fibroblast cells (ca3low) against hydrogen peroxide (H2O2) induced stress. Ca3 is S-glutathionylated via glutathione adducts with cysteines 181 and 186. Substitution of both Ca3 cysteines with serine fails to protect cells from oxidative stress. Insertion of cysteine at 181 and 186 in Ca2 is insufficient for conferring efficient anti-oxidant activity. This shows for the first time that S-glutathionylation of cys181 and cys186 residues is required for Ca3 anti-oxidant activity but that additional factors are also required.
文摘The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 oC have been studied. The following flavonoids;quercetin, rutin and morin significantly protected eryt-hrocytes against lipid peroxidation caused by H2O2. This inhibition of lipid peroxidation could be explained by the presence of at least two hydroxyl groups in ring B of the flavonoid structure, regardless of their positions. However, the flavonoids;quercetin, 3,5,7-trihy- droxy-4'-methoxy flavone-7-rutinoside and 3- hydroxy flavone significantly protected eryt-hrocytes against protein degradation. This inhibition could also be explained by the presence of a hydroxyl group at C-3 in ring C of the flavonoid structure. Quercetin and 3,5,7-trihydroxy-4'- methoxy flvone-7-rutinoside significantly protected erythrocytes against loss of deformability and increased osmotic fragility, indicating that the loss of erythrocyte deformability and the increase in osmotic fragility of erythrocytes exposed to H2O2 are related to protein degradation rather than to lipid peroxidation. The other flavonoids (chrysin, 2-carboxy ethyl dihydroxy flavone, apigenin, cirsimaritin, α-naphto flavone and flavanone) failed to protect erythrocytes against the observed oxidative damages. The results demonstrate the importance of the chemical groups substituted on the basic skeleton of the flavonoids in dictating the type of antioxidant activity, and also demonstrate the hemorheological potentials of flavonoids that have particular protein-antioxidant activities.
文摘From the ethyl acetate extract of the medicinal plant Graptophyllum glandulosum Turrill, five known compounds: Lupeol (1), Oleanolic acid (2), Chrysoeriol (3), N-methyl-isonicotinamide (4) and β-sitosterol 3-O-β-D-glucopyranoside (5) were isolated. In addition, oxidation reactions carried out on lupeol (1) yielded two semi-synthetic compounds, including a previously unreported: (20R)-formyloxy-29-nor-lupan-3-one (1b) and one other well-known Lupenone (1a). The structures of natural and semi-synthetic compounds were determined by analysis of 1D-(1H, 13C), 2D-(COSY, HSQC and HMBC) NMR data in conjunction with mass spectrometry (TOFESIMS and HR-TOFESIMS) and by comparison with the reported data. The evaluation of antimicrobial activities of substrate (1) as well as semi-synthetic derivatives (1a and 1b) using broth microdilution method showed that compound 1b was the most active (16 ≤ MIC ≤ 32 μg/mL) against Escherichia coli, Staphylococcus aureus and Candida albicans compared to the starting material 1 (16 ≤ MIC ≤ 64 μg/mL) and derivative 1a (32 ≤ MIC ≤ 64 μg/mL).
基金supported by Key Science and Technology Innovation Team of Shaanxi Province(No.2022TD-33)National Natural Science Foundation of China(Grant Nos.21373161,21504067)。
文摘Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculated using DMol3,since HMX and O are key substances in decomposition process.And the relationship between the adsorption energy of HMX,O on metal oxides(TiO_(2),Al_(2)O_(3),PbO,CuO,Fe_(2)O_(3),Co_(3)O_(4),Bi_(2)O_(3),NiO)and experimental T30 values(time required for the decomposition depth of HMX to reach 30%)was depicted as volcano plot.Thus,the T30 values of other metal oxides was predicted based on their adsorption energy on volcano plot and validated by previous experimental data.Further,the adsorption energy of HMX on ZrO_(2)and MnO_(2)was predicted based on the linear relationship between surface energy and adsorption energy,and T30 values were estimated based on volcano plot.The apparent activation energy data of HMX/MgO,HMX/SnO_(2),HMX/ZrO_(2),and HMX/MnO_(2)obtained from DSC experiments are basically consistent with our predicted T30 values,indicating that it is feasible to predict the catalytic activity based on the adsorption calculation,and it is expected that these simple structural properties can predict adsorption energy to reduce the large quantities of computation and experiment cost.
