The molecular structure and radical scavenging activity of three novel antioxidants from Lespedeza Virgata, lespedezavirgatol, lespedezavirgatal, and lespedezacoumestan, have been studied using density functional theo...The molecular structure and radical scavenging activity of three novel antioxidants from Lespedeza Virgata, lespedezavirgatol, lespedezavirgatal, and lespedezacoumestan, have been studied using density functional theory with the B3LYP and BhandHLYP methods. The optimized geometries of neutral, radical cation, radical and anion forms were obtained at the B3LYP/6-31G(d) level, in which it was found that all the most stable conformations contain intramolecular hydrogen bonds. The same results were obtained from the MP2 method. The homolytic O-H bond dissociation enthalpy and the adiabatic ionization potential of neutral and anion forms for the three new antioxidants and adiabatic electron affinity and H-atom affinity for hydroxyl radical, superoxide anion radical, and hydrogen peroxide radical were determined both in gas phase and in aqueous solution using IEF-PCM and CPCM model with UAHF or Bondi cavity. The antioxidant activities and reactive oxygen species scavenging mechanisms were then discussed, and the results obtained from different methods are consistent. Furthermore, the antioxidant activities are consistent with the experimental findings of the compounds under investigation.展开更多
AIM: To determine the effect of melatonin pre- and post-treatment on the severity of L-arginine (L-Arg) -induced experimental pancreatitis in rats. METHODS: Male Wistar rats (25) were divided into five groups. T...AIM: To determine the effect of melatonin pre- and post-treatment on the severity of L-arginine (L-Arg) -induced experimental pancreatitis in rats. METHODS: Male Wistar rats (25) were divided into five groups. Those in group A received two injections of 3.2 g/kg body weight L-Arg i.p. at an interval of 1 h. In group MA, the rats were treated with 50 mg/kg body weight melatonin i.p. 30 min prior to L-Arg administration. In group AM, the rats received the same dose of melatonin 1 h after L-Arg was given. In group M, a single dose of melatonin was administered as described previously. In group C the control animals received physiological saline injections i.p. All rats were exsanguinated 24 h after the second L-Arg injection. RESULTS: L-Arg administration caused severe necrotizing pancreatitis confirmed by the significant elevations in the serum amylase level, the pancreatic weight/body weight ratio (pw/bw), the pancreatic IL-6 content and the myeloperoxidase activity, relative to the control values. Elevation of the serum amylase level was significantly reduced in rats given melatonin following L-Arg compared to rats injected with L-Arg only. The activities of the pancreatic antioxidant enzymes (Cu/Zn-superoxide dismutase (CulZn-SOD) and catalase (CAT)) were significantly increased 24 h after pancreatitis induction. Melatonin given in advance of L-Arg significantly reduced the pancreatic CAT activity relative to that in the rats treated with L-Arg alone. In the liver, L-Arg significantly increased the lipid peroxidation level, and the glutathione peroxidase and Cu/Zn-SOD activities, whereas the Mn-SOD activity was reduced as compared to the control rats. Melatonin pre-treatment prevented these changes. CONCLUSION: Melatonin is an antioxidant that is able to counteract some of the L-Arg-induced changes during acute pancreatitis, and may therefore be helpful in the supportive therapy of patients with acute necrotizing pancreatitis.展开更多
The effects of photogenerated-hole scavengers(ascorbic acid,oxalic acid,humic acid and citric acid)on chalcopyrite bioleaching in the presence of visible light were studied using Acidithiobacillus ferrooxidans(A.ferro...The effects of photogenerated-hole scavengers(ascorbic acid,oxalic acid,humic acid and citric acid)on chalcopyrite bioleaching in the presence of visible light were studied using Acidithiobacillus ferrooxidans(A.ferrooxidans).Four sets of bioleaching experiments were performed:(1)visible light+0 g/L scavenger,(2)visible light+0.1 g/L of different scavenger(ascorbic acid,oxalic acid,humic acid and citric acid),(3)dark+0.1 g/L of different scavenger(ascorbic acid,oxalic acid,humic acid and citric acid),and(4)dark+0 g/L scavenger(control group).The results showed that ascorbic acid and oxalic acid could act as photogenerated-hole scavengers and significantly enhance chalcopyrite bioleaching under visible light.The dissolved copper in the light group without scavenger was only 18.7%higher than that of the control group.The copper extraction rates of the light groups with oxalic acid and ascorbic acid were respectively 30.1%and 32.5%higher than those of the control group.Scanning electron microscopy(SEM),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR)analyses indicated that ascorbic acid and oxalic acid as photogenerated-hole scavenger could capture photo-generated holes and inhibit jarosite formation on the chalcopyrite surface,thereby enhancing bioleaching of chalcopyrite under visible light.展开更多
A novel heterogeneous catalytic ozonation process in water treatment was studied, with a copper-loaded activated carbon (Cu/AC) that was prepared by an incipient wetness impregnation method at low temperature and te...A novel heterogeneous catalytic ozonation process in water treatment was studied, with a copper-loaded activated carbon (Cu/AC) that was prepared by an incipient wetness impregnation method at low temperature and tested as a catalyst in the ozonation of phenol and oxalic acid. Cu/AC was characterized using XRD, BET and SEM techniques. Compared with ozonation alone, the presence of Cu/AC in the ozonation processes significantly improves the degradation of phenol or oxalic acid. With the introduction of the hydroxyl radical scavenger, i.e., turt-butanol alcohol (t-BuOH), the degradation efficiency of both phenol and oxalic acid in the Cu/AC catalyzed ozonation process decreases by 22% at 30 min. This indicates that Cu/AC accelerates ozone decomposition into certain concentration of hydroxyl radicals. The amount of Cu(II ) produced during the reaction of Cu/AC-catalyzed ozonation of phenol or oxalic acid is very small, which shows that the two processes are both heterogeneous catalytic ozonation reactions.展开更多
The human plasma protein binding of water soluble flavonoids in the peels of five spices of citrus fruits was studied by ultrafiltration combined with HPLC.The flavonoids were extracted separately by hot and cold wate...The human plasma protein binding of water soluble flavonoids in the peels of five spices of citrus fruits was studied by ultrafiltration combined with HPLC.The flavonoids were extracted separately by hot and cold water,and higher total flavonoid contents were detected in the former extracts than the latter ones.All the extracts show significant scavenging abilities to both ABTS and DPPH free radicals,which indicates the health benefits of the water extracts of citrus fruits peels.For DPPH radical,the IC50values of hot extract follow as Navel orange(NO)≈Mandarin orange(MO)< Lemon(LE)< Lo tangerine(LO)< Pomelo(PO),while the rank is NO< PO<LE≈MO<LO for ABTS radical.The HPLC results reveal that the kinds and contents of the flavonoids detected in the extracts are different among the species.MO extract has the most neohesperidin dihydrochalcone of 118.76 μmol/L and quercetrin of 211.81 μmol/L of which are much more than the rest extracts.Pomelo extract has the most plentiful flavonoids of naringin with a concentration of 303.28 μmol/L.The high contents of myricetrin and dihydromyricetin which both are potent free radical scavengers may explain the highest free radical scavenging activity of the NO extract.The plasma binding rates decrease with the increasing concentrations of flavonoids,and the flavonoids having plenty hydroxyl groups on both A ring and B ring of the molecular skeleton have relative higher plasma binding rates.In addition,the plasma binding rates of flavonoids with saturated C3-C4 bond decrease significantly with the increasing concentrations.展开更多
Background In type 2 diabetes mellitus (T2DM), high-density lipoprotein (HDL) impairs its anti-atherogenic properties and even develops to a pro-inflammatory and pro-atherogenic phenotype because of abnormal compo...Background In type 2 diabetes mellitus (T2DM), high-density lipoprotein (HDL) impairs its anti-atherogenic properties and even develops to a pro-inflammatory and pro-atherogenic phenotype because of abnormal compositions and modifications. In this study, we ex- amined the effects and the related mechanisms of glycation of HDL on the proliferation and migration of vascular smooth muscle cells (VSMCs). Methods & Results Glycated HDL (G-HDL) was modified with D-glucose (25 mmol/L) in vitro. Diabetic HDL (D-HDL) was isolated from T2DM patients. Rat VSMCs were isolated from the thoracic aortas. Human VSMCs were obtained from ScienCell Research Laboratories. Alpha-actin was detected through immunofiuorescence. VSMC proliferation was assayed by Cell Count. VSMC migration was determined by transwell chamber and scratch-wound assay. Intracellular reactive oxygen species (ROS) was detected based on ROS-medi- ated 2',7'-dichlorofluorescein (DCFH-DA) fluorescence. Compared to native HDL (N-HDL), G-HDL remarkably promoted VSMC prolif- eration and migration in the dose and time-dependent manners. In addition, G-HDL enhanced ROS generation in VSMCs. However, the ROS scavenger, N-acetylcysteine, efficiently decreased ROS production and subsequently inhibited the proliferation of VSMCs induced by G-HDL. Similarly, D-HDL from T2DM patients also promoted ROS release and VSMC proliferation and migration. Conclusions HDL either glycated in vitro or isolated from T2DM patients triggered VSMC proliferation, migration, and oxidative stress. These results might partly interpret the higher morbidity of cardiovascular disease in T2DM patients.展开更多
Reactive oxygen species (ROS) scavengers, including ascorbate peroxidase, superoxide dismutase, catalase and peroxidase, are the most commonly used biomarkers in assessing an organisms' response to many biotic and ...Reactive oxygen species (ROS) scavengers, including ascorbate peroxidase, superoxide dismutase, catalase and peroxidase, are the most commonly used biomarkers in assessing an organisms' response to many biotic and abiotic stresses. In this study, we cloned an 866 bp GST(phi) gene in Lemna minor and investigated its characteristics, expression and enzymatic activities under 75 lamol/L cadmium concentrations in comparison with other ROS scavengers. GST(phi) gene expression patterns were similar to those of other scavengers of ROS. This suggests that GST(phi) might be involved in responding to heavy metal (cadmium) stress and that its expression level could be used as a bio-indicator in monitoring cadmium pollution.展开更多
A method for oxidative degradation of 1,4-dioxane (1,4-D) in waste water using a combination of ozone oxidation with UV irradiation (ozone/UV) treatment was investigated. The results showed that 1,4-D was degraded...A method for oxidative degradation of 1,4-dioxane (1,4-D) in waste water using a combination of ozone oxidation with UV irradiation (ozone/UV) treatment was investigated. The results showed that 1,4-D was degraded by ozone/UV treatment up to 90 min. The optimum concentration for the injected ozone gas was about 40 g·m^3 under a constant level of UV irradiation. Furthermore, solid phase extraction and GC-MS analysis showed no specific or reproducible peaks due to by-products of 1,4-D. It was therefore concluded that 1,4-D was completely degraded by ozone/UV treatment. In contrast, the amount of 1,4-D remaining decreased slowly in the presence of HCOf or CI. It was suggested that the degradation of 1,4-D, which results from .OH oxidation, was retarded by the presence of HCO3 or CI, which act as radical scavengers.展开更多
The lethal effect produced by sunlight in bacteria depends on the photodynamic action of the ultraviolet component of the radiation. Neither the reactive oxygen species involved nor the targets for damage have been ce...The lethal effect produced by sunlight in bacteria depends on the photodynamic action of the ultraviolet component of the radiation. Neither the reactive oxygen species involved nor the targets for damage have been certainly identified, and the aim of this study was to address these issues. During exposures to natural sunlight, photo-protection provided by nitrogen sparging was compared with which provided by the addition of L-histidine (an efficient scavenger for hydroxyl radical and singlet oxygen) or mannitol (an hydroxyl radical scavenger which reacts poorly with singlet oxygen) to the irradiation medium. Both scavengers reproduced for the most part the effect of oxygen depletion, indicating that damage depends mainly on hydroxyl radical generation. Survival of irradiated bacteria decreased considerably when they were cultured using a substrate unsuitable for fermentation, suggesting that respiration impairment is a key factor in cell killing. This observation is in keeping with the notion that the respiratory chain is the main target for the action of sunlight in Escherichia coli.展开更多
The present study investigated potential effectiveness of certain chemical candidates for controlling internal phosphorus loading, and for delineating inactivation pattern in sediment depths of an eutrophic pond under...The present study investigated potential effectiveness of certain chemical candidates for controlling internal phosphorus loading, and for delineating inactivation pattern in sediment depths of an eutrophic pond under simulated mesocosm condition. Chemical administration (@ 30 mg/dm3) resulted in phosphate precipitation from water column concomitant with inactivation in sediments, under specific pH range and/or redox regime. The alum-lime combination dosing wrought the maximum reduction in orthophosphate (65.6%) and soluble reactive phosphate (71.9%) in water plus the utmost increment in sediment-P (0.257 ppm). The inactivated P forms typically exhibited a downhill concentration gradient with highest sequestration in the uppermost sediment stratum. Ironbound P displayed the highest mobility while calcium- and aluminum- bound P behaved almost immune to internal feedback dynamics. The combo-treatment was established as the most effective phosphate scavenging and confiscating agent, to be adopted as chemical remediation regime for de-eutrophication, restoration and rehabilitation of the water body.展开更多
Seaweed Complex Preparation (SCP) is a clinical traditional Chinese medicine preparation which is composed of seven traditional Chinese herbs, and it has been used for treatment of lung cancer, liver cancer and dige...Seaweed Complex Preparation (SCP) is a clinical traditional Chinese medicine preparation which is composed of seven traditional Chinese herbs, and it has been used for treatment of lung cancer, liver cancer and digestive cancer. However, little infor- mation is available about the pharmacodynamic basis. The antitumor, immunomodulatory and free radical scavenging effects of SCP were evaluated in this study. Transplanted tumor in vivo method was used to determine the antitumor effect. The effects on spleno- cyte proliferation and phagocytosis of macrophages in tumor-bearing mice were measured by the MTT method and the phagocytizing cock red blood cell (CRBC) method respectively. The scavenging activities of SCP on DPPH and hydroxyl radicals in vitro were investigated. It was found that the medium-dose and high-dose of SCP could significantly inhibit the growth of transplanted hepatic tumor of murine hepatocarcinoma cell line H22, and promote proliferation of splenocytes and phagocytosis of macrophages. SCP possessed noticeable scavenging activities on DPPH and hydroxyl radicals. The antiturnor effects of SCP might be achieved by im- proving immune system and scavenging free radicals, which is in accordance with the viewpoint of traditional Chinese medicine in promoting the body resistance and eliminating pathogenic factors for cancer treatment.展开更多
With the increasing interest on natural products discovery, utilization of plant parts which are commonly disregarded is another breakthrough. This study sought to determine the secondary metabolites present, phenolic...With the increasing interest on natural products discovery, utilization of plant parts which are commonly disregarded is another breakthrough. This study sought to determine the secondary metabolites present, phenolic contents, radical scavenging activities and antibacterial properties of 10 selected ornamental flowers which were Adenium obesum, Allamanda cathartica, Bougainvillea glabra, Catharanthus roseus, Caesalpinia pulcherrima, Heliconia subulata, Ixora coccinea, Mussaenda philippica, Tecoma stans and Torenia fournieri, from Nueva Vizcaya, Philippines. The ethanolic crude extracts were subjected to thin layer chromatography (TLC) phytochemical screening. Total phenolics expressed as mg AAE/g sample were determined through Folin-Ciocalteu method. Radical scavenging activities were measured using DPPH assay. Antibacterial activities were assessed through TLC bioautography. To quantify bacterial susceptibility of C. pulcherrima, MIC and MBC were employed in the ethyl acetate sub-fraction. TLC showed different types of phenolics, alkaloids, essential oils and terpenes. T. fournieri showed the highest total phenolics with 155 mg AAE/g while H. subulatahad showed the lowest with 3.50 mg AAE/g. Measurement of IC59 showed that H. subulata had the highest antioxidant activity followed by T. fournieri with 303 ppm and 320 ppm, respectively. H. subulata having the least amount of total phenolics had greatest radical scavenging activity. This indicates that other than phenolics, other metabolites can pose great antioxidant activities. The antibacterial testing showed that M. philippica, 1. coccinea, 1-1. subulata, C. pulcherrima and A. cathartica were bioactive against Staphylococcus aureus and Escherichia coll. MIC and MBC of C. pulcherrima ethyl acetate sub-fraction is within the range of 2.5-10 mg/mL.展开更多
Functional properties of Talbina were used in ancient Arab for nutritional purpose. It was a meal made from barley flour and milk. The high antioxidant Talbina was formulated from whole flour of harley and oat, milk, ...Functional properties of Talbina were used in ancient Arab for nutritional purpose. It was a meal made from barley flour and milk. The high antioxidant Talbina was formulated from whole flour of harley and oat, milk, date palm syrup (debis) and date palm seeds. The chemical composition, organoleptic properties and antioxidant activity of high antioxidant Talbina were determined. Sensory evaluation of traditional and high antioxidant Talbina showed that the developed product Talbina was considered as good for overall acceptability of all panelists. Also, the formulated Talbina contains high values of antioxidants components and natural nutrients. The antioxidant activity of formulated Talbina containing barley or oat may be due to presence of phenolic compounds and proanthocyanidins in the barley and oat. Increasing the antioxidant activity of high antioxidant Talbina containing barley and oat may be due to the adding of dates palm seeds which contain very high values of phenolic compounds and other antioxidants components. Date palm seeds as well as barley and/or oat give high antioxidants components which protect cells from oxidative stress and help to reduce the risk of cancer and heart disease as well as natural anti-depressant. Moreover, increasing the antioxidant activity in the formulated Talbina may play a role for reducing power, radical scavenging activity and the lipid peroxidation inhibition. In conclusion, supplementation of traditional Talbina containing barley and/or oat with date palm syrup (debis) and date palm seeds can produce simple and healthy meal to provide a good source of daily dietary antioxidants and micronutrients.展开更多
OBJECTIVE: To study the effects of Danhong injec- tion (DHI) on expression of the macrophage scaven- ger receptor 1 (MSR1) and ATP-binding cassette, sub-family A member 1 (ABCA1) genes, which en- code scavenger...OBJECTIVE: To study the effects of Danhong injec- tion (DHI) on expression of the macrophage scaven- ger receptor 1 (MSR1) and ATP-binding cassette, sub-family A member 1 (ABCA1) genes, which en- code scavenger receptor-A I (SR-AI) and ATP-bind- ing cassette transporter 1 (ABCA1), respectively, as a potential anti-atherosclerotic mechanism. METHODS: Human U937 cells were stimulated by in- cubation with 100 nM phorbo112-myristate 13-ace- tate (PMA) for 48 h.These stimulated, monocyte-like cells were then incubated for 24 h with 50 mg/L oxi- dized low-density lipoprotein (ox-LDL, to induce foam cell formation), together with a liver X recep- tor (LXR) agonist or with different DHI concentra- tions. MSR1 and ABCA1 mRNA levels were mea- sured by fluorescence-based quantitative PCR. RESULTS: Compared with control cells (which re- ceived only ox-LDL), cells treated with both ox-LDL and 10 IJmol/L LXR agonist showed lower MSR1 ex-pression (but this effect was not statistically signifi- cant, P〉0.05) and higher ABCA1 expression (P〈 0.01). Cells that received ox-LDL and 3 mL/L DHI possessed higher MSR1 mRNA levels than the con- trols, whereas cells treated with ox-LDL and higher DHI concentrations (10, 30 or 60 mL/L) showed low- er MSR1 expression levels (but the differences ob- served between DHI concentration groups were not statistically significant, P〉0.05). ABCA1 expression in cells treated with ox-LDL and 3, 10 or 30 mL/L DHI was higher than in the control cells, and increased with increasing DHI concentration (P〈0.05). ABCA1 expression in cells treated with ox-LDL and the highest DHI concentration tested (60 mL/L) was not significantly different from that in the controls. ABCA1 mRNA levels in cells treated with ox-LDL and DHI were similar to, or lower than, those in cells treated with ox-LDL and the LXR agonist. CONCLUSION: DHI does not affect MSR1 mRNA lev- els in ox-LDL-treated U937 cells. However, at certain concentrations (10 and 30 mL/L), DHI significantly increases ABCA1 mRNA levels. Therefore, the an- ti-atherosclerotic action of DHI might be mediated by an increased expression of ABCA1.展开更多
Fenton reaction based on Fe2+-H2O2 system has been widely applied in water remediation, but the obvious drawbacks largely hinder its practical uses. Alternatively, heterogeneous nanomaterials with proper surface modif...Fenton reaction based on Fe2+-H2O2 system has been widely applied in water remediation, but the obvious drawbacks largely hinder its practical uses. Alternatively, heterogeneous nanomaterials with proper surface modification could be used as Fenton-like catalysts. Surface doping of Ti O2 could concentrate the pollutants surrounding the Fe3O4 catalyst, which might benefit the catalytic performance of Fe3O4. Herein, we reported that Ti O2-doped Fe3O4 nanoparticles(NPs) could be used as high-performance Fenton-like catalyst for dye decoloration in near neutral environment, where the doping of Ti O2 on Fe3O4 surface dramatically improved the catalytic activity of Fe3O4 in Fenton-like reaction. Ti O2-doped Fe3O4 NPs catalyzed the decomposition of H2O2 to oxidize methylene blue without external energy supply, resulting in effective decoloration. Ti O2-doped Fe3O4 NPs showed high catalytic activity under various p H values and even in the presence of radical scavenger. More catalysts and H2O2 would facilitate the decoloration. At higher temperature, the decoloration became faster and more effective. The implication to the environmental applications of Ti O2-doped Fe3O4 NPs is discussed.展开更多
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (No.20902056 and No.20973108), the Innovation Foundation of Shanghai University, and the Leading Academic Discipline Project of Shanghai Municipal Education Commission (No.J50101).
文摘The molecular structure and radical scavenging activity of three novel antioxidants from Lespedeza Virgata, lespedezavirgatol, lespedezavirgatal, and lespedezacoumestan, have been studied using density functional theory with the B3LYP and BhandHLYP methods. The optimized geometries of neutral, radical cation, radical and anion forms were obtained at the B3LYP/6-31G(d) level, in which it was found that all the most stable conformations contain intramolecular hydrogen bonds. The same results were obtained from the MP2 method. The homolytic O-H bond dissociation enthalpy and the adiabatic ionization potential of neutral and anion forms for the three new antioxidants and adiabatic electron affinity and H-atom affinity for hydroxyl radical, superoxide anion radical, and hydrogen peroxide radical were determined both in gas phase and in aqueous solution using IEF-PCM and CPCM model with UAHF or Bondi cavity. The antioxidant activities and reactive oxygen species scavenging mechanisms were then discussed, and the results obtained from different methods are consistent. Furthermore, the antioxidant activities are consistent with the experimental findings of the compounds under investigation.
基金Supported by the Hungarian Scientific Research Fund (T042589).
文摘AIM: To determine the effect of melatonin pre- and post-treatment on the severity of L-arginine (L-Arg) -induced experimental pancreatitis in rats. METHODS: Male Wistar rats (25) were divided into five groups. Those in group A received two injections of 3.2 g/kg body weight L-Arg i.p. at an interval of 1 h. In group MA, the rats were treated with 50 mg/kg body weight melatonin i.p. 30 min prior to L-Arg administration. In group AM, the rats received the same dose of melatonin 1 h after L-Arg was given. In group M, a single dose of melatonin was administered as described previously. In group C the control animals received physiological saline injections i.p. All rats were exsanguinated 24 h after the second L-Arg injection. RESULTS: L-Arg administration caused severe necrotizing pancreatitis confirmed by the significant elevations in the serum amylase level, the pancreatic weight/body weight ratio (pw/bw), the pancreatic IL-6 content and the myeloperoxidase activity, relative to the control values. Elevation of the serum amylase level was significantly reduced in rats given melatonin following L-Arg compared to rats injected with L-Arg only. The activities of the pancreatic antioxidant enzymes (Cu/Zn-superoxide dismutase (CulZn-SOD) and catalase (CAT)) were significantly increased 24 h after pancreatitis induction. Melatonin given in advance of L-Arg significantly reduced the pancreatic CAT activity relative to that in the rats treated with L-Arg alone. In the liver, L-Arg significantly increased the lipid peroxidation level, and the glutathione peroxidase and Cu/Zn-SOD activities, whereas the Mn-SOD activity was reduced as compared to the control rats. Melatonin pre-treatment prevented these changes. CONCLUSION: Melatonin is an antioxidant that is able to counteract some of the L-Arg-induced changes during acute pancreatitis, and may therefore be helpful in the supportive therapy of patients with acute necrotizing pancreatitis.
基金Project(41773089)supported by the National Natural Science Foundation of ChinaProject(2017SK2255)supported by the Key R&D Program of Hunan Province,China+2 种基金Project(2015CNERC-CTHMP-05)supported by the Opening Foundation of the Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution,ChinaProject(CX20190136)supported by the Hunan Provincial Innovation Foundation for Postgraduates,ChinaProject(CSUZC201808)supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,China.
文摘The effects of photogenerated-hole scavengers(ascorbic acid,oxalic acid,humic acid and citric acid)on chalcopyrite bioleaching in the presence of visible light were studied using Acidithiobacillus ferrooxidans(A.ferrooxidans).Four sets of bioleaching experiments were performed:(1)visible light+0 g/L scavenger,(2)visible light+0.1 g/L of different scavenger(ascorbic acid,oxalic acid,humic acid and citric acid),(3)dark+0.1 g/L of different scavenger(ascorbic acid,oxalic acid,humic acid and citric acid),and(4)dark+0 g/L scavenger(control group).The results showed that ascorbic acid and oxalic acid could act as photogenerated-hole scavengers and significantly enhance chalcopyrite bioleaching under visible light.The dissolved copper in the light group without scavenger was only 18.7%higher than that of the control group.The copper extraction rates of the light groups with oxalic acid and ascorbic acid were respectively 30.1%and 32.5%higher than those of the control group.Scanning electron microscopy(SEM),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR)analyses indicated that ascorbic acid and oxalic acid as photogenerated-hole scavenger could capture photo-generated holes and inhibit jarosite formation on the chalcopyrite surface,thereby enhancing bioleaching of chalcopyrite under visible light.
基金Project(40973074) supported by the National Natural Science Foundation of China
文摘A novel heterogeneous catalytic ozonation process in water treatment was studied, with a copper-loaded activated carbon (Cu/AC) that was prepared by an incipient wetness impregnation method at low temperature and tested as a catalyst in the ozonation of phenol and oxalic acid. Cu/AC was characterized using XRD, BET and SEM techniques. Compared with ozonation alone, the presence of Cu/AC in the ozonation processes significantly improves the degradation of phenol or oxalic acid. With the introduction of the hydroxyl radical scavenger, i.e., turt-butanol alcohol (t-BuOH), the degradation efficiency of both phenol and oxalic acid in the Cu/AC catalyzed ozonation process decreases by 22% at 30 min. This indicates that Cu/AC accelerates ozone decomposition into certain concentration of hydroxyl radicals. The amount of Cu(II ) produced during the reaction of Cu/AC-catalyzed ozonation of phenol or oxalic acid is very small, which shows that the two processes are both heterogeneous catalytic ozonation reactions.
基金Project(21176263) supported by the National Natural Science Foundation of China
文摘The human plasma protein binding of water soluble flavonoids in the peels of five spices of citrus fruits was studied by ultrafiltration combined with HPLC.The flavonoids were extracted separately by hot and cold water,and higher total flavonoid contents were detected in the former extracts than the latter ones.All the extracts show significant scavenging abilities to both ABTS and DPPH free radicals,which indicates the health benefits of the water extracts of citrus fruits peels.For DPPH radical,the IC50values of hot extract follow as Navel orange(NO)≈Mandarin orange(MO)< Lemon(LE)< Lo tangerine(LO)< Pomelo(PO),while the rank is NO< PO<LE≈MO<LO for ABTS radical.The HPLC results reveal that the kinds and contents of the flavonoids detected in the extracts are different among the species.MO extract has the most neohesperidin dihydrochalcone of 118.76 μmol/L and quercetrin of 211.81 μmol/L of which are much more than the rest extracts.Pomelo extract has the most plentiful flavonoids of naringin with a concentration of 303.28 μmol/L.The high contents of myricetrin and dihydromyricetin which both are potent free radical scavengers may explain the highest free radical scavenging activity of the NO extract.The plasma binding rates decrease with the increasing concentrations of flavonoids,and the flavonoids having plenty hydroxyl groups on both A ring and B ring of the molecular skeleton have relative higher plasma binding rates.In addition,the plasma binding rates of flavonoids with saturated C3-C4 bond decrease significantly with the increasing concentrations.
基金This project was supported by Grant 31200884 from the National Natural Science Foundation of China Grant 2016D016, 2016-ZQN-92, and 2016-2-75 from the Natural Science Foundation of Fujian and Grant 3502Z20154048, 3502Z20144061, and 3502Z20154047 from the Natural Scien- ce Foundation of Xiamen.
文摘Background In type 2 diabetes mellitus (T2DM), high-density lipoprotein (HDL) impairs its anti-atherogenic properties and even develops to a pro-inflammatory and pro-atherogenic phenotype because of abnormal compositions and modifications. In this study, we ex- amined the effects and the related mechanisms of glycation of HDL on the proliferation and migration of vascular smooth muscle cells (VSMCs). Methods & Results Glycated HDL (G-HDL) was modified with D-glucose (25 mmol/L) in vitro. Diabetic HDL (D-HDL) was isolated from T2DM patients. Rat VSMCs were isolated from the thoracic aortas. Human VSMCs were obtained from ScienCell Research Laboratories. Alpha-actin was detected through immunofiuorescence. VSMC proliferation was assayed by Cell Count. VSMC migration was determined by transwell chamber and scratch-wound assay. Intracellular reactive oxygen species (ROS) was detected based on ROS-medi- ated 2',7'-dichlorofluorescein (DCFH-DA) fluorescence. Compared to native HDL (N-HDL), G-HDL remarkably promoted VSMC prolif- eration and migration in the dose and time-dependent manners. In addition, G-HDL enhanced ROS generation in VSMCs. However, the ROS scavenger, N-acetylcysteine, efficiently decreased ROS production and subsequently inhibited the proliferation of VSMCs induced by G-HDL. Similarly, D-HDL from T2DM patients also promoted ROS release and VSMC proliferation and migration. Conclusions HDL either glycated in vitro or isolated from T2DM patients triggered VSMC proliferation, migration, and oxidative stress. These results might partly interpret the higher morbidity of cardiovascular disease in T2DM patients.
基金Supported by the National Natural Science Foundation of China(No.31370296)the Shandong Provincial Natural Science Foundation of China(Nos.Y2007D34,ZR2011CM044)the Key Technologies R&D Program of Shandong Province of China(No.2010GNC10937)
文摘Reactive oxygen species (ROS) scavengers, including ascorbate peroxidase, superoxide dismutase, catalase and peroxidase, are the most commonly used biomarkers in assessing an organisms' response to many biotic and abiotic stresses. In this study, we cloned an 866 bp GST(phi) gene in Lemna minor and investigated its characteristics, expression and enzymatic activities under 75 lamol/L cadmium concentrations in comparison with other ROS scavengers. GST(phi) gene expression patterns were similar to those of other scavengers of ROS. This suggests that GST(phi) might be involved in responding to heavy metal (cadmium) stress and that its expression level could be used as a bio-indicator in monitoring cadmium pollution.
文摘A method for oxidative degradation of 1,4-dioxane (1,4-D) in waste water using a combination of ozone oxidation with UV irradiation (ozone/UV) treatment was investigated. The results showed that 1,4-D was degraded by ozone/UV treatment up to 90 min. The optimum concentration for the injected ozone gas was about 40 g·m^3 under a constant level of UV irradiation. Furthermore, solid phase extraction and GC-MS analysis showed no specific or reproducible peaks due to by-products of 1,4-D. It was therefore concluded that 1,4-D was completely degraded by ozone/UV treatment. In contrast, the amount of 1,4-D remaining decreased slowly in the presence of HCOf or CI. It was suggested that the degradation of 1,4-D, which results from .OH oxidation, was retarded by the presence of HCO3 or CI, which act as radical scavengers.
文摘The lethal effect produced by sunlight in bacteria depends on the photodynamic action of the ultraviolet component of the radiation. Neither the reactive oxygen species involved nor the targets for damage have been certainly identified, and the aim of this study was to address these issues. During exposures to natural sunlight, photo-protection provided by nitrogen sparging was compared with which provided by the addition of L-histidine (an efficient scavenger for hydroxyl radical and singlet oxygen) or mannitol (an hydroxyl radical scavenger which reacts poorly with singlet oxygen) to the irradiation medium. Both scavengers reproduced for the most part the effect of oxygen depletion, indicating that damage depends mainly on hydroxyl radical generation. Survival of irradiated bacteria decreased considerably when they were cultured using a substrate unsuitable for fermentation, suggesting that respiration impairment is a key factor in cell killing. This observation is in keeping with the notion that the respiratory chain is the main target for the action of sunlight in Escherichia coli.
文摘The present study investigated potential effectiveness of certain chemical candidates for controlling internal phosphorus loading, and for delineating inactivation pattern in sediment depths of an eutrophic pond under simulated mesocosm condition. Chemical administration (@ 30 mg/dm3) resulted in phosphate precipitation from water column concomitant with inactivation in sediments, under specific pH range and/or redox regime. The alum-lime combination dosing wrought the maximum reduction in orthophosphate (65.6%) and soluble reactive phosphate (71.9%) in water plus the utmost increment in sediment-P (0.257 ppm). The inactivated P forms typically exhibited a downhill concentration gradient with highest sequestration in the uppermost sediment stratum. Ironbound P displayed the highest mobility while calcium- and aluminum- bound P behaved almost immune to internal feedback dynamics. The combo-treatment was established as the most effective phosphate scavenging and confiscating agent, to be adopted as chemical remediation regime for de-eutrophication, restoration and rehabilitation of the water body.
基金supported by the National Natural Science Foundation of China(No.30572314)the Basic Research Program of Science and Technology,Ministry of Science and Technology of China(No.2007FY210500)+1 种基金the Program of Chinese Offshore Investigation and Assessment,State Oceanic Administration of China(Nos.908-01-ST12,908-02-05-04)Science and Technology Program of Shandong Province,China(No.03BS109)
文摘Seaweed Complex Preparation (SCP) is a clinical traditional Chinese medicine preparation which is composed of seven traditional Chinese herbs, and it has been used for treatment of lung cancer, liver cancer and digestive cancer. However, little infor- mation is available about the pharmacodynamic basis. The antitumor, immunomodulatory and free radical scavenging effects of SCP were evaluated in this study. Transplanted tumor in vivo method was used to determine the antitumor effect. The effects on spleno- cyte proliferation and phagocytosis of macrophages in tumor-bearing mice were measured by the MTT method and the phagocytizing cock red blood cell (CRBC) method respectively. The scavenging activities of SCP on DPPH and hydroxyl radicals in vitro were investigated. It was found that the medium-dose and high-dose of SCP could significantly inhibit the growth of transplanted hepatic tumor of murine hepatocarcinoma cell line H22, and promote proliferation of splenocytes and phagocytosis of macrophages. SCP possessed noticeable scavenging activities on DPPH and hydroxyl radicals. The antiturnor effects of SCP might be achieved by im- proving immune system and scavenging free radicals, which is in accordance with the viewpoint of traditional Chinese medicine in promoting the body resistance and eliminating pathogenic factors for cancer treatment.
文摘With the increasing interest on natural products discovery, utilization of plant parts which are commonly disregarded is another breakthrough. This study sought to determine the secondary metabolites present, phenolic contents, radical scavenging activities and antibacterial properties of 10 selected ornamental flowers which were Adenium obesum, Allamanda cathartica, Bougainvillea glabra, Catharanthus roseus, Caesalpinia pulcherrima, Heliconia subulata, Ixora coccinea, Mussaenda philippica, Tecoma stans and Torenia fournieri, from Nueva Vizcaya, Philippines. The ethanolic crude extracts were subjected to thin layer chromatography (TLC) phytochemical screening. Total phenolics expressed as mg AAE/g sample were determined through Folin-Ciocalteu method. Radical scavenging activities were measured using DPPH assay. Antibacterial activities were assessed through TLC bioautography. To quantify bacterial susceptibility of C. pulcherrima, MIC and MBC were employed in the ethyl acetate sub-fraction. TLC showed different types of phenolics, alkaloids, essential oils and terpenes. T. fournieri showed the highest total phenolics with 155 mg AAE/g while H. subulatahad showed the lowest with 3.50 mg AAE/g. Measurement of IC59 showed that H. subulata had the highest antioxidant activity followed by T. fournieri with 303 ppm and 320 ppm, respectively. H. subulata having the least amount of total phenolics had greatest radical scavenging activity. This indicates that other than phenolics, other metabolites can pose great antioxidant activities. The antibacterial testing showed that M. philippica, 1. coccinea, 1-1. subulata, C. pulcherrima and A. cathartica were bioactive against Staphylococcus aureus and Escherichia coll. MIC and MBC of C. pulcherrima ethyl acetate sub-fraction is within the range of 2.5-10 mg/mL.
文摘Functional properties of Talbina were used in ancient Arab for nutritional purpose. It was a meal made from barley flour and milk. The high antioxidant Talbina was formulated from whole flour of harley and oat, milk, date palm syrup (debis) and date palm seeds. The chemical composition, organoleptic properties and antioxidant activity of high antioxidant Talbina were determined. Sensory evaluation of traditional and high antioxidant Talbina showed that the developed product Talbina was considered as good for overall acceptability of all panelists. Also, the formulated Talbina contains high values of antioxidants components and natural nutrients. The antioxidant activity of formulated Talbina containing barley or oat may be due to presence of phenolic compounds and proanthocyanidins in the barley and oat. Increasing the antioxidant activity of high antioxidant Talbina containing barley and oat may be due to the adding of dates palm seeds which contain very high values of phenolic compounds and other antioxidants components. Date palm seeds as well as barley and/or oat give high antioxidants components which protect cells from oxidative stress and help to reduce the risk of cancer and heart disease as well as natural anti-depressant. Moreover, increasing the antioxidant activity in the formulated Talbina may play a role for reducing power, radical scavenging activity and the lipid peroxidation inhibition. In conclusion, supplementation of traditional Talbina containing barley and/or oat with date palm syrup (debis) and date palm seeds can produce simple and healthy meal to provide a good source of daily dietary antioxidants and micronutrients.
基金Supported by the Scientific and Technological Research Project of Shaanxi Province,China(No.2008K13-01)
文摘OBJECTIVE: To study the effects of Danhong injec- tion (DHI) on expression of the macrophage scaven- ger receptor 1 (MSR1) and ATP-binding cassette, sub-family A member 1 (ABCA1) genes, which en- code scavenger receptor-A I (SR-AI) and ATP-bind- ing cassette transporter 1 (ABCA1), respectively, as a potential anti-atherosclerotic mechanism. METHODS: Human U937 cells were stimulated by in- cubation with 100 nM phorbo112-myristate 13-ace- tate (PMA) for 48 h.These stimulated, monocyte-like cells were then incubated for 24 h with 50 mg/L oxi- dized low-density lipoprotein (ox-LDL, to induce foam cell formation), together with a liver X recep- tor (LXR) agonist or with different DHI concentra- tions. MSR1 and ABCA1 mRNA levels were mea- sured by fluorescence-based quantitative PCR. RESULTS: Compared with control cells (which re- ceived only ox-LDL), cells treated with both ox-LDL and 10 IJmol/L LXR agonist showed lower MSR1 ex-pression (but this effect was not statistically signifi- cant, P〉0.05) and higher ABCA1 expression (P〈 0.01). Cells that received ox-LDL and 3 mL/L DHI possessed higher MSR1 mRNA levels than the con- trols, whereas cells treated with ox-LDL and higher DHI concentrations (10, 30 or 60 mL/L) showed low- er MSR1 expression levels (but the differences ob- served between DHI concentration groups were not statistically significant, P〉0.05). ABCA1 expression in cells treated with ox-LDL and 3, 10 or 30 mL/L DHI was higher than in the control cells, and increased with increasing DHI concentration (P〈0.05). ABCA1 expression in cells treated with ox-LDL and the highest DHI concentration tested (60 mL/L) was not significantly different from that in the controls. ABCA1 mRNA levels in cells treated with ox-LDL and DHI were similar to, or lower than, those in cells treated with ox-LDL and the LXR agonist. CONCLUSION: DHI does not affect MSR1 mRNA lev- els in ox-LDL-treated U937 cells. However, at certain concentrations (10 and 30 mL/L), DHI significantly increases ABCA1 mRNA levels. Therefore, the an- ti-atherosclerotic action of DHI might be mediated by an increased expression of ABCA1.
基金supported by the National Natural Science Foundation of China(Grant Nos.21307101 and 21301015)the Science & Technology Department of Sichuan Province(Pillar Program)(Grant No.2013FZ0060)+1 种基金Education Department of Sichuan Province(Grant No.15ZA0392)the Project of Postgraduate Degree Construction,Southwest University for Nationalities(Grant No.2015XWD-S0703)
文摘Fenton reaction based on Fe2+-H2O2 system has been widely applied in water remediation, but the obvious drawbacks largely hinder its practical uses. Alternatively, heterogeneous nanomaterials with proper surface modification could be used as Fenton-like catalysts. Surface doping of Ti O2 could concentrate the pollutants surrounding the Fe3O4 catalyst, which might benefit the catalytic performance of Fe3O4. Herein, we reported that Ti O2-doped Fe3O4 nanoparticles(NPs) could be used as high-performance Fenton-like catalyst for dye decoloration in near neutral environment, where the doping of Ti O2 on Fe3O4 surface dramatically improved the catalytic activity of Fe3O4 in Fenton-like reaction. Ti O2-doped Fe3O4 NPs catalyzed the decomposition of H2O2 to oxidize methylene blue without external energy supply, resulting in effective decoloration. Ti O2-doped Fe3O4 NPs showed high catalytic activity under various p H values and even in the presence of radical scavenger. More catalysts and H2O2 would facilitate the decoloration. At higher temperature, the decoloration became faster and more effective. The implication to the environmental applications of Ti O2-doped Fe3O4 NPs is discussed.