Antioxidant capacity of robust polyaniline–ethyl cellulose films

Ethyl cellulose films containing up to 17% polyaniline (PANI EC film) were prepared from ethanolic solutions. The antioxidant capacity of the PANI EC films was examined using the oxygen radical absorbance capacity (ORAC) assay, and the films demonstrated very efficient peroxyl free radical scavenging activity. A good correlation was also obtained between the net ORAC curve area and the size of the tested film, indicating the homogenous dispersion of active PANI powder across the film. Reduced PANI presented greater peroxyl radical scavenging activity than more oxidized as-prepared forms. The influence of the PANI EC films on the oxidation of Ropufa oil was determined after incubation at 60 °C for several days. The oil stored in the presence of a PANI EC film was found to exhibit a lower peroxide value than in the absence of PANI, indicating that the conducting polymer can inhibit the oxidation of fish oil.     

Mulberry Seed Oil: a Rich Source of δ‐Tocopherol

In the present study, mulberry seed oil (MSO) samples obtained from seeds of different mulberry varieties as well as concentrated mulberry juice production waste (mulberry pomace) were investigated. Radical scavenging capacity, tocopherol and total phenolic content of MSO were determined. It was observed that MSO contain unique amounts of δ‐tocopherol varying between 1645–2587 mg kg^?1 oil depending on the variety. The secondary tocopherol homologue was γ‐tocopherol within a concentration range of 299–854 mg kg^?1 oil. MSO exhibited a very high antioxidant capacity varying in the range of 1013–1743 and 2574–4522 mg α‐tocopherol equivalents (α‐TE) per kg of oil for 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and freeze‐dried 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) (FD‐ABTS) radical cation assays, respectively. Both antioxidant capacity and total phenolic content were higher for mulberry pomace oil compared with the seed oils. Fatty acid composition of MSO was also determined, and linoleic acid was found to be the primary fatty acid (66–80 %).     

Gelatin hydrolysate powder from the scales of spotted golden goatfish: Effect of drying conditions and juice fortification

Effects of different spray drying temperatures (inlet temperatures of 160, 180, and 200°C) on characteristics, bioactivity, and sensory properties of gelatin hydrolysate from spotted golden goatfish scales using maltodextrin as a carrier agent were investigated. The yield of gelatin hydrolysate powder was higher, when inlet temperature increased (p?p?p?p?相似文献   

核桃仁抗氧化活性研究

采用清除二苯代苦味肼基(DPPH)自由基、清除[2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)二氨盐](ABTS)自由基及铁离子还原/抗氧化能力(FRAP)测定法,对核桃仁提取物进行抗氧化活性评价,并与阳性对照没食子酸丙酯(PG)、丁基羟基茴香醚(BHA)和二丁基羟基甲苯(BHT)进行比较。在核桃仁提取物中,乙酸乙酯提取物清除DPPH和ABTS自由基的能力(IC50值分别为1.58 mg/L和1.69 mg/L)强于BHA(IC50值分别为3.43 mg/L和1.72 mg/L)和BHT(IC50值分别为18.79 mg/L和6.04 mg/L),弱于PG(IC50值分别为0.86 mg/L和0.66 mg/L);乙酸乙酯提取物还原Fe3+的能力最强〔FRAP值为(13212.99±55.35)μmol TE/g〕,强于PG〔FRAP值为(10617.75±138.38)μmol TE/g〕、BHA〔FRAP值为(7383.10±121.08)μmol TE/g〕和BHT〔FRAP值为(1748.49±3.46)μmol TE/g〕;核桃仁正丁醇提取物清除DPPH和ABTS自由基的能力(IC50值分别为4.94和1.90 mg/L)以及还原Fe3+的能力〔FRAP值为(2299.99±27.68)μmol TE/g〕强于BHT。结果表明,核桃仁乙酸乙酯和正丁醇提取物都具有很好的抗氧化活性,且乙酸乙酯提取物活性强于正丁醇提取物。     

粘毛蓼的抗氧化活性

用清除二苯代苦味酰基(DPPH)自由基、清除[2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)二氨盐](ABTS)自由基和铁离子还原/抗氧化能力(FRAP)测定法,对粘毛蓼体外总抗氧化活性进行了评价,结果与6-羟基-2,5,7,8-四甲基苯并二氢吡喃-2-羧酸(Trolox)及阳性对照丁基羟基茴香醚(BHA)、二丁基羟基甲苯(BHT)比较发现,粘毛蓼提取物有很好的体外抗氧化活性。乙酸乙酯提取物清除DPPH自由基(IC50=7.89 mg/L)的能力比BHT清除能力(IC50=18.71 mg/L)强,比BHA(IC50=3.20 mg/L)清除能力略弱;清除ABTS自由基能力(IC50=6.67 mg/L)比BHT(IC50=7.72 mg/L)清除能力强,比BHA(IC50=1.88 mg/L)清除能力弱;还原Fe3+的能力〔FRAP=(1362.55±47.22)μmol TE/g〕比BHT〔FRAP=(1581.68±97.41)μmol TE/g〕略低。在3种提取物中,乙酸乙酯提取物具有最高的抗氧化能力,甲醇提取物次之。3种方法中,DPPH方法和ABTS方法相关性最高(R=0.993)。     

开封产3种白色菊花提取物的抗氧化活性

采用清除二苯代苦味肼基(DPPH)自由基、清除[2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)二氨盐](ABTS)自由基及铁离子还原/抗氧化能力(FRAP)测定法,对开封产的3种白色菊花(兼六香白、国华万胜及白玉带)不同溶剂提取物的体外抗氧化活性进行了评价,将所测定结果与水溶性维生素E(6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid,Trolox)及阳性对照二丁基羟基甲苯(BHT)进行了比较。结果表明,3种菊花的不同溶剂提取物抗氧化活性不同。同一种菊花的甲醇提取物具有很好清除DPPH自由基和还原铁离子的能力,而石油醚提取物几乎无活性。菊花的3个品种中,兼六香白和国华万胜的抗氧化活性较好,其活性远远超过白玉带的抗氧化活性。9个提取物中,兼六香白的甲醇提取物总的抗氧化活性最好。它对DPPH自由基的清除能力(IC50值为20.49 mg/L)比BHT(IC50值为18.92 mg/L)作用略低;其还原Fe3+的能力(FRAP值为731.73±1.77μmol TE/g)比BHT(1 581.68±97.41μmol TE/g)作用低1/2。3种方法测定结果基本一致,其中以DPPH法和FRAP法相关性最好(R=0.982 0)。     

苍术及其麸炒品抗氧化活性研究

采用清除二苯代苦味酰基(DPPH)自由基、清除[2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)]二氨盐(ABTS)自由基和铁离子还原/抗氧化能力(FRAP)测定法对其挥发油和不同提取物进行抗氧化活性的研究。结果表明,生苍术乙酸乙酯提取物具有很好的抗氧化活性(DPPH方法:IC50=6.03μg/mL;ABTS方法:IC50=3.59μg/mL;FRAP方法:FRAP值=3186.67μmolTE/g),麸炒之后,其抗氧化活性显著下降。因而苍术抗氧化应生用。     

拳参抗氧化活性研究

用清除二苯代苦味酰基（DPPH）自由基、2,2’-连氨-（3-乙基苯并噻唑啉-6-磺酸）二氨盐（ABTS）自由基和铁离子还原／抗氧化能力（FRAP）测定法对拳参体外总抗氧化活性进行评价．并与6-羟基-2,5,7,8-四甲基苯并二氢吡喃-2-羧酸（Trolox）及阳性对照二丁基羟基甲苯（BHT）比较。发现拳参有较好的体外抗氧化活性。甲醇提取物清除DPPH自由基（IC50=3．81μg／mL）的能力远远强于BHT的清除能力（IC50=18．71μg／mL）;清除ABTS自由基能力（IC50=7．65μg／mL）强于BHT（IC50=7．72μg／mL）的清除能力;还原Fe^3＋的能力（FRAP=2009．51±16．44μmol TE／g）最强,强于BHT（FRAP=1581．68±97．41μmol TE／g）。在3种提取物中,甲醇提取物具有最高的抗氧化能力,乙酸乙酯提取物次之。3种方法中,ABTS方法和FRAP方法相关性（R=0．984）最高。     

珍珠菜的抗氧化活性

用清除二苯代苦味肼基自由基、清除2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)自由基和铁离子还原/抗氧化能力测定法,分析了珍珠菜提取物总的抗氧化作用。在珍珠菜提取物中,甲醇提取物清除二苯代苦味肼基自由基能力(IC50值为12.28mg/L)比阳性对照BHT作用强(IC50值为18.79mg/L);甲醇提取物对清除2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)自由基能力(IC50值为7.52mg/L)比BHT(IC50值为6.04mg/L)清除能力略低;甲醇提取物还原Fe3+的能力(FRAP值为1179.40±46.70μmolTE/g)比BHT(FRAP值为1748.49±3.46μmolTE/g)略低。珍珠菜3种提取物中,甲醇提取物具有较高的抗氧化能力。该文报告工作的新颖性,已为河南省医学情报研究所2008年5月30日出具的第2008113号《科技查新报告》所证实。     

Antioxidant Capacity of Rapeseed Extracts Obtained by Conventional and Ultrasound‐Assisted Extraction

Ultrasound‐assisted extraction (UAE) and conventional solid–liquid extraction were applied to extract total antioxidants from two rapeseed varieties. The antioxidant capacities (AC) of winter and spring rapeseed cultivars were determined by four different analytical methods: ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2′‐azino‐bis‐3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS). The average AC of the studied rapeseed cultivars ranged between 4.21–10.03 mmol Trolox (TE)/100 g, 7.82–10.61 mmol TE/100 g, 8.11–51.59 mmol TE/100 g, 22.48–43.13 mmol TE/100 g for FRAP, CUPRAC, DPPH and ABTS methods, respectively. There are positive correlations between total phenolics (TPC = 804–1625 mg sinapic acid (SA)/100 g) and AC of the studied rapeseed extracts (r = 0.2650–0.9931). Results of the principal component analysis (PCA) indicate that there are differences between the total amounts of antioxidants in rapeseed samples extracted by different extraction techniques. Rapeseed extracts obtained after 18 min of ultrasonication revealed the highest content of total antioxidants. The UAE is a very useful, efficient and rapid technique of oilseed samples preparation for determination of AC by different analytical methods.     

Electrically conducting biodegradable polymer composites (polylactide‐polypyrrole and polycaprolactone‐polypyrrole) for passive resonant circuits

Electrically conducting biodegradable polymer composites made of polypyrrole (PPy) nanoparticles embedded in poly(L ‐lactide) (PLLA) or poly(ε‐caprolactone) (PCL) are prepared by chemical oxidative polymerization. They will be used as electrical conductors for fabricating biodegradable passive resonant circuits for bioimplants. For both composites, the conductivity exhibits a percolation threshold at ～6 wt% of PPy. Several reactants are tested, the polymerization process resulting in the highest conductivity uses iron(III)chloride hexahydrate (FeCl₃), sodium dodecyl benzene sulfonate, and p‐nitrophenol (pNPh), for both poly(L ‐lactide)‐polypyrrole (PLLA‐PPy) and poly(ε‐caprolactone)‐polypyrrole (PCL‐PPy). Conductivities of 2.7 ± 0.8 S cm^ε1 (PLLA‐PPy) and 7.8 ± 2.3 S cm^?1 (PCL‐PPy) are reached for a PPy content of 40 wt%. The PPy particle, observed by SEM, forms agglomerates having a size of 0.6–3.5 μm. The samples have similar PPy particle distributions over the entire cross sections. The conductivity as a function of time is investigated, being 34–70% of the initial value for samples stored in nitrogen, whereas it is less than 1% for samples stored in body‐like conditions, bringing the conclusion that a biodegradable packaging will be required to protect the resonant circuits from body fluids. Finally, the biocompatibility of the polymer composites is evaluated with cytocompatibility tests on dermal human fibroblast cells, showing promising results in particular for composites having a low PPy content. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Evidence for ‘bottom up’ growth during vapor phase polymerization of conducting polymers

Elemental analysis of sequentially formed PPy/PEDOT polymer blends using liquid-like oxidant layers by vapor phase polymerization (VPP) has provided conclusive evidence for a ‘bottom up’ growth mechanism during polymerization. Chemical analysis by XPS of the top surface of the polymer thin film formed by sequential polymerization of pyrrole monomer, followed by EDOT monomer, revealed the outer most layer to be PEDOT. ToF-SIMS depth profiling confirmed this result, indicating the diminishing presence of PEDOT fragments with concomitant increasing PPy fragments as a function of depth from the top surface, an indication that PEDOT was stationed above PPy. When the polymerization process was reversed (i.e. EDOT followed by pyrrole) the opposite was observed. By extension we propose that the same growth mechanism exists for any VPP conducting polymer where a (viscous) liquid-like oxidant layer is utilized.     

Effects of the addition of ultrasound‐pulsed gelatin to chitosan on physicochemical and antioxidant properties of casting films

This study investigated the performance of chitosan based films with added, high‐intensity ultrasound‐pulsed, gelatins (42, 52, 71 and 84 W cm^?2). The mechanical, structural, chemical and antioxidant properties were investigated, to evaluate the potential of ultrasound as a technique to improve film properties. The tensile strength and elastic modulus of films containing ultrasound‐pulsed gelatins showed a significant increase, while the elongation parameter showed a significant decrease. Micrographs showed that all films presented agglomerations. The infrared spectra of the films displayed characteristic shifts in the chitosan and gelatin spectra, which may be the result of hydrogen bridge interactions and electrostatic interactions between the two polymers. The antioxidant capacity was analyzed through the ferric reducing antioxidant power (FRAP) assay and the 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid) (ABTS) assay of films and showed that gelatins treated with higher acoustic intensity had improved antioxidant capacity. High‐intensity ultrasound‐treated gelatin enhanced the strength, elasticity and antioxidant properties of the chitosan based films. © 2020 Society of Chemical Industry     

Antioxidant activity and free radical‐scavenging capacity of ethanolic extracts of thyme,oregano, and marjoram

Phenolic compounds were extracted from thyme (Thymus vulgaris L.), oregano (Origanum vulgare L.) and marjoram (Origanum majorana L.) with 95% ethanol. A number of antioxidant and radical‐scavenging capacity tests were performed on the prepared extracts using colorimetric assays and model system studies. Specifically, these included determining the content of total phenolics, antioxidant efficacy in a linoleic acid‐ferric thiocyanate model system, reducing power, scavenging effect on 2,2'‐diphenyl‐1‐picrylhydrazyl radical, and hydroxyl radical‐scavenging activity by electron paramagnetic resonance spectroscopy. Moreover, the efficacies of the prepared herb extracts were investigated in a real‐life food product: the stabilization of butter against oxidation.     

Antioxidant Activity of Subcritical Water Extracts from Chaga Mushroom (Inonotus obliquus)

The subcritical water (SCW) extraction of Chaga mushroom (CM) was carried out at various temperatures (50, 100, 150, 200, 250, and 300°C) and times (10, 30, and 60 min), and then antioxidant activities of the SCW extracts were evaluated by determining 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, reducing power (RP), superoxide dismutase (SOD)-like activity, and total phenol content (TPC). The DPPH and ABTS radical scavenging activities, and the SOD-like activity of the extracts increased with elevated temperatures and times. For example, DPPH and ABTS radical scavenging activities, and SOD-like activity of the extracts at 250°C for 60 min were 72.5, 97.8, and 92.3%, respectively, while those at 50°C for 60 min were 63.2, 14.4, and 22.6%, respectively. However, the activities decreased at 300°C. The highest TPC and RP were found at 250°C for 30 min with values of 10.724 mg/mL and 1.063 optical density, respectively. These results indicate that SCW extraction was significantly effective on the increase of antioxidant activity of the CM.     

酒糟总氨基酸、总多酚、多糖含量测定及抗氧化活性研究

酿酒行业每年都会产生大量酒糟,为减少酒糟的丢弃浪费与环境污染,研究酒糟内总成分含量、总抗氧化能力,可为后期开发利用提供理论支持。研究采用茚三酮法、福林酚法、苯酚-硫酸法测定酒糟内总氨基酸、总多酚、多糖含量,同时采用1,1-二苯基-2-三硝基苯肼(1,1-Diphenyl-2-trinitrophenylhydrazyl,DPPH)法、2,2′-联氮双-(3-乙基苯并噻唑林-6-磺酸)二胺盐[2,2′-Azinobis(3-ethylbenzothi azoline-6-sulfonic acid)ammonium salt,ABTS]法、超氧阴离子(Superoxide anion,O^-₂)法测定酒糟液不同稀释倍数抗氧化能力。谷物酿酒后的副产物中总氨基酸、总多酚、多糖平均含量分别达到9.7998、0.6289、2.8203 mg/mL,对DPPH、ABTS、O^-₂的自由基清除率均达到90%以上。酒糟液富含大量氨基酸、多酚、多糖,有较强抗氧化能力,可开发为新型产品,为企业带来下游效益的同时减轻环境污染,为后续高效利用酒糟液奠定基础。     

The characterization of polyaniline and polypyrrole composites by pyrolysis mass spectrometry

In this work, direct insertion probe pyrolysis mass spectrometry technique was applied to investigate the thermal and structural characteristics of electrochemically prepared polyaniline (PANI), polypyrrole (PPy), and their composites/copolymers synthesized either by electrochemical polymerization of pyrrole on PANI‐coated electrode (PANI/PPy) or by coating PANI on PPy (PPy/PANI) in H₂SO₄ solutions. It has been determined that the polymer first coated on the electrode degraded to a certain extent during the polymerization of the second. The extent of degradation was greater for PPy and increased with the increase in acid concentration. On the other hand, the detection of mixed dimers confirmed copolymer formation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

红豆越橘花青素与金银花多酚协同抗氧化活性

探讨了红豆越橘花青素和金银花多酚对DPPH自由基、ABTS自由基、羟基自由基、超氧阴离子自由基的清除及铜离子还原能力和总还原能力的协同抗氧化活性.测定单一组分和复配物〔分别以红豆越橘花青素与金银花多酚按质量比5:1、2:1、1:1、1:2、1:5进行复配,记为复配物(5:1)、(2:1)、(1:1)、(1:2)、(1:5),下同〕抗氧化活性,计算联合作用指数(CI),分析复配物是否具有协同抗氧化作用.结果显示,除复配物(1:5)在清除DPPH自由基上表现为拮抗作用外,其他比例复配物在各项指标中均表现出协同效果.其中,复配物(2:1)对DPPH自由基和铜离子还原能力的CI值分别为0.59±0.07和0.35±0.03,表明二者以质量比2:1复配后对DPPH自由基的清除和铜离子还原能力起到协同作用;复配物(1:1)对ABTS自由基和总还原能力对应的CI值分别为0.58±0.04和0.33±0.04,表明复配后,对ABTS自由基清除及总还原能力具有协同抗氧化作用.红豆越橘花青素和金银花多酚复配具有很强的抗氧化协同功效.     

Synthesis of nitropyridine‐based π‐conjugated polymers and their chemical properties

π‐Conjugated poly(3‐nitropyridine‐2,5‐diyl) ( PPy‐3‐NO₂ ), poly(3,3′‐dinitro‐2,2′‐bipyridine‐5,5′‐diyl) ( PBpy‐3,3′‐diNO₂ ), and a poly(arylene ethynylene) type polymer consisting of a 3,3′‐dinitro‐2,2′‐bipyridine unit ( PAE‐1 ) were synthesized by Cu‐promoted Ullmann coupling reaction and Pd‐catalyzed coupling reaction. PPy‐3‐NO₂ and PAE‐1 were soluble in organic solvents such as DMSO, DMF, and chloroform, and gel permeation chromatography analysis showed a number average molecular weight (M_n) of 9,300 and 12,300, respectively. PPy‐3‐NO₂ gave intrinsic viscosity, [η], of 0.53 dL g^?1 in DMF. PBpy‐3,3′‐diNO₂ had somewhat lower solubility. The polymers exhibited a UV–vis peak at about 430 nm. PPy‐NO₂ received electrochemical reduction at ?1.5 V versus Ag⁺/Ag in acetonitrile, and gave an electrochemical redox cycle in a range from 0 to ?1.1 V versus Ag⁺/Ag in an aqueous solution. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1763–1767, 2006