不同环境下邻氨基酚及邻苯二酚衍生物捕获自由基性能研究

通过研究清除ABTS+·自由基实验,对其IC50进行比较,分析分子结构和环境因素影响邻氨基酚和邻苯二酚及其衍生物的抗氧化性抗氧化活性的规律。结果发现,邻氨基酚及其衍生物清除自由基能力强于标准抗氧化剂BHT,在冰醋酸环境,清除自由基能力基本不变,吡啶环境,增强清除自由基能力。     

丹皮酚衍生物抗氧化活性研究

以丹皮酚和有机胺以及多种金属化合物为主要原料,合成11种丹皮酚衍生物。通过DPPH.分析法,研究了目标产物的抗氧化性。结果表明,目标产物有一定抗氧化活性,但清除自由基能力都比较弱。     

缓蚀剂文摘

缓蚀剂文摘９７－２１邻苯二酚衍生物作溶液中铝的强力缓蚀剂在盐酸溶液中，用化学法和电化学法研究了某些邻苯二酚衍生物抑制铝腐蚀的缓蚀效率。用上述两种方法发现所研究的化合物具有相同的缓蚀效率。极化数据显示，在阴极极化和阳极极化过程中，所有缓蚀剂具有混合型缓...     

罗地亚在中国建联苯酚装置

罗地亚（Rhodia）将投资3500万美元，在上海附近建设一套联苯酚装置，产能1．2万t／a．2007年初建成。新装置将生产联苯酚、邻苯二酚和氢化醌。罗地亚在上海有三座工厂，生产联苯酚衍生物。在无锡与日本宇部合资生产邻苯二酚衍生物邻甲氧基苯酚及香精和香料组分异冰片基环己醇（IBCH）。     

用相转移催化法制取邻-二丁氧基苯和邻-二异丁氧基苯

<正> 一、引言邻二烷氧基苯或称邻苯二酚醚类是一类有用的合成中间体,可用于天然产物、香料、药物、液晶的合成以及橡胶抗氧剂、高分子聚合终止剂、钻井泥浆稳定剂等制造。近年来发展的一类喹啉型抗球虫饲料添加剂如保喹乐(Buquinolate)、敌可昆(Decoquinate)等均是邻苯二酚醚类的衍生物。因此研究其合成方法,在当前具有相当重要的意义。制取邻苯二酚醚类通常以邻苯二酚为原     

邻苯二酚的生产与发展

邻苯二酚俗称几茶酚或焦尔茶酚,它以多种衍生物的形式存在于自然界中,是重要的精细化工原料,广泛应用于农药、医药、香料、染料、感光材料及橡胶等行业。 一、生产工艺 邻苯二酚的合成工艺很多,目前国内外工业生产所采用的方法主要有以下三种。     

龙眼核中总黄酮含量测定及其抗氧化性研究

对龙眼核中的总黄酮含量和抗氧化性进行了研究,结果表明,龙眼核中黄酮类物质质量分数为1.21%;龙眼核中黄酮类物质对清除自由基有明显作用,且黄酮类物质的添加量在试验范围内与其抗氧化性呈正相关。     

槐花米中芦丁的抗氧化性及抑菌性研究

目的:研究槐花米中芦丁的抗氧化性及抑菌性。方法:以中药槐花米为原料,采用碱溶酸沉法提取其中的芦丁并精制,对精制物进行红外光谱分析;采用清除羟基自由基能力测定来分析研究芦丁的抗氧化性;采用滤纸片法以大肠杆菌和金黄色葡萄球菌为抑菌对象,分析芦丁的抑菌性。结果:芦丁浓度越高抗氧化性越强,芦丁的抗氧化性优于抗坏血酸;芦丁对大肠杆菌和金黄色葡萄球菌均有抑菌作用。结论:芦丁有较好的抗氧化性和抑菌性。     

正交试验优化黑米原花青素的提取工艺及其抗氧化性研究

用溶剂提取法提取黑米中的原花青素。通过正交试验，得到黑米中原花青素的最佳提取条件为：丙酮体积分数60%、提取时间60 min、料液比1∶35(g∶mL)、提取温度55℃,黑米原花青素提取率是0.531 2%,纯度为60.15%。采用DPPH清除能力和·OH清除能力衡量黑米中原花青素的抗氧化性，试验表明，黑米中的原花青素可以有效清除DPPH和·OH,提取的原花青素有较好的抗氧化性。     

吩嗪的合成及其应用

介绍了吩嗪合成的2-氨基或硝基二苯胺关环反应、邻苯二胺和邻苯二酚缩合反应等主要几种方法。叙述了吩嗪衍生物在医药、农药、染料、有机导电体和太阳能电池等方面有广泛的用途。     

葡萄籽发酵液抗衰老活性研究

利用乳酸菌发酵葡萄籽得到葡萄籽发酵液。对发酵液中的主要活性成分进行检测,通过测定自由基清除效果以及成纤维细胞增殖实验来衡量发酵液的抗衰老活性。结果表明葡萄籽发酵液中蛋白质、黄酮、原花青素的含量分别为2.89,1.01,0.43 mg/m L。体积分数为0.43%和1.25%的发酵液可清除50%的ABTS自由基和DPPH自由基;发酵液原液对羟自由基的清除率为40%,对铁离子的还原能力表示为2 073.43μmol Trolox/L。     

7种茶氨酸类似物的合成及清除自由基活性

以L-谷氨酸为起始原料,经邻苯二甲酸酐保护、酰化开环、肼解脱保护等反应合成了7种茶氨酸类似物,结构经EA、IR、1HNMR、13CNMR和MS进行了确认,并测定了其清除DPPH自由基和羟自由基活性。结果表明:2-氨基-5-氧代-5-[(4-羟基苯基)氨基]戊酸清除自由基活性最强,0.002 mol/L时清除DPPH自由基率为90%,0.004 mol/L时清除羟自由基率达95%;2-氨基-5-氧代-5-[(4-氨基苯基)氨基]戊酸次之。由此可见,茶氨酸类似物中5位连有苯基或所连苯基对位有供电子基团时,可提高其清除DPPH自由基和羟自由基活性,且随对位所连基团供电性的提高,清除活性增强。     

中华猕猴桃水提液清除羟自由基以及抑制酪氨酸酶活性的研究

以Fenton反应产生羟自由基,测定中华猕猴桃水提液清除羟自由基的能力。以L-酪氨酸和L-多巴为底物,测定中华猕猴桃水提液对酪氨酸酶单酚酶和二酚酶活力的影响以及抑制动力学。实验结果表明:中华猕猴桃水提液对羟自由基有较好的清除作用,当水提液质量浓度为1.0 g/L时,羟自由基清除率达到了95.57%。中华猕猴桃水提液对酪氨酸酶单酚酶和二酚酶的活性均有较好的抑制作用,其半数抑制浓度(IC_(50))分别为0.28和0.35 g/L。动力学研究表明,中华猕猴桃水提液对酪氨酸酶二酚酶的抑制作用属于可逆过程,其抑制作用表现为混合型抑制。     

Antioxidant activity and characterization of bioactive polypeptides from bovine hair

The antioxidant activity and food protection effect of bioactive polypeptides from bovine hair were investigated. In various in vitro tests, polypeptides showed a strong reducing power and a remarkable antioxidant capability to scavenge free radicals (ABTS, superoxide and hydroxyl radicals). Moreover, polypeptides also exhibited a significant food protection effect to inhibit the oxidation of edible oil by controlling the peroxide value (POV). Furthermore, by using gel filtration chromatography (GFC), high performance size exclusion chromatography (HPSEC), amino acid analysis and atomic force microscopy (AFM), an antioxidant polypeptide (APB) was purified and characterized with a molecular weight of 18.7 KDa in the form of spherical lumps, which was composed of 17 kinds of amino acids and contained sulfydryl group. Our results suggested that the antioxidant polypeptide from bovine hair could be a new potential source for preparing natural antioxidant applied in oil or oil-rich food.     

吡嗪-噁唑联芳类化合物的合成及其抗氧化性能

为了从吡嗪和噁唑类化合物中寻找新的抗氧化剂，本文采用FeCl3催化吡嗪-N-氧化物和噁唑化合物发生氧化偶联反应，合成了3个吡嗪-噁唑联芳类化合物。采用1HNMR、13CNMR和MS对目标化合物的结构进行了表征；通过抑制自由基引发的DNA氧化反应及淬灭自由基反应体系对化合物的抗氧化活性和还原能力进行了测试。结果表明，3个目标化合物能够有效地抑制自由基引发的DNA氧化反应并捕获自由基，具有较强的自由基清除能力和还原能力，是一类潜在的抗氧化剂。其中，在抑制2,2''-偶氮二异丁基脒二盐酸盐(AAPH)引发的DNA氧化反应体系中，3个吡嗪-噁唑联芳类化合物的有效计量因子(n)分别为1.48、1.78和1.88; 在抑制HO?和还原型谷胱甘肽自由基(GS?)引发的DNA氧化反应体系中，3个化合物相对空白硫代巴比妥酸活性物质(TBARS)吸光度百分数分别为76.1%和68.3%、69.8%和64.1%及72.6%和67.4%；3个化合物均能够捕获2,2''-偶氮-双-(3-乙基苯并噁唑啉-6-磺酸)二铵盐自由基(ABTS ?)和二苯苦味酰肼自由基(DPPH?)。     

葛根素的基础研究与临床应用新进展

葛根素是中药葛根的主要有效成分之一。实验证明有清除氧自由基，抗氧化性损伤，扩张心脑血管和降低心肌氧耗等多种作用，临床主要用于防治心脑血管疾病。本文就近年来葛根素的药理学及其临床应用的最新进展进行了综述。     

Synthesis and Characterization of Monodispersed Copper Colloids in Polar Solvents

A chemical reduction method for preparing monodispersed pure-phase copper colloids in water and ethylene glycol has been reported. Owing to the reduction property of ethylene glycol, the reaction rate in ethylene glycol is higher than that in water. In addition, the amount of reducing agent can be reduced largely. Ascorbic acid plays roles as reducing agent and antioxidant of colloidal copper, due to its ability to scavenge free radicals and reactive oxygen molecules. Thermogravimetric results reveal that the as-prepared copper nanoparticles have good stability, and they begin to be oxidized at above 210 °C. Polyvinyl pyrrolidone works both as size controller and polymeric capping agents, because it hinders the nuclei from aggregation through the polar groups, which strongly absorb the copper particles on the surface with coordination bonds.     

一种吲哚基姜黄素类似物的合成及其抗氧化活性研究

吲哚-3-甲醛与2-羟基-5-甲氧基苯乙酮进行羟醛缩合反应,生成一种吲哚基姜黄素类似物1-(2-羟基-5-甲氧基苯基)-3-(3-吲哚基)-2-烯-1-酮,在不同的催化剂、温度、溶剂等条件下,探索研究合成反应所需的最优工艺条件,采用合适的方法分离提纯得到纯净产品。通过熔点测定、氢核磁共振分析法、质谱分析法等对合成产物进行分析,并研究其抗氧化生物活性。结果表明,该化合物均具有清除DPPH自由基、羟基自由基的能力,表现出明显的抗氧化活性。     

Seasonal Variation of Chemical Composition and Antioxidant Activity of Essential Oil from <Emphasis Type="Italic">Pistacia atlantica</Emphasis> Desf. Leaves

The composition and antioxidant activities of Pistacia atlantica Desf. essential oil were investigated. Qualitative and quantitative differences in compositions and in antioxidant activities of male and female leaf essential oils were observed during the season. The essential oils obtained by hydrodistillation were analysed by GC and GC–MS. The oils were rich in monoterpenes hydrocarbons and oxygenated sesquiterpenes. The main components of male essential oil were α-pinene/α-thujene, spathulenol and bicyclogermacrene. The major component of female essential oil was δ-3-carene. The seasonal variation showed that most of the main components of the oils reached theirs highest values in September. The antioxidant activity of the oil was investigated in vitro using two assays: DPPH^· (2,2-di-phenyl-1-picrylhydrazyl) free radical-scavenging and FRAP (Ferric Reducing Antioxidant Power). The highest antioxidant capacity to scavenge free DPPH radicals was reached in the month of June for male oils and during the months of September–October for the female oils. The high reducing power for male oil was observed during the month of June and for the female oil it was in August. The female oil was more active than the male oil. The antioxidant capacity of the female oil was almost ten times higher than Ascorbic acid in the FRAP assay.     

Free-Radical-Scavenging Effect of Carbazole Derivatives on DPPH and ABTS Radicals

The major objective was to measure the trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) equivalent antioxidant capacity (TEAC) of carbazole derivatives (Ar₂NHs) by means of scavenging 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS^+·). The Ar₂NHs included phenoxazine (PozNH), phenothiazine (PtzNH), iminostilbene (IsbNH) and diphenylamine (DpaNH), and the TEAC of trolox, α-tocopherol (TocH), l-ascorbic acid (VC) and l-ascorbyl-6-laurate (VC-12) were measured as well. The TEAC results revealed that the ability to scavenge DPPH (PozNH > IsbNH ~PtzNH ~TroH ~TocH ~VC ~VC12), differed from the ability to scavenge ABTS⁺ (PtzNH > IsbNH > PozNH > DpaNH ~TroH ~TocH ~VC ~VC12). CazNH did not react with DPPH and ABTS^+·. Furthermore, the addition of acetic acid accelerated the reaction rate of Ar₂NH to scavenge DPPH, suggesting that a sequential proton loss electron transfer (SPLET) mechanism occurred with amine-type antioxidants during the trapping of DPPH. In contrast, the addition of acetic acid or pyridine reduced the reaction rate of Ar₂NH to scavenge ABTS^+., suggesting that the hydrogen atom transfer (HAT) mechanism is the basis for the reaction that is occurring.