姜黄素的抗氧化机制及以其为先导物的抗氧化化合物研究进展

姜黄素具有抗氧化、抗肿瘤、抑菌等多种药理活性。近年来为开发姜黄素类抗氧化剂,国内外研究者设计和合成了大量姜黄素衍生物。本文介绍了姜黄素及其衍生物的抗氧化机制,重点概述基于抗氧化的姜黄素抗氧化衍生物的研究进展。     

壳聚糖及其衍生物的抗氧化性能及应用研究进展

对壳聚糖及其衍生物的抗氧化性能和应用进行综述。壳聚糖的抗氧化功能主要受其分子质量和脱乙酰度的影响;壳聚糖的醚化、酯化、酰化衍生物及金属配合物影响其抗氧化性能;壳聚糖及其衍生物在水果保鲜、果汁澄清和防褐变、食物保存、延缓衰老等方面具有广阔的应用前景。     

蛋白质及其衍生物的抗氧化性能

详细讨论了蛋白质、酶、多肽、氨基酸及其衍生物的抗氧化性能，抗氧化机制和影响因素。     

黄芩苷结构修饰及抗氧化构效关系

为了评价黄芩苷中糖链结构的变化对其抗氧化作用的影响,进一步探讨黄芩苷抗氧化构效关系。采用化学合成法对黄芩苷糖链部分的6- 羧基进行选择性酯化修饰,通过薄层层析(TLC)和核磁共振(13C NMR)波谱法确定它们的结构。并采用超快速抗氧化自由基全自动分析仪测定黄芩苷及其衍生物的抗氧化活性。对黄芩苷糖链结构的6- 羧基进行酯化,合成了黄芩苷乙酯(2)、丁酯(3)和苄酯(4)衍生物。黄芩苷的抗氧化活性强于其衍生物,说明6- 羧基为黄芩苷抗氧化活性所必需基团。     

壳聚糖及其衍生物抗氧化活性的研究

以壳聚糖、羧甲基壳聚糖和盐酸壳聚糖为材料,研究3种壳聚糖及其衍生物对DPPH自由基、超氧阴离子自由基和羟自由基的清除能力以及还原能力和抗脂质氧化能力,并通化曲线拟合方法明确壳聚糖及其衍生物的IC50值。结果表明,随着浓度的增加,壳聚糖及其衍生物的抗氧化活性逐渐增强。3种壳聚糖及其衍生物中壳聚糖的抗氧化活性最强,其对DPPH自由基、超氧阴离子自由基和羟自由基的半清除率IC50值分别为0.91、4.87、0.28 mg/m L。     

黄原胶琥珀酸衍生物的抗氧化活性

黄原胶寡糖与琥珀酸酐反应,得到3种衍生物XGOSSA-1、XGOSSA-2和XGOSSA-3,对产物进行FT-IR表征,GPC法测定其相对分子质量分别为7 560、6 400和7 430,3种衍生物的丙酮酸质量分数分别为4.6%、4.9%和4.9%,还原糖质量分数分别为20.5%、19.4%和19.0%,取代度分别为0.18、0.32和0.43。考察3种衍生物对超氧阴离子自由基、羟基自由基、DPPH自由基和过氧化氢的清除活性以及还原能力。3种衍生物的抗氧化强弱顺序为:XGOSSA-1XGOSSA-2XGOSSA-3。即当相对分子质量,还原糖和丙酮酸质量分数相近时,随着取代度的升高,抗氧化能力下降。造成这种现象的原因可能是随着取代度增大,活性羟基数目减少,导致抗氧化性能降低。     

橙皮苷衍生物的制备鉴定及抗氧化活性研究

目的:研究橙皮苷衍生物的制备、鉴定和抗氧化活性。方法:以天然橙皮苷为先导化合物,分别得到香叶木苷、香叶木素、7-O-乙氧羰亚甲基-香叶木素、7-O-羧亚甲基-香叶木素、橙皮素、3',7-O-二乙氧羰亚甲基-橙皮素、7-O-乙氧羰亚甲基-橙皮素、7-O-羧亚甲基-橙皮素共8个衍生物。比较测定了橙皮苷及其8个衍生物在同一浓度下的体外抗氧化活性,包括总抗氧化能力测定、清除自由基测定、对亚油酸自氧化和卵磷脂过氧化的抑制作用,并以橙皮苷和2,6-二叔丁基-4-甲基苯酚为对照,采用烘箱强化法测定了体外抗氧化活性较好的衍生物在不同浓度下对动物油和植物油过氧化值的影响。结果:8个衍生物的脂溶性或水溶性有所增强,在浓度为0.2 mg/mL时,橙皮苷及其8个衍生物均具有较好的体外抗氧化活性,其中化合物7-O-乙氧羰亚甲基-香叶木素对亚油酸自氧化和卵磷脂过氧化的抑制作用较强,分别为橙皮苷的2.15倍和1.92倍,它对猪油和大豆油的抗氧化效果均强于橙皮苷,并且抑制率随着浓度升高而增大,呈现出较好的量效关系,在0.2 mg/mL时,对猪油氧化的抑制率为52.17%,对大豆油氧化的抑制率为49.78%。结论:7-O-乙氧羰亚甲基-香叶木素脂溶性增强,具有比橙皮苷更强的抗氧化活性。     

阿魏酸衍生物对食用油脂抗氧化性能的研究

采用化学及生物催化的方法合成几种具有生理活性的阿魏酸衍生物。以过氧化值(POV)为指标研究不同阿魏酸衍生物对猪油及花生油的抗氧化性能。结果表明,阿魏酸衍生物对猪油和花生油都具有一定的抗氧化作用,在这些衍生物中阿魏酸双甘酯效果最好且存在剂量效应关系；添加了阿魏酸双甘酯的猪油和花生油在20℃条件下保存,其货架保存期分别可从114d延长至300d；81d延长至258d。     

低聚壳聚糖与葡萄糖和麦芽糖的美拉德反应及其衍生物的抗氧化性能

低聚壳聚糖(COS)作为氨基供体分别与提供羰基的葡萄糖和麦芽糖进行美拉德反应(氨基与羰基的物质量比均为3:1),考察了反应过程中吸光度和荧光值的变化。醇沉法提取低聚壳聚糖美拉德反应衍生物CG和CM。对两种衍生物进行红外表征和相对分子质量测定,并研究其对超氧阳离子O2.-、DPPH自由基的清除能力以及还原能力。结果显示:抗氧化能力强弱次序为CG>CM>COS,即美拉德反应后低聚壳聚糖衍生物抗氧化能力得到显著提高,且CG的抗氧化活性优于CM,表明与单糖进行美拉德反应制得的壳聚糖衍生物具有更好的抗氧化性。     

花生中白藜芦醇及其衍生物的研究进展

白藜芦醇及其衍生物作为重要的酚类化合物,由于具有抗菌、抗氧化、抗肿瘤等诸多的生物活性,近年来在食品、医药、植物生理等领域在国内外得到广泛深入的研究.简要介绍了花生中白藜芦醇及其衍生物的发现、组织分布、化学结构和生物活性;对近年来花生中白藜芦醇及其部分衍生物提取方法和常用的分析测定方法,如高效液相色谱法、高效气相色谱法、薄层色谱(TLC)法、荧光分光光谱法等应用情况进行了重点介绍,提出并总结了花生中白藜芦醇及其衍生物尚待研究的问题和应用前景.     

基于与α-丙氨酸/天冬酰胺美拉德反应的低聚壳聚糖衍生物的抗氧化性能研究

研究低聚壳聚糖(COS)与α-丙氨酸/天冬酰胺(低聚壳聚糖的羰基与氨基的物质量比均为4:1)的美拉德反应。醇沉法提取与α-丙氨酸/天冬酰胺反应8、16h以及24h的低聚壳聚糖衍生物,分别记为:CA-8、CA-16、CA-24、CN-8、CN-16以及CN-24。对衍生物进行红外表征,并研究其对超氧阳离子O2.-、DPPH自由基的清除能力以及还原能力。结果显示:美拉德反应后低聚壳聚糖衍生物抗氧化能力得到显著提高。抗氧化能力强弱次序为CA-8>CN-8、CA-16>CN-16、CA-24>CN-24,即随着反应时间增加,低聚壳聚糖与α-丙氨酸美拉德反应的衍生物抗氧化性始终更强,表明与小分子氨基酸进行美拉德反应制得的壳聚糖衍生物具有更好的抗氧化性。     

Antioxidative and antimicrobial effects of low molecular weight shrimp chitosan and its derivatives on seasoned-dried Pangasius fillets

This study was performed to evaluate the efficacy and applicability of low molecular weight shrimp chitosan (LMWC) and its derivatives (chitosan nanoparticles, CN; chitosan hydrochloride salt, CHS) as a preservative against lipid oxidation and microbial growth in seasoned-dried Pangasius hypophthalmus fillets during storage. All chitosans exhibited antioxidant activity in vitro (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, total reducing power ability and lipid peroxidation inhibition activity). The lipid oxidation in dried pangasius fillets that were seasoned by immersing in a solution containing 1.5% chitosan was suppressed during the 8-week storage; such effect was more effective than immersing in a solution containing 0.05% vitamin C. Likewise, LMWC and its derivatives were more effective in inhibiting microbial growth (lower total viable count and yeast/mould counts) than the control. These results clearly show that LMWC and its derivatives could be a potent antioxidant and antimicrobial preservative in seasoned-dried pangasius fillets during 8-week storage at 20 °C.     

壳聚糖及其衍生物在果酒中应用的研究进展

壳聚糖是一种天然、无毒的高分子聚合物,研究显示其在果酒酿造中具有抑菌、金属螯合、澄清和抗氧化等作用.但壳聚糖在酿酒过程中的上述活性强度及作用机理还未完全阐明.本文主要总结在果酒酿造中,壳聚糖及其衍生物的抗菌、抗氧化、澄清作用机理及应用现状,分析其目前存在的发展瓶颈问题,同时对潜在应用价值进行讨论,以期促进壳聚糖及其衍生...     

Synthesis of chitosan-caffeic acid derivatives and evaluation of their antioxidant activities

In this study, the antioxidant activities of different molecular weights (M_w) and grafting ratios of chitosan–caffeic acid derivatives were investigated. The grafting process was achieved using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC) as covalent connector under different conditions such as molecular-weight of chitosan, molar ratio of chitosan and caffeic acid, reaction temperature, pH, and reaction time. The half-inhibition concentrations (IC₅₀) of products were calculated by reduction of the 1,1-diphenyl picryl hydrazyl in the radical-scavenging assay and reduction of the Fe³⁺/ferricyanide complex to the ferrous form in reducing power assay. The EDAC showed maximum activity at 3-h, pH 5.0 and room temperature conditions, except high-molecular-weight chitosan in pH 2.0. The products were water-soluble in all pH and showed lower viscosity than native chitosan. The highest grafting ratio of caffeic acid was observed at 15% in low-molecular-weight chitosan. After 5% grafting of caffeic acid into chitosan, the grafting efficiency was increased by decreasing molecular-weight of chitosan at the same conditions. Caffeic acid has main role in the antioxidant activity of products. The maximum IC₅₀ of radical-scavenging activity (0.064 mg/ml) was observed at the highest caffeic acid containing derivative. Water-soluble chitosan and caffeic acid derivatives were obtained by this study without activity loss.     

基于美拉德反应的低聚壳聚糖衍生物的生物活性研究

以低聚壳聚糖作为氨基供体分别与提供羰基的葡萄糖和麦芽糖进行美拉德反应(氨基与羰基的物质量比均为1:1),醇沉法提取低聚壳聚糖美拉德反应衍生物CG和CM。对两种衍生物进行红外表征和分子量测定,并研究其抗氧化性能和抑菌性能。结果显示:两种衍生物均保留着低聚壳聚糖的特征吸收峰;其对O2.-、.OH及DPPH的清除能力以及还原能力和对大肠杆菌、铜绿假单胞菌和副溶血性弧菌的抑菌活性均得到显著提高,同时CG的抗氧化性和抑菌活性明显优于CM。即与单糖进行美拉德反应制得的壳聚糖衍生物具有更好的生物活性。     

Synthesis,characterization and functional properties of galactosylated derivatives of chitosan through amide formation

Low molecular weight chitosan (LMWC) and chitooligosaccharide (COS) derivatives were obtained by the introduction of lactobionic acid (LA) through amide formation, obtaining different complexes COS-LA and LMWC-LA (1–5), with a degree of substitution (DS) between 3 and 16%. The synthesis of these derivatives was monitored by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), High-Performance Liquid Chromatography-Size Exclusion Chromatography (HPLC-SEC) and proton Nuclear Magnetic Resonance (¹H NMR) analyses. Different functional properties, solubility, water binding capacity (WBC) and fat binding capacity (FBC), as well as the antioxidant activity (DPPH radical scavenging activity) of these derivatives were evaluated. Solubility, WBC and FBC increased in all of the chitosan derivatives respect to those of the native LMWC or COS. The most substituted derivative (LMWC-LA1, DS 15%) presented the highest value of solubility (14.4 mg/mL) while the highest levels of WBC and FBC were obtained for the derivative with a DS of 3% (LMWC-LA5; 4730% and 7100%, respectively). COS and COS-LA presented the best DPPH scavenging abilities, as shown by their low values of EC₅₀ (1.29 and 3.45 mg/mL, respectively). An inverse relationship between the DS of chitosan derivatives and antioxidant activity was observed. LMWC-LA5 (3% DS) was the derivative with the highest DPPH activity, being higher than LMWC in all the concentrations assayed (10.2–14.3% and 6.9–13.7%, respectively). Due to their enhanced functional properties, these chitosan derivatives could be considered as very promising for their future use as additives in the food industry (i.e. to bind fat and cholesterol or avoid hardening of foods).     

Antibacterial activity of N-alkylated disaccharide chitosan derivatives

Antibacterial activity of the water-soluble N-alkylated disaccharide chitosan derivatives against Escherichia coli and Staphylococcus aureus was investigated. It was found that the antibacterial activity of chitosan derivatives was affected by the degree of substitution (DS) with disaccharide and the kind of disaccharide present in the molecule. Regardless the kind of disaccharide linked to the chitosan molecule, a DS of 30-40%, in general, exhibited the most pronounced antibacterial activity against both test organisms. E. coli and S. aureus were most susceptible to cellobiose chitosan derivative DS 30-40% and maltose chitosan derivative DS 30-40%, respectively, among the various chitosan derivatives examined. Although the disaccharide chitosan derivatives showed less antibacterial activity than the native chitosan at pH 6.0, the derivatives exhibited a higher activity than native chitosan at pH 7.0. Antibacterial activity of the chitosan derivatives (DS 30-40%) against E. coli increased as the pH increased from 5.0 and reached a maximum around the pH of 7.0-7.5. The effect of pH on the antibacterial activity of chitosan derivatives against S. aureus was not as pronounced as that observed with E. coli. Population reduction of E. coli or S. aureus in nutrient broth increased markedly upon increasing the concentration of chitosan derivatives from 0 to 500 ppm. No marked increase in population reduction was noted with further increase in the concentration of chitosan derivatives even up to 2000 ppm.     

Effect of the molecular weight and concentration of chitosan in pork model burgers

Chitosan of high and low molecular weights was added at 0%, 0.25%, 0.5% and 1% concentrations to a burger model system. Burgers were evaluated by physicochemical analysis, cooking characteristic and storage stability. The antioxidant activity of chitosan was studied in vitro. The addition of chitosan influenced pH and color properties, in molecular weight and concentration dependent ways. Cooking properties were significantly affected by the chitosan. High molecular weight chitosan improved all cooking characteristics compared with control samples. Low molecular weight chitosan increased the shelf life of burgers, enhanced the red color and reduced total viable counts, compared with control and high molecular weight chitosan samples. The antioxidant activity of chitosan was dependent on molecular weight and concentration. The results indicate that high molecular weight chitosan (HMWC) improves all cooking characteristics and antioxidant activity while low molecular weight chitosan extends the red color and reduces total viable counts.