荞麦七提取物的体外抑菌活性研究

以铜绿假单胞菌、大肠杆菌、金黄色葡萄球菌及枯草芽孢杆菌为受试菌,通过最小抑菌浓度测定、抑菌圈的判断、生长曲线的绘制及菌液电导率的测定等方法,研究了荞麦七的4种提取物(水提物、蒽醌、鞣质、黄酮)的体外抑菌活性。结果表明:荞麦七水提物对枯草芽孢杆菌及铜绿假单胞菌抑制作用较强;荞麦七蒽醌对金黄色葡萄球菌及铜绿假单胞菌抑制作用较强;荞麦七鞣质对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌抑制作用较强;荞麦七黄酮对大肠杆菌抑制作用最强。     

5,6-O-苯乙烯基亚甲基-L-抗坏血酸的合成及其清除自由基和抗菌性能研究

在对甲苯磺酸为催化剂,N,N-二甲基乙酰胺为溶剂,环己烷为带水剂的体系中,肉桂醛与L-抗坏血酸加热回流得到标题化合物,产率41%.1HNMR的数据表明,产物为两个非对映异构体组成的混合物.用分光光度法研究了产物清除羟基自由基、超氧阴离子自由基和DPPH自由基的能力.结果表明,当受试物的物质的量浓度相同时,产物清除上述3种自由基的能力与L-抗坏血酸基本相当,略比TBHQ强.用MTT法测试了产物对大肠杆菌、枯草芽孢杆菌和铜绿假单胞菌的抗菌作用.结果表明,产物的抑菌活性相当于或略高于肉桂醛,比L-抗坏血酸更强.     

苯佐卡因缩芳醛席夫碱的合成及其抑菌活性

以苯佐卡因和芳醛为原料合成了3种标题化合物,用IR、1HNMR和元素分析对产物的结构进行了确证。采用滤纸片法测试了3种标题化合物对大肠杆菌、金黄色葡萄球菌及铜绿假单胞菌的抑菌性能。实验结果表明,标题化合物对所试3种细菌均有一定的抑菌活性能。其中,苯佐卡因缩水杨醛席夫碱对铜绿假单胞菌的抑菌效果最好,其抑菌圈直径达16.8 mm。     

反-β-正烷氧羰基丙烯酸-6-D-异抗坏血酸酯的合成和性能研究

反-β-正烷氧羰基丙烯酸与SOCl2反应得到反-β-正烷氧羰基丙烯酰氯,后者再与D-异抗坏血酸反应,得到标题化合物。其结构经IR、1HNMR、13CNMR和MS确证。用分光光度法测试了反-β-正己氧羰基丙烯酸-6-D-异抗坏血酸酯清除DPPH自由基的活性,用孔穴扩散法测试了标题化合物的抗菌活性。结果表明,在物质的量浓度相等时,D-异抗坏血酸与反-β-正己氧羰基丙烯酸-6-D-异抗坏血酸酯对DPPH自由基的清除率基本接近;在给药量为2 mg/mL时,标题化合物对金黄葡萄球菌、大肠杆菌、枯草芽孢杆菌的抑菌圈直径在5.00~7.25 mm之间,对细黄链霉菌的抑菌圈直径在15.00~17.50 mm之间。     

川葵精油的制备及杀菌性能研究

以同时蒸馏法提取川葵精油,经GC-MS分析检测得川葵挥发精油的主要成分为异硫氰酸酯类(ITCs);采用滤纸片法和肉汤稀释法研究其抑菌作用,结果表明,川葵精油对金黄色葡萄球菌、白色葡萄球菌、枯草芽孢杆菌、铜绿假单胞杆菌、沙门氏菌、宋内志贺氏菌、大肠杆菌、青霉菌表现出有不同强度的抑制作用,对8种供试菌的最小抑菌浓度为64～256 mg/mL,川葵精油具有一定的杀菌效果。     

恶臭假单胞菌降解光氧化褐煤工艺条件优化

从6种细菌(铜绿假单胞菌、黄杆菌、枯草芽孢杆菌、多粘类芽孢杆菌、恶臭假单胞菌和金色葡萄球菌)中筛选出降解光氧化褐煤的优势菌株恶臭假单胞菌,并通过单因素实验优化了恶臭假单胞菌降解光氧化内蒙古胜利褐煤的工艺条件。确定恶臭假单胞菌降解光氧化内蒙古胜利褐煤的最佳工艺条件为:煤加量0.3 g·(20 mL)~(-1)、接种量2.0 mL·(20 mL)~(-1)、培养箱振荡频率160 r·min~(-1)、降解时间12 d、煤样粒度(-0.15+0.075) mm、降解温度30℃。     

槲皮素抗菌活性的研究

以大肠杆菌、金黄色葡萄球菌等为实验菌株,采用药敏纸片法考察槲皮素的抗菌活性.槲皮素对金黄色葡萄球菌的抗菌效果最好,最低杀菌浓度小于0.0061 μmol·mL-1;对胶质芽孢杆菌抗菌效果次之,最低抑菌浓度小于0.0061 μmol·mL-1;对大肠杆菌、苏云金芽孢杆菌、枯草芽孢杆菌、铜绿假单胞菌也有较为明显的抗菌效果,最低抑菌浓度分别为0.0242 μmol·mL-1、0.0061 μmol·mL-1、0.0485 μmol·mL-1、0.0121 μmol·mL-1,最低杀菌浓度分别为1.5522 μmol·mL-1、6.2086 μmol·mL-1、3.1043 μmol·mL-1、1.5522 μmol·mL-1;对人仓白杆菌无抗菌效果.槲皮素具有广谱抗菌性,并且对革兰氏阴性菌的抗菌作用强于革兰氏阳性菌.     

壳聚糖对尿路感染主要病原菌的体外抑制作用

为研究壳聚糖对尿路感染主要病原菌的抑制效果,采用纸片扩散法测定壳聚糖对大肠杆菌、金黄色葡萄球菌、肺炎克雷伯杆菌、铜绿假单胞菌的抑菌活性,固体平板培养基稀释法确定最小抑菌浓度,比浊法测定细菌的生长曲线并计算壳聚糖对细菌生长的抑制率。结果表明,壳聚糖对大肠杆菌、金黄色葡萄球菌、肺炎克雷伯杆菌、铜绿假单胞菌均具有抑制作用,且抑制作用与其浓度呈正比,最小抑菌浓度为0.05%,抑制效果依次为:金黄色葡萄球菌≥肺炎克雷伯菌大肠杆菌≥铜绿假单胞菌,还能延长4种菌生长的调整期,并使它们在对数期出现之前就已基本停滞生长。     

海洋细菌的抑菌谱研究及鉴定

本实验采用琼脂扩散法研究了11种来源于北冰洋沉积物的海洋细菌对9种人类和动物致病菌(大肠杆菌,金黄色葡萄球菌,白色念珠菌,弧菌,铜绿假单胞菌,沙门氏菌,肺炎克雷伯菌,屎肠球菌,鲍曼不动杆菌)的抑菌谱。并对效果最好的65号菌株进行了鉴定,确定其为芽孢杆菌。     

铜绿假单胞菌与秀丽隐杆线虫互作研究进展

铜绿假单胞菌（Pseudomonas aeruginosa）属于革兰氏阴性杆菌,对人和动物具有潜在致病性。秀丽隐杆线虫（Caenorhabditis elegans）是一种以大肠杆菌为食的微小模式生物。铜绿假单胞菌与秀丽隐杆线虫互作模型常用于研究铜绿假单胞菌对宿主损害机制及宿主应对铜绿假单胞菌侵染的策略。本文从铜绿假单胞菌对秀丽隐杆线虫侵染和宿主应对策略这两个角度进行综述,以期为研究铜绿假单胞菌致病机制及筛选治疗其引发疾病的治疗思路提供参考。     

A sensitive test to evaluate antioxidants in oils and fatty esters

Efficacy of common lipid antioxidants was evaluated by use of sesamol dimer and hemoglobin (SD method), and the method was compared with traditional peroxide value (POV) method. There were good correlations between the increases in SD and POV values, with different substrate oils and with the different antioxidants. While the POV method requires 500 mg of the substrate oil, the SD method requires less than 10 mg of the oil. The SD method is useful to estimate the potency of antioxidants with a small amount of oils and fatty esters.     

Analysis of triacylglyceride hydroperoxides in vegetable oils by nonaqueous reversed-phase high-performance liquid chromatography with ultraviolet detection

Triacylglyceride hydroperoxides (HPO-TAG), the primary autoxidation products of triacylglycerides (TAG), have been analyzed in polyunsaturated vegetable oils by means of nonaqueous reversed-phase high-performance liquid chromatography (HPLC) with ultraviolet detection. Using a retention time model based on equivalent carbon numbers, mono- and bishydroperoxy TAG and hydroxy TAG could be identified. The correlation between the peroxide value (POV) determined by iodometric titration and quantitative HPLC results for HPO-TAG was established for sunflower oil samples with POV between 0.5 and 50 meq/kg. The recovery of HPO-TAG in the HPLC procedure was found to be close to 100% in the POV range of 4 to 71 meq/kg. Absolute quantitative results for HPO-TAG in sunflower oil samples could not be obtained accurately, as molar extinction coefficients of HPO-TAG occurring in natural oils deviate from those of available HPO-TAG reference compounds.     

Effect of roasting on oxidative and tocopherol stability of walnut oil during storage in the dark

The effect of roasting on the oxidative stability of oil from walnut (Juglans sinensis Dode) was investigated by observing changes in the characteristics of oils from unroasted and roasted kernels during storage in the dark at 60°C. Walnut kernels were roasted at 160°C for 15 min prior to oil extraction with the solvent, hexane. Roasting of kernels increased the peroxide value (POV) and conjugated dienoic acid (CDA) value of the oil. The rate of increase in the POV was significantly lower in roasted than in the unroasted walnut oil during storage at 60°C (1.90 vs. 1.06 and 4.45 vs. 3.55 meq/kg/day during induction period (IP) and post‐IP, respectively). Roasting of kernels significantly increased the IP of walnut oil from 0.89 to 3.39 days during storage. The total tocopherol content in roasted walnut oil was lower as compared to that in unroasted one (277.77 vs. 314.88 µg/g). However, the rate of degradation of total tocopherol during storage was lower in roasted walnut oil compared to unroasted one (1.18 vs. 2.17%/day), which showed that the tocopherol retention was higher in roasted walnut oil. These results indicate that roasting of kernels increased the oxidative and tocopherol stability of oil during storage in the dark.     

Effects of Phosphatidylcholine on Interaction of α-Tocopherol and β-Carotene in Photosensitized Oxidation of Emulsions

The interaction between α‐tocopherol (500 mg/kg) and β‐carotene (10 mg/kg) during chlorophyll‐photosensitized oxidation of a sunflower oil emulsion was studied in the presence or absence of phosphatidylcholine (PC, 250 mg/kg) by determining peroxide (POV) and conjugated dienoic acid (CDA) values. Chlorophyll, α‐tocopherol, β‐carotene, and PC contents in the emulsion were also monitored. α‐Tocopherol and β‐carotene individually and interactively decreased the POV and CDA values of oil in the emulsion by singlet oxygen quenching. PC decreased the POV and CDA values of oil, however, the values of the emulsion with added α‐tocopherol, β‐carotene, and PC were not significantly different from those of the emulsion with added α‐tocopherol and β‐carotene without PC. Contents of α‐tocopherol did not change during 24‐h oxidation, whereas co‐present PC significantly caused α‐tocopherol and chlorophyll degradation. β‐Carotene and PC contents significantly decreased to 45.5 and 51.3 %, respectively, after 24 h, and α‐tocopherol protected β‐carotene from degradation. The results suggest that PC had no net effects on the interactive antioxidant activity of α‐tocopherol and β‐carotene during chlorophyll‐photosensitized oxidation of the emulsion through free radical generation, chlorophyll degradation, and lessening the potency of α‐tocopherol as a singlet oxygen quencher.     

马铃薯皮中多酚类物质的抗氧化性研究

通过体外抗氧化体系测定马铃薯皮多酚的抗氧化活性。除超氧阴离子的能力;马铃薯皮多酚清除羟基自由基的能力;马铃薯皮多酚清除DPPH自由基的能力;马铃薯皮多酚对油脂的抗氧化能力。马铃薯皮多酚对超氧阴离子的清除率最高达18.33%,且在低浓度清除能力明显高于同浓度抗坏血酸(Vc);马铃薯皮多酚对羟基自由基的清除率最高达92.26%。对DPPH自由基清除率最高达86.08%。油脂中添加马铃薯皮多酚提取液,可以明显降低油脂的过氧化值(POV)。马铃薯皮多酚对超氧阴离子,羟基自由基和DPPH自由基都有很好的清除效果,且在一定程度上降低油脂过氧化值随时间而延长的程度,是很好的天然抗氧化剂。     

1,2,6-三磷酸-3,4,5-三己酸肌醇酯的制备及其抗油脂氧化活性研究

植酸水解得到1,2,6-三磷酸肌醇,然后与三乙胺反应生成相应的铵盐,在脂酶NovozyTne 435催化下,该铵盐与己酸反应生成1,2,6-三磷酸-3,4,5-三己酸肌醇酯.以过氧化值(POV)和茴香胺值(AV)为指标研究不同剂量的1,2,6-三磷酸-3,4,5-三己酸肌醇酯对策籽油的抗氧化性能.结果表明,1,2,6-三磷酸-3,4,5-三己酸肌醇酯对菜籽油具有明显的抗氧化作用且存在剂量效应关系,在添加量为0.06%时,其抗氧化能力和0.02%BHT相当.     

Effect of water content on volatile compounds derived from soybean oils in cans

Soybean oil-water cans with different soybean oil/water ratios were prepared and stored. The volatiles and POV values of these samples were monitored. Water in cans caused the production of larger amounts of volatiles just after sterilization, however, during the storage period, cans without water had a higher rate of production of volatile compounds. It was postulated that POV values do not reflect the changes of volatile compounds in cans.     

Thermal Stability of Rapeseed Oil Fortified with Unsaturated Fatty Acid Sterol Esters

The thermal stability of rapeseed oil fortified with 3 % sterol linolenate, sterol linoleate, and sterol oleate was investigated using the Rancimat accelerated oxidation method. The results indicated that the sterol ester content in fortified oil displayed positive correlations (P < 0.05) with total phenols and tocopherols and significant negative correlations (P < 0.05) with acid value (AV), peroxide value (POV), conjugated diene value, \(\varDelta E\) value, viscosity, and polyphenols and γ-tocopherol levels. The sterol ester content in fortified oil was found to significantly decrease when the oil was heated at 110 °C. The rate of increase of the AV, POV, \(\varDelta E\) value, and viscosity, and the rate of decrease of polyunsaturated fatty acid, tocopherol, and polyphenol contents were accelerated with the increase of the degree of unsaturation of fatty acid sterol esters in rapeseed oil during heating. Therefore, the oxidative stability is further reduced by increasing the degree of unsaturation, as the instability of fortified oil is mainly due to the decomposition of unsaturated fatty acid sterol esters. The addition of lipid-soluble polyphenols is an effective method to improve the stability of rapeseed oil fortified with unsaturated fatty acid sterol esters.     

2,2’-亚甲基双(4-甲基-6-α-甲基苄基苯酚)的合成与性能评价

以单苯乙烯化对甲酚(单酚)为底物,与35%~37%的甲醛水溶液在酸催化的条件下进行反应,合成了一种酚羟基邻位取代具有活泼α-H原子的双酚类抗氧剂2,2’-亚甲基双(4-甲基-6-α-甲基苄基苯酚)。最佳工艺条件:n(单酚)∶n(甲醛)=1∶3,80℃回流反应5 h,产率85%。测定加抗氧剂的润滑油油样的过氧化值(POV)表明,合成双酚抗氧剂具有比抗氧剂2246更好的抗氧性。     

环己酮异VC缩酮的合成及其抗氧化性能研究

以对甲苯磺酸为催化剂,N,N-二甲基乙酰胺(DMAc)为溶剂,环己烷为带水剂,由环己酮与异VC反应合成环己酮异VC缩酮。用正交实验获得了较优的合成条件:环己酮0.9814 g(10mmol),异VC 2.8179 g(16 mmol),对甲苯磺酸0.3804 g(2 mmol),DMAc 8 mL,环己烷9 mL,反应温度120~125°C,反应时间2.5 h,标题化合物的收率为84.82%。用1H NMR,FT IR和EI-MS确定了标题化合物的结构。参照我国规定的食品抗氧化剂最高允许浓度,将异VC、没食子酸丙酯(PG)、环己酮异VC缩酮和叔丁基对苯二酚(TBHQ)分别应用于新鲜茶籽油中进行抗氧化试验,结果表明,环己酮异VC缩酮是一种良好的油溶性抗氧化剂。例如,当异VC、PG、环己酮异VC缩酮和TBHQ添加量分别为茶籽油质量的0.02%、0.01%、0.029%和0.02%时,60°C下抗氧化试验8天后,油样的过氧化值(POV)分别为27.60、24.97、8.10和9.01 meq/kg。