中国主要水果抑制肝癌HepG2细胞和结肠腺癌Caco-2细胞增殖活性评价

分别采用Folin-Ciocalteu法测定了水果提取物的总酚含量,采用亚甲基蓝法测定了其抗人肝癌细胞Hep G2和人结肠腺癌细胞Caco-2增殖的活性,分析了总酚含量与抗Hep G2和Caco-2细胞增殖活性之间的相关性。结果显示,25种水果中李子的总酚含量最高(1686.08±96.94μmol GAE/100鲜果),西瓜(83.54±2.10μmol GAE/100 g鲜果)和哈密瓜(79.35±0.76μmol GAE/100 g鲜果)的总酚含量最低;在可测出抗增殖EC50值的水果中,李子(18.99±0.06 mg/m L)和番石榴(20.94±0.09 mg/m L)抗Hep G2细胞增殖的活性最强,梨的活性最弱(389.63±10.82 mg/m L)。李子抗Caco-2细胞增殖的活性最强(8.73±0.11 mg/m L),火龙果的活性最弱(388.07±7.04 mg/m L)。水果的抗Hep G2和Caco-2细胞增殖活性与其总酚含量相关性显著(R2=0.4147,p0.01;R2=0.4071,p0.05),该相关性表明水果中的多酚具有良好的抗肿瘤细胞增值的活性。     

36种蔬菜抑制肝癌HepG2和结肠腺癌Caco-2细胞增殖活性评价

为明确36种中国主要消费蔬菜多酚提取物的总酚含量和抑制人肝癌细胞Hep G2和人结肠腺癌细胞Caco-2增殖活性,分别采用Folin-Ciocalteu法确定了蔬菜提取物的总酚含量,采用亚甲基蓝法确定了其抗Hep G2和Caco-2细胞增殖的活性,分析了总酚含量与抗Hep G2和Caco-2细胞增殖活性之间的相关性。结果表明,36种蔬菜每百克中没食子酸当量:芥蓝(973.09±31.29)μmol/hg,莲藕(920.55±29.00)μmol/hg,它们的总酚含量最高;丝瓜(44.94±4.16)μmol/hg,其总酚含量最低。在可测出抗增殖EC50值的蔬菜中,韭菜(15.96±0.88)mg/m L和蒜苔(17.54±0.03)mg/m L,它们的抗Hep G2细胞增殖的活性最强;上海青(390.52±17.63)mg/m L和空心菜(394.25±11.89)mg/m L,它们的活性最弱。韭菜抗Caco-2细胞增殖的活性最强,为(21.08±1.67)mg/m L;青尖椒的活性最弱,为(390.17±4.78)mg/m L。这些蔬菜的抗Hep G2和Caco-2细胞增殖活性与其总酚含量相关性均不显著(R2=0.027 1,p0.05;R2=0.151 3,p0.05),表明蔬菜的抗肿瘤活性不能单从其多酚含量的高低来推测。     

脱脂米糠碱溶醇溶物抗氧化活性研究

脱脂米糠的碱溶醇溶物具有良好的体外抗氧化活性。从脱脂米糠中提取抗氧化物,采用羟基自由基体系、DPPH自由基体系、超氧阴离子自由基体系、亚油酸体系、纯猪油体系、ORAC体系、PC12细胞氧化损伤体系,研究脱脂米糠的碱溶醇溶物清除自由基和脂质过氧化物的效果。结果表明:当样品质量浓度为0.2 g/m L时,其对·OH的清除率超过50%;样品质量浓度为0.6mg/m L时,酶解产物的DPPH清除率可达90%;样品质量浓度45.0 mg/m L时,O_2-清除率约为50%;样品浓度高于60μg/m L时,样品的ORAC值与异VC钠相当;在亚油酸体系中,500μg/m L的样品有明显的抗氧化效果,500μg/m L和1 mg/m L的样品显著好于相同浓度的异VC钠;在猪油抗氧化体系中,质量分数5%样品添加组的猪油达到相同的pov所需的天数延长;随着样品质量浓度的增加,PC12细胞存活率呈现依次升高的趋势,5 mg/m L的样品的PC12细胞存活率达到82.2%,抗氧化效果好于200μmol/L的Trolox。     

不同多糖配伍对H2O2诱导的皮肤细胞老化的抑制作用

本研究为明确混合多糖配伍使用抑制皮肤细胞衰老的作用是否优于单一多糖,通过利用不同浓度的H_2O_2诱导人皮肤成纤维细胞(HSF)、人角质形成细胞(Ha Ca T)出现损伤老化,在此基础上,采用MTT法和生化试剂盒检测,分别检测细胞的存活率及超氧化物歧化酶(SOD)、丙二醛(MDA)、羟脯氨酸(HYP)的含量。本实验所建立的Ha Ca T及HSF细胞过氧化模型的存活率分别约为72.00%和65.00%,研究发现四种单一多糖组对两种细胞老化模型的存活率与模型组相比差异没有统计学意义(p0.05);其中SOD、MDA、HYP的含量与模型组相比,除个别指标外,差异没有统计学意义(p0.05)。在Ha Ca T细胞老化模型中,混合多糖组的存活率在74.93%～80.43%之间,SOD含量在6.99 U/mg～7.56 U/mg之间,MDA含量在7.44μmol/g～8.41μmol/g之间,HYP含量表达在2.30μmol/g～2.43μmol/g之间;在HSF细胞老化模型中,混合多糖组的存活率在76.23%～78.14%之间,SOD含量在6.30 U/mg～8.90U/mg之间,MDA含量在7.03μmol/g～8.93μmol/g之间,HYP含量在2.19μmol/g～2.53μmol/g之间;以上指标与模型组相比差异均有统计学意义(p0.01或p0.05)。因此,混合多糖组的整体改善效果更为显著,它能够提高衰老表皮细胞生存率,提高模型细胞SOD、HYP含量,使MDA含量降低。研究提示我们在对抗H_2O_2诱导的HSF、Ha Ca T细胞氧化衰老实验中,在相同干预浓度下,不同多糖配伍后的混合多糖比组分单一多糖单独使用效果显著。     

余甘子总多酚的提取及其抗氧化活性研究

采用溶剂浸提法提取余甘子多酚,并研究其抗氧化活性。通过福林酚法测定多酚的含量,以提取液中总多酚含量为指标,采用单因素实验确定对多酚提取影响较大的3个因素(浸提时间、浸提温度、乙醇浓度),进一步通过正交试验优化提取方案;通过体外实验,对余甘子多酚在清除DPPH自由基、羟基自由基和抑制自发性肝脂质氧化方面的作用进行研究。结果表明,没食子酸在1～5 mg/m L范围内线性关系良好,线性回归方程为:y=0.1431x+0.0791(r=0.9997);余甘子多酚最佳提取方案为:提取时间135 min,浸提温度70℃,乙醇浓度45%,此条件下的总多酚含量为(0.2427±0.008) mg GAE/mg;余甘子多酚总还原能力在0.2～1 mg/m L范围内稍低于茶多酚,但DPPH自由基清除率、羟自由基清除率、自发性肝脂质氧化抑制率均明显高于茶多酚,其中清除DPPH自由基的EC_(50)为(9±0.01)μg/m L,清除羟自由基的EC_(50)为(0.47±0.01) mg/m L,抑制自发性肝脂质氧化的EC_(50)为(122±2)μg/m L。余甘子多酚具有较好的抗氧化活性,有较好的应用前景。     

猪血球胃蛋白酶水解物抗氧化活性的研究

以脂质氧化抑制力(LA)、亚铁离子螯合能力(FICP)、二苯代苦味酰肼(DPPH)自由基清除能力(DRSA)为测定指标,探讨了猪血球胃蛋白酶水解物(PDPH)的抗氧化活性。结果表明,PDPH具有极好的亚油酸脂质氧化抑制力(P<0.01)、一定的FICP(P<0.05)和DRSA(P<0.05)。PDPH的脂质氧化抑制力在10μg/mL时为α-生育酚的4.38倍,100μg/mL时为5.50倍;金属离子螯合能力在100μg/mL样品浓度,50μmol/L FeCl2时的螯合率约为10μmol/L EDTA的1.23倍;在10-100μg/m L样品浓度时基本无DRSA,但在500μg/m L的DR-SA为53.8%。     

基于HepG2细胞模型的褐赭色羊肚菌多酚抗氧化及抗增殖活性研究

本实验研究了褐赭色羊肚菌游离酚和结合酚体内抗氧化能力以及对HepG2细胞的毒性和抗增殖作用。采用HPLC对褐赭色羊肚菌多酚组分进行鉴定,测定多酚抗氧化能力指数(ORAC);以人肝癌细胞HepG2为模型,测定多酚细胞抗氧化活性(CAA值)及抗增殖活性(EC50值)。结果显示:褐赭色羊肚菌游离酚和结合酚含量分别为(4.27±0.07)、(0.14±0.01)mg GAE/g DW;其ORAC值分别为(4624.52±400)、(429.41±60)μmol TE/100 g DW;CAA值分别为(15.33±0.60)、(0.37±0.01)μmol QE/100 g DW(PBS清洗)和(51.84±0.83)、(1.27±0.04)μmol QE/100 g DW(不经PBS清洗)。游离酚和结合酚浓度为125μg/m L和70μg/m L时,对HepG2细胞增殖抑制率分别为77.28%、66.31%,且试验浓度范围内,羊肚菌多酚对HepG2基本无细胞毒性。褐赭色羊肚菌多酚具有一定的细胞抗氧化及抗增殖活性,可将褐赭色羊肚菌作为开发此类功能营养食品的原料,为羊肚菌的进一步综合利用提供理论依据。     

皱纹盘鲍内脏脂质对人肝癌细胞HepG2脂质调节作用研究

本研究探讨了皱纹盘鲍(Haliotis discus hannai)内脏脂质(Haliotis discus hannai visceral lipid,HDHL)对人肝癌细胞HepG2的脂质代谢的影响,对HDHL脂肪酸成分、HepG2细胞活性、细胞内胆固醇和甘油三酯含量以及脂肪酸代谢相关m RNA基因的表达情况进行了研究。研究发现HDHL中不饱和脂肪酸占总脂肪酸含量59.50%,其中多不饱和脂肪酸占29.71%。HDHL与HepG2细胞共孵培养24 h及48 h后,浓度为0～240μg/m L的HDHL对HepG2细胞无毒性影响。30～240μg/m L HDHL可显著降低HepG2总胆固醇含量,30～120μg/m LHDHL共孵HepG2细胞后,细胞内甘油三酯含量显著降低。q PCR结果显示HDHL可显著降低HepG2细胞脂肪酸合成相关基因SREBP1c、ACC1、FAS和脂肪酸转运吸收相关基因CD36 m RNA水平的表达,提高线粒体脂肪酸氧化基因CPT1的表达。因此,HDHL可能通过抑制脂肪酸合成和脂肪酸转运,增强线粒体中脂肪酸氧化等途径有效调节细胞脂质代谢,该研究为脂质调节功能食品的开发提供理论依据。     

高效液相色谱-蒸发光散射法分析海参脑苷脂和神经酰胺的含量

目的建立了一种高效液相色谱-蒸发光散射检测方法(high performance liquid chromatography coupled with evaporative light-scattering detection,HPLC-ELSD)同时分析海参中脑苷脂和神经酰胺含量的方法。方法以TSKgel CN-80Ts柱为分离柱,正己烷-异丙醇-二氯甲烷-甲醇为流动相,采用梯度洗脱方式,流速1.0m L/min,漂移管温度50℃,氮气流速2.4 L/min。结果在优化条件下,18 min内完成分离,脑苷脂的线性范围为2.5~250μg/m L,检出限为0.5μg/m L(S/N=3),相关系数R0.99,神经酰胺的线性范围为5~150μg/m L,检出限为0.05μg/m L(S/N=3),相关系数R0.99,方法稳定性良好;不同种海参中脑苷脂和神经酰胺含量存在较为明显的差异,含量范围分别为0~4.44 mg/g和0.24~2.21 mg/g。其中,猪参的脑苷脂含量最高为4.44 mg/g,而白底靴参的脑苷脂未能检出。阿拉斯加红参的神经酰胺含量最高为2.21 mg/g,而海地瓜神经酰胺含量最少。结论所建立的方法灵敏、准确、快速,可应用于食品中脑苷脂和神经酰胺的同时定量分析。     

高粱不同溶剂提取物的抗氧化活性及抗细胞氧化应激作用

以红高粱为原料,采用测定清除DPPH·和ABTS~+·能力、总抗氧化能力3种方法比较了不同提取溶剂提取物的抗氧化活性,测定了总酚含量,并分析了总酚含量与抗氧化方法的相关性。并研究了高粱多酚对细胞氧化应激的影响。结果表明,60%乙醇提取物中总酚含量最高,达到315.45 mg GAE/100 g DW。DPPH·清除能力达到89.88%,ABTS~+·清除能力达到89.9%,总抗氧化能力为15.93 mmol TEAC/100 g DW,其中ABTS~+·与总酚的相关系数最高,为0.80(P=0.1930.05),但是不显著。高粱多酚质量浓度为2 mg/m L时,对H_2O_2诱导小鼠肝细胞产生MDA抑制率最高,为72.96%。在质量浓度为300μg/m L时,使得PC12细胞的存活率达到94.11%。由此可见,红高粱具有很强的体外抗氧化能力,并对细胞的氧化应激具有保护作用。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.