番木瓜籽中异硫氰酸苄酯抗癌抑菌功能研究进展

番木瓜(Carica Papaya)是一种极具营养价值而被广泛种植的热带水果,其籽中含有苄基硫代葡萄糖苷(Glucosinolate,GS),约占番木瓜重量7%,是果肉加工的废弃物。GS主要存在于细胞空泡,当其接触到芥子酶就会被水解,生成异硫氰酸酯类(Isothiocyanates,ITCs)。ITCs是十字花科植物的次生代谢产物,是一类重要的有机合成中间体,公认具有防癌抗癌功效以及抑菌作用,异硫氰酸苄酯(Benzyl isothiocyanate,BITC)是ITCs中生物学效果最为明显的一种。BITC对许多癌症有明显的抑制作用,可以阻断癌细胞增殖分化;BITC对致病菌有抑制甚至杀死作用,这种抑菌活性可以作用于细菌和霉菌。本文结合国内外相关研究现状,综述BITC在防癌抗癌及抑菌方面的研究进展,为番木瓜籽副产物BITC更深一步的加工以及番木瓜综合利用率的提升提供一定的理论依据。     

葡萄及葡萄酒生理活性物质的研究概况(Ⅲ)--预防癌症、炎症、神经疾患及其它疾病效果

综述了葡萄来源的多酚类化合物(GPE)在预防癌症、炎症、神经疾患以及其它疾病方面所取得的研究进展。大量研究表明葡萄来源的原花色素以及白藜芦醇类物质具有预防胃癌、乳腺癌、口腔癌、肝癌、前：立腺癌、结肠癌以及白血病等的潜力。它们的抗癌作用机制主要有六个方面：(1)调节相Ⅰ细胞色素以及相Ⅱ脱毒酶；(2)免疫调节效果；(3)抑制环状氧合酶(COX)和蛋白酶激酶的活性；(4)诱导肿瘤细胞凋亡以及分化；(5)类雕激素效果；(6)抑制核(糖核)苷酸还原酶活性。另外，葡萄多酚类化合物还显出较好的预防炎症、神经疾患、糖尿症以及白丙障等效果，此类活性大多与它们对活性氧的清除活性密切相关。     

清炒方式对西兰花异硫氰酸酯含量及活性的影响

西兰花含有硫代葡萄糖苷,经过内源性黑芥子酶酶解可得到有多种生物活性的异硫氰酸酯(isothiocyanates,ITCs)。但是西兰花烹饪过程中黑芥子酶易失活,导致ITCs含量降低。该文研究新鲜西兰花(raw broccoli,RB)、直接炒西兰花(direct stir-fried broccoli,DS)、酶解后再炒的西兰花(hydrolyzed and stir-fried broccoli,HS)中各ITCs含量的差异,并以小鼠黑色素瘤B16细胞为对象,研究RB、DS、HS组西兰花提取物对小鼠黑色素瘤B16细胞抑制作用,以及对B16细胞醌氧化还原酶(quinone oxidoreductase,NQO1)活性的诱导作用。结果表明,RB组提取物中总ITCs含量最高,为(36.22±12.01)mg/100 mg;DS和HS组中ITCs含量分别为(10.64±2.41)mg/100 mg和(30.90±10.88)mg/100 mg,RB组与HS组提取物的含量相比无显著差异(P0.05),DS组提取物的含量最低。各组西兰花提取物对B16细胞的抑制作用无显著差异(P0.05);对照组、RB、DS、HS组提取物作用B16细胞后,细胞中NQO1的活性分别为(4.22±1.60)、(19.53±3.59)、(12.58±4.32)、(22.57±3.56)(nmol还原MTT/min/mg蛋白),RB和HS组提取物能显著提高NQO1的活性,与DS组存在显著性的差异(P0.05)。由此可知,经过酶解后再炒的西兰花ITCs含量和活性与新鲜西兰花相比无显著性差异,该烹饪方法能有效维持西兰花的功能成分和营养价值。     

切分、汽蒸及脱水对甘蓝叶片中硫苷-黑芥子酶系统的影响

以结球甘蓝(Brassica oleracea var.capitata L.)为材料,研究切分、汽蒸及脱水对甘蓝叶片中硫苷(glucosinolates,GLs)和异硫氰酸盐(isothiocyanate,ITCs)含量、黑芥子酶(myrosinase,MYR)活性的影响。结果表明:切分度为1.00 cm2时,总GLs、脂肪族GLs含量最低,ITCs含量最高,比新鲜原料提高38.91%;随汽蒸时间的延长,MYR活性降低,汽蒸时间为60 s时,ITCs含量最高,比新鲜原料提高53.70%,此时总GLs、脂肪族GLs含量最低;添加葡萄糖质量分数为5%时,ITCs含量最高,比新鲜甘蓝提高76.26%;热风干燥温度为50℃时,ITCs含量比新鲜原料高89.88%,总GLs、脂肪族GLs含量最低。获得合适的条件为:切分大小1.00 cm~2,汽蒸60 s,添加质量分数5%的葡萄糖,50℃热风干燥。     

谈谈癌症患者局口问题

癌症患者的忌口有两种含义：与肿瘤发病有关的食物，容易被黄曲霉素污染的食物、易霉变的食物、含有致癌物的食品、易被致癌物如苯并芘污染的食物等，当然不能吃，这是忌口的一般含义。通常人们所关心的是另一种含义的忌口，就是对于癌症患者的治疗康复，究竟哪些食品不能吃，担心吃了会引起肿瘤的复发或转移。     

槲皮素——有益于健康的天然化合物

槲皮素属于生物黄酮类,广泛分布于人们的食用植物中。槲皮素具有多方面的生物活性。槲皮素作为一个对人们健康非常有益的天然化合物,近几年来引起了国内外研究者的广泛的兴趣,研究论文呈直线上升趋势。自由基可导致细胞损伤,是产生许多疾病的主要原因。槲皮素主要的功能是抗氧化,清除自由基。槲皮素能使血管舒张作用,改善内皮细胞、加强氧化应激;抑制低密度脂蛋白氧化;减少粘附分子和其他炎症标记物;防止神经元氧化和炎性损伤血管内皮功能。槲皮素还可通过清除超氧阴离子、羟自由基及与自由基相关酶作用对抗氧化应激过程,从而保护心肌细胞。大量的证据表明,多食用含有槲皮素的水果和蔬菜可减少心血管疾病。槲皮素可以阻止潜在的致癌物成为最终的致癌物。研究表明槲皮素能有效地阻止环境中致癌物在人体内的活化;能加快致癌物在人体内的降解,并促进其排出;能诱导肿瘤细胞的分化,促进肿瘤细胞的凋亡。槲皮素对癌症防治具有重要作用。     

异硫氰酸酯分析方法研究进展

异硫氰酸酯（ITCs）是一类通式为R-N=C=S的有机化合物。它们是十字花科某些蔬菜的独特风味成分,具有多种生理活性。重点对ITCs定性、定量分析方法的最新研究进展进行了系统的分析和介绍。     

合理膳食、均衡搭配,加工肉制品并非不可吃

正10月26日,世界卫生组织正式发布消息,其下属国际癌症研究中心(IARC)将加工肉制品列入致癌食物名单——"一类致癌物",而且红肉本身也属于可能致癌食物——"二类致癌物",该报告由来自10个国家的22名专家在分析了800多份有关肉类饮食与癌症相关联的研究后得出相关结论。消息一经公布,立刻引起了广泛关注,人们纷纷追问:加工肉制品、红肉和癌症到底有什么关系?     

合理膳食、均衡搭配,加工肉制品并非不可吃

正10月26日,世界卫生组织正式发布消息,其下属国际癌症研究中心(IARC)将加工肉制品列入致癌食物名单——"一类致癌物",而且红肉本身也属于可能致癌食物——"二类致癌物",该报告由来自10个国家的22名专家在分析了800多份有关肉类饮食与癌症相关联的研究后得出相关结论。消息一经公布,立刻引起了广泛关注,人们纷纷追问:加工肉制品、红肉和癌症到底有什么关系?     

罗汉果内生菌的分离及α-淀粉酶抑制剂产生菌的筛选

该研究从广西龙胜县的罗汉果植株根中分离内生菌,并采用打洞法和Bernfeld法从中筛选出对α-淀粉酶具有抑制活性的菌株进行鉴定,进一步采用有机溶剂萃取发酵液后进行活性部位追踪。结果表明,从罗汉果根中分离得到10株内生菌,并从中筛选到2株α-淀粉酶抑制活性较高的菌株PD-3(42.51%)和PD-4(56.29%);两菌株的α-淀粉酶抑制活性物质均来自发酵液,发酵液经萃取后,菌株PD-3和PD-4抑制活性最高的萃取相分别为正丁醇相和乙酸乙酯相,对α-淀粉酶的抑制率分别为74.19%和88.46%,较阿卡波糖的抑制率(45.17%)高;菌株PD-3的正丁醇相含有多糖、黄酮等化学成分,菌株PD-4的乙酸乙酯相含有糖类、酚和醌等化学成分;两株菌株经形态观察均初步鉴定为青霉属(Penicillium),表明罗汉果内生真菌具有产α-淀粉酶抑制剂的潜力。     

Influence of operating conditions on membrane fouling in crossflow microfiltration of particulate suspensions

The effects of the operating conditions on the crossflow microfiltration (CFMF) of particulate suspensions were investigated. Lactalbumin particles were used as the feed material. Experiments were carried out in constant transmembrane pressure (TMP) mode using tubular ceramic membrane modules. All important parameters (internal and surface fouling, cake mass, height, porosity, and particle size distribution (PSD)) were estimated to provide a more complete understanding of the process than has been attempted before. Lactalbumin particles which are highly irregular in shape and widely size distributed formed an adhesive cake on the membrane surface during CFMF. The porosity and particle size of the deposited cake decreased with time of filtration. The value 100 kPa was found to be optimum with respect to the permeate flux in the studied range of TMP. Particle size classification effects of TMP and crossflow velocity (CFV) were demonstrated. The results of this study provided a possible explanation to the contradictory reports on the effect of CFV on the steady-state flux and the time required to obtain it. Significantly, the internal fouling first decreased with increasing CFV and then increased above 1.5 m s⁻¹. This is attributed to the particles size classification effect of CFV. A process was developed based on the observed effects of the operating parameters on the CFMF performance that enables operation at very low internal fouling and high flux for as long as 160 min. The developed process has the potential to become commercial if coupled with backflushing.     

异硫氰酸酯的产生、化学性质及测定方法

异硫氰酸酯是辣根、芥末及其制品的有效成分，其含量的多少是该类调味品主要的质量指标。异硫氰酸酯具有高度的生物活性，研究结果表明其具有杀菌、抑制血小板聚集、抗癌症和肿瘤等作用。吸引了众多食品化学、医药、生物学家的研究兴趣。本文从异硫氰酸酯的产生、化学性质及测定方法出发，对已有的研究成果进行了综述。     

The 1,2-benzenedithiole-based cyclocondensation assay: a valuable tool for the measurement of chemopreventive isothiocyanates

Many naturally occurring isothiocyanates (ITCs) show highly promising chemopreventive activities. Humans are commonly exposed to these compounds through the consumption of cruciferous vegetables which are the main source of dietary ITCs. Dietary ITCs may play an important role in cancer prevention and in the well-recognized cancer preventive activities of cruciferous vegetables. A generic analytical method, namely the 1,2-benzenedithiol-based cyclocondensation assay, was previously developed for quantitation of ITCs and their in vivo metabolites. This method has been widely used and has contributed greatly to research on chemoprevention by ITCs. In this article, the discovery and development of the cyclocondensation assay are recapitulated, and its sensitivity and specificity as well as its advantages and limitations are scrutinized. Moreover, detailed discussion is also provided to show how this assay has been used to advance our understanding of the cancer chemopreventive potential and the mechanism of action of ITCs.     

Response surface optimization and identification of isothiocyanates produced from broccoli sprouts

Isothiocyanates (ITCs) are proved as one of natural anticarcinogenic compounds, which are produced from the decomposition of glucosinolates by myrosinase. The present study optimized the enzymolysis conditions (pH, addition of EDTA and ascorbic acid) for ITCs production from glucosinolates in broccoli sprouts using response surface methodology. ITCs production was clearly enhanced by a suitable pH, addition content of EDTA and ascorbic acid. The optimal enzymolysis conditions were determined to be adding EDTA 0.02 mmol and 0.16 mg ascorbic acid to 4 ml of the homogenized phosphate–citrate buffer solution (pH 4.00). ITCs profiles were identified and seven kinds of individual ITCs were detected, among which sulforaphane accounted the most. Four kinds of individual ITCs including isobutyl isothiocyanate, 4-isothiocyanato-1-butene, 1-isothiocyanato-3-methyl-butane and 1-isothiocyanato-butane are firstly reported in broccoli sprouts.     

大孔树脂吸附异硫氰酸酯的动态相平衡研究

通过对大孔树脂吸附柱传质区的分析，测定了该树脂在特定条件下的传质区长度，并考查了异硫氰酸酯（ITCs）初始浓度、流速及树脂柱横截面积对传质区长度的影响，结果显示初始浓度和流速与传质区长度正相关；树脂柱横截面积是通过改变流速来影响传质区长度的。分析了装柱高度对树脂利用率的影响，当柱床高度介于传质区的2～3倍之间，对操作和吸附剂的利用率都较为有利。95％乙醇用于ITCs的洗脱速度快、效率高，洗脱后的树脂经简单再生后可重复使用，但吸附能力略有下降。     

Activated carbon cloth as anode for sulfate removal in a microbial fuel cell

By employing the sulfate-reducing bacterium Desulfovibrio desulfuricans we demonstrate the possibility of electricity generation in a microbialfuel cell (MFC) with concomitant sulfate removal. This approach is based on an in situ anodic oxidative depletion of sulfide produced by D. desulfuricans. Three different electrode materials, graphite foil (GF), carbon fiber veil (CFV), and high surface area activated carbon cloth (ACC), were evaluated for sulfide electrochemical oxidation. In comparison to CFV and GF electrodes, ACC was a superior materialfor sulfide adsorption and oxidation and showed significant potential for harvesting energy from sulfate-rich solutions in the form of electricity. Sulfate (3.03 g dm(-3)) was removed from a bacterial suspension, which represented 99% removal. A maximum power density of 0.51 mW cm(-2) (normalized to geometric electrode area) was obtained with a one-chamber, air-breathing cathode and continuous flow MFC operated in batch mode at 22 degrees C.     

Comparison of bioactive phytochemical content and release of isothiocyanates in selected brassica sprouts

The consumption of brassica sprouts as raw vegetables provides a fair amount of glucosinolates (GLs) and active plant myrosinase, which enables the breakdown of GLs into health-promoting isothiocyanates (ITCs). This study reports the determination of the main constituents related to human health found in edible sprouts of two Brassica oleracea varieties, broccoli and Tuscan black kale, and two Raphanus sativus varieties, Daikon and Sango. Radish sprouts exhibited the highest ability to produce ITCs, with Daikon showing the greatest level of conversion of GLs into bioactive ITCs (96.5%), followed by Sango (90.0%). Tuscan black kale gave a value of 68.5%, whereas broccoli displayed the lowest with 18.7%. ITCs were not the exclusive GL breakdown products in the two B. oleracea varieties, since nitriles were also produced, thus accounting for the lower conversion observed. Measuring the release of plant ITCs is a valuable tool in predicting the potential level of exposure to these bioactive compounds after the consumption of raw brassica sprouts.     

Microbiota: a mediator to transform glucosinolate precursors in cruciferous vegetables to the active isothiocyanates

Isothiocyanates (ITCs), such as sulforaphane (SFN), exhibit powerful biological functions in fighting cancers, and cardiovascular and neurodegenerative diseases. They normally exist as glucosinolates (GLSs) in cruciferous vegetables, which are not themselves bioactive until they are degraded by myrosinase to form ITCs. Myrosinase coexists in the same plants but is normally kept apart from GLSs in different apparatus. A key point is that myrosinase is temperature sensitive and can be inactivated upon exposure to temperatures over 60 °, as typically occurs during cooking. However, studies using animal models and population trials have suggested that human gut bacteria might act like an ‘organ’ in that they can secrete their own myrosinase. In this review, the hydrolysis of GLS by myrosinase is discussed, with an important focus on the gut microflora and their myrosinase‐producing roles. © 2017 Society of Chemical Industry