Oryzamutaic acid A, a novel yellow pigment from an Oryza sativa mutant with yellow endosperm

Oryzamutaic acid A, a novel yellow pigment, was isolated from the endosperm of an Oryza sativa mutant. The structure and absolute configuration of oryzamutaic acid A were elucidated on the basis of spectroscopic analysis, single-crystal X-ray diffraction analysis, and biogenetic reason. Oryzamutaic acid A might be biogenetically derived from four l-amino acids because it contains three amino acid groups and one amine group.     

Fuligoic acid, a new yellow pigment with a chlorinated polyene-pyrone acid structure isolated from the myxomycete Fuligoseptica f. flava

Fuligoic acid (1), a new yellow pigment with a chlorinated polyene-pyrone acid structure, was isolated from field-collected fruit bodies of the myxomycete Fuligoseptica f. flava, and its structure was elucidated by spectral data, including its absolute configuration based on CD data.     

Efficient synthesis of analogs of safflower yellow B, carthamin, and its precursor: two yellow and one red dimeric pigments in safflower petals

The synthesis of analogs (8, 12, 14) of two yellow pigments, safflower yellow B and the precursor of carthamin, and carthamin itself, a red pigment, which are produced in safflower (Carthamus tinctrious L.) petals and, which have a common dimeric quinochalcone structure, is reported. The key compound for the synthesis of these analogs, (p-hydroxycinnamoyl)filicinic acid (7) was synthesized in six steps from phloroglucinol in a total yield of 39%, which was reacted with 2,3,4,5,6-penta-O-acetyl-aldehydo-d-glucose, glyoxylic acid, and ethyl orthoformate in the presence of base to afford the corresponding analog, 8, 12, 14, in good yields, respectively. Precursor analog 12 was then converted to carthamin analog 14 by oxidative decarboxylation by treatment with potassium permanganate as well as the natural specimen.     

Identification and Characterization of the Yellow Pigment Synthesized by Cupriavidus sp. USMAHM13

Microbial pigments are gaining intensive attention due to increasing awareness of the toxicity of synthetic colours. In this study, a novel polymer-producing bacterium designated as Cupriavidus sp. USMAHM13 was also found to produce yellow pigment when cultivated in nutrient broth. Various parameters such as temperature, pH and ratio of culture volume to flask volume were found to influence the yellow pigment production. UV-Visible, Fourier transform infrared and ¹³C-nuclear magnetic resonance analyses revealed that the crude yellow pigment might probably represent new bioactive compound in the carotenoid family. The crude yellow pigment also exhibited a wide spectrum of antimicrobial activity against Gram-negative and Gram-positive bacteria with their inhibition zones and minimal inhibitory concentrations ranged from 25 to 38 mm and from 0.63 to 2.5 mg/ml, respectively. To the best of our knowledge, this is the first report on the identification and characterization of yellow pigment produced by bacterium belonging to the genus Cupriavidus.     

低速逆流色谱分离制备栀子黄色素中的藏花素

建立了低速逆流色谱技术(SRCCC)从栀子黄色素中快速分离制备藏花素的方法。两相溶剂系统由叔丁基甲基醚-正丁醇-乙腈-水(2:2.5:1:5, v/v/v/v)组成,以上相为固定相,下相为流动相。在转速为50 r/min和流速为5 mL/min的条件下,从5 g栀子黄色素粗样中分离得到2.47 g藏花素,纯度为96.8%。该方法制备量大、安全、高效,有可能成为工业级分离制备藏花素的一种有效手段。     

改进的QuEChERS方法结合液相色谱-串联质谱法测定腐竹和豆干中的二甲基黄和二乙基黄

建立了基于改进的QuEChERS方法结合液相色谱-串联质谱测定腐竹和豆干中二甲基黄和二乙基黄的方法。在2.0 g腐竹和豆干样品中加入5 mL水浸泡,然后加入10 mL乙腈提取,加入1.0 g NaCl、2.0 g无水硫酸镁进行液液分离;取1 mL提取液经50 mg N-丙基二乙胺分散固相萃取净化,经液相色谱分离、质谱测定,外标法定量。二甲基黄在添加水平为0.3、1和10 μg/kg时,方法的回收率为73.5%~84.5%;二乙基黄在添加水平为0.1、1和10 μg/kg时,方法的回收率为70.5%~81.2%;方法的相对标准偏差小于11%。二甲基黄的检出限和定量限分别为0.1 μg/kg和0.3 μg/kg,二乙基黄的检出限和定量限分别为0.05 μg/kg和0.1 μg/kg。该方法可以用于腐竹、豆干中二甲基黄和二乙基黄的快速筛查和定量分析。     

Enhanced thermal- and photo-stability of acid yellow 17 by incorporation into layered double hydroxides

2,5-dichloro-4-(5-hydroxy-3-methyl-4-(sulphophenylazo) pyrazol-1-yl) benzenesulphonate (DHSB) anions, namely acid yellow 17 anions, have been successfully intercalated into Zn-Al layered double hydroxides (LDH) to produce a novel organic-inorganic pigment by a simple method involving separate nucleation and aging steps (SNAS), and the dye-intercalated LDH was analyzed by various techniques, e.g., XRD, SEM, FT-IR, TG-DTA and ICP. The d-spacing of the prepared LDH is 2.09 nm. Furthermore, the incorporation of the DHSB aims to enhance the thermal- and photo-stability of the guest dye molecule, for example, the less color change after accelerated thermal- and photo-aging test.     

Investigating the influence of pH,temperature and agitation speed on yellow pigment production by Penicillium aculeatum ATCC 10409

In this study, the combined effect of pH, temperature and agitation speed on yellow pigment production and mycelial growth of Penicillium aculeatum ATCC 10409 was investigated in whey media. Different pH levels (5, 6.5 and 8), temperatures (25, 30 and 35°C) and agitation speed levels (100 and 150 rpm) were tested to determine the best conditions to produce a fungal yellow pigment under submerged fermentation. The best production of yellow pigment (1.38 g/L) was obtained with a pH value of 6.5, a temperature of 30°C and an agitation speed of 150 rpm. In contrast, the maximal biomass concentration (11.12 g/L) was obtained at pH value of 8, a temperature of 30°C and an agitation speed of 100 rpm. These results demonstrated that biomass and yellow pigment production were not directly associated. The identification of the structure of unknown P. aculeatum yellow pigment was detected using UV absorption spectrum and FT-IR spectroscopy.     

Cellulose microfibril orientation in onion (Allium cepa L.) epidermis studied by atomic force microscopy (AFM) and vibrational sum frequency generation (SFG) spectroscopy

Cellulose microfibril orientation in plant cell walls changes during cell expansion and development. The cellulose microfibril orientation in the abaxial epidermis of onion scales was studied by atomic force microscopy (AFM) and sum frequency generation (SFG) vibrational spectroscopy. Onion epidermal cells in all scales are elongated along the onion bulb axis. AFM images showed that cellulose microfibrils exposed at the innermost surface of the abaxial epidermis are oriented perpendicular to the bulb axis in the outer scales and more dispersed in the inner scales of onion bulb. SFG analyses can determine the orientation of cellulose microfibrils averaged over the entire thickness of the cell wall. We found that the average orientation of cellulose microfibrils inside onion abaxial epidermal cell walls as revealed by SFG is similar to the orientation observed at the innermost cell wall surface by AFM. The capability to determine the average orientation of cellulose microfibrils in intact cell walls will be useful to study how cellulose microfibril orientation is related to biomechanical properties and the growth mechanism of plant cell walls.     

Visualization of the nanoscale pattern of recently-deposited cellulose microfibrils and matrix materials in never-dried primary walls of the onion epidermis

For more than 10 years epidermal cell layers from onion scales have been used as a model system to study the relationship between cellulose orientation, cell growth and tissue mechanics. To bring such analyses to the nanoscale, we have developed a procedure for preparing epidermal peels of onion scales for atomic force microscopy to visualize the inner surface (closest to the plasma membrane) of the outer epidermal wall, with minimal disturbance and under conditions very close to the native state of the cell wall. The oriented, multilayer distribution of cellulose microfibrils, approximately ~3 nm wide, is readily observed over extended lengths, along with other features such as the distribution of matrix substances between and on top of microfibrils. The microfibril orientation and alignment appear more dispersed in younger scales compared with older scales, consistent with reported values for mechanical and growth anisotropy of whole epidermal sheets. These results open the door to future work to relate cell wall structure at the nm scale with larger-scale tissue properties such as growth and mechanical behaviors and the action of cell wall loosening agents to induce creep of primary cell walls.     

Isolation and structure elucidation of a novel yellow pigment from the marine bacterium Pseudoalteromonas tunicata

The marine environment is a major source for many novel natural compounds. A new yellow pigment has been isolated from the marine bacterium P. tunicata and identified as a new member of the tambjamine class of compounds. The structural identification was achieved by a combination of 1D and 2D-NMR spectroscopy and high resolution mass spectrometry data.     

内蒙古地区天然植物沙棘果中黄色素的提取工艺及性质研究

以内蒙古地区沙棘果实为原料，研究了提取黄色素的工艺条件，同时对该色素的性质进行了初步探讨。结果表明，以95％的乙醇溶液作浸提剂，提取的黄色素浓度最高，工艺流程简单易行，且无毒，无污染。对提取的黄色素进行的性质试验表明，沙棘黄色素对光、热具有较好的稳定性，适用于酸性或弱碱性的食品中，葡萄糖、氧化剂(H2O2)、还原剂(Na2SO3)等食品添加剂均无明显影响以上结果为这种优良天然色素的开发与应用提供了参考。     

Synthesis of optically active forms of (E)-6-isopropyl-3,9-dimethyl-5,8-decadienyl acetate,the pheromone of the yellow scale

Highly optically pure enantiomers of (E)-6-isopropyl-3,9-dimethyl-5,8-decadienyl acetate, the sex pheromone of the yellow scale (Aniodiella citrina), were stereoselectively from synthesized from(R)-(+)-citronellic acid. Only the (s)-enantiomer was bioactive.     

Effect of inorganic cores on dye properties of inorganic-organic hybrid pigments yellow 12

Some inorganic-organic hybrid pigments were fabricated by depositing pigment yellow 12(P.Y.12) on the surface of three inorganic cores with different particle size (white carbon black,microsilica,palygorskite). Effect of inorganic cores on the morphology and structure of the hybrid pigments were systematically investigated by nanoparticle analyzer, Fourier transforms infrared spectroscopy, and X-ray diffraction. Results showed that all three inorganic cores were encapsulated by the organic pigment. The particle size of hybrid pigments was all smaller and had narrower diameter scatter than the original pigment. The water dispersion and flow ability of these fabricated pigments were slightly improved. Thermal and UV-Vis analyses showed that the hybrid pigments had better thermo- and photo-stabilities. Additionally, the properties of the hybrid pigments including color strength, lightness, and yellow hue index were also improved and the modified pigment with white carbon black had the best coloring performance and better heat resistance than original P.Y.12.     

Medium dependant production of corymbiferone a novel product from Penicillium hordei cultured on plant tissue agar

Medium dependant production and the structure elucidation of corymbiferone (1) from the fungus Penicillium hordei grown on oatmeal and macerated tulip, yellow onion and red onion agars are reported. Compound 1 possesses an unusual oxygenated aromatic structure with a lactone bridge preventing full aromatization of the molecule, resulting in several unusual chemical shifts.     

固相萃取/液相色谱-串联质谱法测定食品中二甲基黄

建立了液相色谱-串联质谱(LC-MS/MS)测定食品中二甲基黄(DMY)的分析方法。样品经乙酸乙酯提取,二甲基黄专用固相萃取小柱(ProElut DMY SPE)净化,XDB-C18色谱柱(50 mm×4.6 mm,1.8μm)分离,并以5mmol/L乙酸铵水溶液(含0.1%(v/v)甲酸)-乙腈(含0.1%(v/v)甲酸)为流动相,梯度洗脱,电喷雾正离子模式(ESI~+)电离,多反应监测模式(MRM)检测,内标法定量。结果表明,DMY在0~50μg/L范围内线性关系良好,相关系数(r~2)均大于0.999。方法的检出限(LOD,S/N3)和定量限(LOQ,S/N10)分别为2μg/kg和10μg/kg。不同食品基质中,DMY在10、20和100μg/kg的添加水平下的平均加标回收率为93.3%~98.9%,相对标准偏差为1.6%~3.9%(n=6)。该方法有效补偿了液相色谱-串联质谱检测过程中的离子化抑制效应,灵敏度和准确度高,适用于腐乳、辣椒酱、禽蛋、豆干、糖果和火腿中DMY的测定。     

Effect of γ-irradiation on volatile compounds of dried Welsh onion (Allium fistulosum L.)

The volatile compounds of γ-irradiated dried Welsh onion were isolated by simultaneous distillation–extraction (SDE) technique and then analyzed by gas chromatography–mass spectrometry (GC–MS) along with their non-irradiated counterparts. A total of 35 volatile compounds were identified in non-irradiated and 1 kGy irradiated samples and 36 volatile compounds were identified in 3, 5, 10 and 20 kGy irradiated samples so far belong to chemical classes of acid, alcohol, aldehyde, ester, furan, ketone and S-containing compound. S-containing compounds were detected as major volatile compounds of all experimental samples. Though the content of several compounds was increased after irradiation, content of major S-containing compounds was found to decreased in the process. Application of high-dose irradiation if required for microbial decontamination of dried Welsh onion is feasible as it enhanced the total concentration of volatile compounds by 31.60% and 24.85% at 10 and 20 kGy, respectively.     

Adsorption of acid yellow dye on flakes of chitosan prepared from fishery wastes

Chitosan flakes, extracted from prawns and labeo rohita scales, with high adsorption capacity were prepared after chemical treatment and were used to remove acid yellow dye from water. The results showed that adsorption capacity is dependent on pH, initial concentration of dye, BET, Langmuir surface area and pore volume of the adsorbent. In acidic conditions, the polymer amino groups were protonated (positively charged polymer chain), which showed attraction with negative ions of anionic dye. Chitosan from prawns scales showed higher dye adsorption under the same experimental conditions. Adsorption isotherms were developed and equilibrium data fitted well to Langmuir and Freundlich isotherm models.     

New compounds obtained by enzymatic oxidation of phloridzin

Oxidation of phloridzin was studied in a model system in the presence of apple polyphenol oxidase. In addition to 3-hydroxy phloridzin, two major oxidation products were purified by reversed phase HPLC at the semi-preparative scale. Their structures were elucidated by UV, ESI-MSⁿ and NMR spectroscopies. The first compound was a colourless product, whose novel structure strongly differs from its precursor showing a biphenyl moiety and a propionic acid chain. The second product was an oxidised form of the first one and corresponded to a stable yellow pigment with two isomeric forms. A mechanism of formation of these products, which implied successive oxidation and nucleophilic addition steps was proposed.     

Identification of lead pigments in nanosamples from ancient paintings and polychromed sculptures using voltammetry of nanoparticles/atomic force microscopy

Voltammetry of nanoparticles coupled with atomic force microscopy was used to identify lead pigments in nanosamples proceeding from works of art. Upon mechanical attachment of few nanograms of sample to a graphite plate, well-defined voltammetric responses were obtained for lead orange, lead yellow, lead white, litharge, minium, Naples yellow, and tin-lead yellow, allowing for an unambiguous identification of such pigments. Atomic force images provide evidence for the occurrence of pigment-characteristic reduction processes accompanied by metal deposition on the graphite substrate. Electrochemical parameters are used for pigment identification. Application to the method for identifying lead pigments in different model binder + pigment specimens and pictorial samples from the canvas painting collection (anonymous, 17th century) of the Saint Joseph Church in Taormina (Italy), the frescoes painted by Antonio Acisclo Palomino y Velasco (1698) in the vault of the Sant Joan del Mercat church in València (Spain) and an anonymous polychromed sculpture (16th century) representing a Martyr Saint from Alacant (Spain) is described.