毛细管电泳法测定石榴皮中鞣花酸与安石榴苷含量

建立了毛细管电泳紫外检测法测定石榴皮中鞣花酸和安石榴苷含量的方法,并对不同产地石榴中的石榴皮鞣花酸和安石榴苷含量进行测定。研究了运行缓冲液pH值和浓度、运行电压等对电泳的影响,得到最优化的测定条件为:50 mmol/L的硼砂-硼酸缓冲液(pH 8.7),分离电压20 kV,电动进样9 s/20 kV。在最优条件下,检测波长260 nm,上述两种组分可在12 min内完全分离。结果显示,鞣花酸和安石榴苷的线性范围分别为5.0×10-7～5.0×10-5g/mL和2.0×10-6～5.0×10-5g/mL,检出限分别为1.0×10-7g/mL和1.3×10-6g/mL,峰面积的相对标准偏差(RSD,n=7)分别为2.4%和2.2%,平均回收率分别为101%和98%。采用高效液相色谱法进行比对,t-检验表明两组数据无显著性差异。该法简便、快速、准确,已成功应用于实际样品的测定。     

高效液相色谱测定石榴皮水提取物中4种多酚化合物的含量

建立了石榴皮水提取物中没食子酸、安石榴甙A、安石榴甙B和鞣花酸4种多酚化合物的高效液相色谱(HPLC)分析方法.样品经前处理并过滤后,采用HPLC检测,外标法定量.在最佳分析条件下,上述4种多酚化合物的线性范围分别为7.48 ～ 149.50、15.36～153.55、27.65 ～276.45、7.13 ～ 114....     

八碳环化合物的化学

由八个碳原子所组成的八碳环化合物,是有机化学中较新的一部分;关于他们的化学研究,在普通的有机化学中很少谈到。八碳环化合物的衍生物存在于自然界的某些生物碱中。例如,假石榴皮碱、甲基安石榴酮等。八碳环化合物很不安定,和萜类化合物一样,容易发生重排反应。因此,八碳环物质就具有许多我们没有见过的特殊反应。本篇主要是根据 L.E.Craig.的论文写成的。     

响应面法优化石榴叶多酚闪式提取的工艺研究

为建立快捷、高效、绿色的石榴叶多酚的提取工艺,通过单因素实验确定其主要影响因素,在单因素实验的基础上利用响应面法进行分析,确定提取石榴叶多酚的最佳提取条件为:乙醇浓度58%、料液比1∶9 (g/mL),提取时间4 min,在此条件下石榴叶多酚的理论提取量为:29.37 g GAE/100 g,实际提取量为:29.12 g GAE/100 g.     

石榴籽中脂肪酸成分分析

采用两种方法对石榴籽中的脂肪酸进行了甲酯化,所得脂肪酸甲酯经GC-MS分析.方法一共检测出14种脂肪酸,主成分为油酸、亚油酸、山嵛酸、棕榈酸、硬脂酸和二十碳烯酸;方法二共检测出24种脂肪酸,主成分为棕榈酸、硬脂酸、花生酸、山嵛酸、油酸、亚油酸、二十碳烯酸等.其中的山嵛酸等多种饱和脂肪酸均为首次从石榴籽中鉴定出.     

火焰原子吸收光谱法测定石榴籽中微量元素

石榴为石榴科石榴属落叶灌木或小乔木植物,我国栽培的石榴品种达100多种,按口感又可分为甜石榴和酸石榴。石榴的根、叶、花、果实、果皮、种子均可入药。石榴资源开发的重点是生产石榴饮料、酒以及营养保健品,石榴可食部分占其总量的15%～40%,是生食佳品和制造饮料、果酒的好原料。石榴籽嚼碎时味香、无毒,可调理胃火、消食、     

黄芩苷与人血清白蛋白的相互作用研究

利用紫外光谱、荧光光谱、傅立叶红外谱、圆二色谱及分子模型等技术,在生理pH条件下,研究了黄芩苷与人血清白蛋白(HSA)的相互作用,并计算了其结合常数和热力学参数.分子模型研究表明,黄芩苷与HSA在亚结构域ⅡA结合,二者间的作用主要为静电作用和疏水作用,与荧光光谱结果基本一致.红外光谱和圆二色谱显示黄芩苷与HSA结合后未...     

快速微乳电动毛细管色谱法同时测定忍冬藤中11种有效成分

1 引言 忍冬藤为忍冬科植物忍冬(Lonicera japonica Thunb.)的干燥茎枝,产于我国大部分地区.忍冬藤具有抗炎、预防和治疗肝纤维化、止血、抗病毒等功效.目前,分析评价忍冬藤质量的方法主要有分光光度法、高效液相色谱法.本研究采用快速的微乳电动毛细管色谱法同时分离并测定了忍冬藤药材中的马钱子苷、当药苷、绿原酸等11种有效成分.     

黄酮苷的合成研究进展

黄酮苷广泛存在于自然界植物,具有广泛的药理活性和潜在的药用价值,其合成方法值得研究,对2014年至2018年黄酮苷的合成进行综述.黄酮苷的合成主要包括化学合成和生物合成两大类,而化学合成又分为全合成和半合成,其中全合成主要有β-丙二酮酸化关环法(Baker-Venkataraman,BK-VK法)和查尔酮氧化关环法(Algar-FlynnOyamada, AFO法)两种经典方法;半合成是以芦丁、槲皮素、山萘酚、柚皮素等天然黄酮为原料.黄酮氧苷的化学合成目前常用的方法有三种:Koening-Knorr法、相转移催化法、糖基三氯乙酰亚胺酯法.黄酮碳苷的糖苷链的连接主要是通过O→C重排法.酶催化生物合成法目前常用的酶是糖基转移酶和糖苷合酶这两种酶.     

电喷雾串联质谱研究黄芩苷与谷胱甘肽的相互作用

建立了研究黄芩苷和谷胱甘肽的相互作用的电喷雾多级串联质谱方法,结果表明黄芩苷首先自氧化生成黄芩苷半醌,随后黄芩苷半醌与谷胱甘肽进一步发生反应,生成谷胱甘肽与黄芩苷加合物,该化合物不稳定,可进一步发生自氧化、水合反应或脱糖醛酸等反应.利用串联质谱技术鉴定了谷胱甘肽与黄芩苷的结合位点是在黄芩苷苷元的C8位.该方法从分子水平...     

Cost‐effective imprinting combining macromolecular crowding and a dummy template for the fast purification of punicalagin from pomegranate husk extract

The combination of molecular crowding and virtual imprinting was employed to develop a cost‐effective method to prepare molecularly imprinted polymers. By using linear polymer polystyrene as a macromolecular crowding agent, an imprinted polymer recognizable to punicalagin had been successfully synthesized with punicalin as the dummy template. The resulting punicalin‐imprinted polymer presented a remarkable selectivity to punicalagin with an imprinting factor of 3.17 even at extremely low consumption of the template (template/monomer ratio of 1:782). In contrast, the imprinted polymer synthesized without crowding agent, did not show any imprinting effect at so low template amount. The imprinted polymers made by combination of molecular crowding and virtual imprinting can be utilized for the fast separation of punicalagin from pomegranate husk extract after optimizing the protocol of solid‐phase extraction with the recovery of 85.3 ± 1.2%.     

Quantitative CE analysis of punicalagin in Combretum aculeatum extracts traditionally used in Senegal for the treatment of tuberculosis

Mycobacterium tuberculosis is the causative agent of tuberculosis, an infectious bacterial disease, which most commonly affects the lungs. In the search for novel active compounds or medicines against tuberculosis, an ethnopharmacological survey combined with a host‐pathogen assay has recently highlighted the potency of an aqueous extract of Combretum aculeatum. C. aculeatum is used in traditional medicine and has demonstrated a significant in vitro antimycobacterial activity. Punicalagin, an ellagitannin, was isolated and found to be related to the biological activity of the extract. An analytical method for the evaluation of punicalagin in C. aculeatum was developed by capillary electrophoresis. After method optimization, the quantification of punicalagin was achieved for the evaluation of various plant extracts to determine the content of punicalagin related to the extraction modes and conditions, origin of the plant material, and harvesting period. The developed method demonstrated that the leaves presented the highest punicalagin content compared to the seeds and stems. A decoction of 30 min in boiling water was found to be the best extraction mode of C. aculeatum.     

Development of analytical method for the quality control of the fruit bark of Punica granatum L. (pomegranate) and antichemotatic activity of extract and rich fraction in punicalagins

Pomegranate is of current interest owing to the existing potential for industrial uses of fruit peels. This includes its availability as a raw vegetable material, a byproduct that constitutes residue in the use of the species and is recognized as a functional product, and beneficial health properties, as will be demonstrated in the studies cited. Therefore, it is necessary to ensure its effectiveness and safety. Toward this end, the aim of this study was to develop and validate an analytical method for the separation and quantification of total punicalagin present in the bark of the fruit of Punica granatum by HPLC. Purity tests such as water determination and total ashes were also performed. The ability of the extract and enriched fraction of punicalagin to inhibit leukocyte migration in vitro was determined by the Boyden's chamber method. The developed HPLC method demonstrated good separation and quantification of the punicalagin α and β anomers. The method is efficient and reliable, and can ultimately be used for the analysis of the extract of pomegranate. The crude extract and the fraction of punicalagins significantly inhibited leukocyte migration at concentrations of 1 and 10 μg/mL in relation to the negative control, indicating potential antichemotactic action.     

Determination of Punicalagin Isomers in Pomegranate Husk

Punicalagins are the main ingredients of phenolic compounds in pomegranate (Punica granatum L.) husk. A simple and accurate method for punicalagin analysis based on ethanol extraction and RP-LC using linear gradient of methanol in 0.1% TFA solution was established. The feasibility of this procedure was tested by analyzing the punicalagin level both in fresh pomegranate husk collected from different provinces in China and dried husk from a drugstore. The content of each isomer and total content of punicalagins in husk were determined. The mean value of punicalagins content in pomegranate husk was 82.4 mg g^?1. The highest content of punicalagins was found in a variety of husks from Shanxi province, while the lowest content was found in the husk from the drugstore in Guangdong province.     

NMR assignments and the acid–base characterization of the pomegranate ellagitannin punicalagin in the acidic pH-range

In exploring the capability of nuclear magnetic resonance (NMR) spectroscopy for pomegranate juice analysis, the eight aromatic singlet resonances of α- and β-punicalagin were clearly identified in the ¹H NMR spectra of juice samples. The four downfield resonances were found to be sensitive to small pH changes around pH 3.50 where the NMR spectra of the juice samples were recorded. To understand this unusual behavior, the ¹H and ¹³C resonance assignments of the punicalagin anomers were determined in aqueous solution and pH titrations with UV and ¹H NMR detection carried out to characterize the acid–base properties of punicalagin over the pH range 2–8. Simultaneous fitting of all of the pH-sensitive ¹H NMR signals produced similar but significantly different pK _a values for the first two deprotonation equilibria of the gallagic acid moiety of the punicalagin α- (pK _a1?=?4.57?±?0.02, pK _a2?=?5.63?±?0.03) and β- (pK _a1?=?4.36?±?0.01, pK _a2?=?5.47?±?0.02) anomers. Equivalent pK _a values, (α?:?6.64?±?0.01, β?:?6.63±?0.01) were measured for the third deprotonation step involving the ellagic acid group, in good agreement with a prior literature report. The punicalagin anomer equilibrium readjusts in parallel with the proton dissociation steps as the pH is raised such that β-punicalagin becomes the most abundant anomer at neutral pH. The unusual upfield shifts observed for the glucose H3 and H5 resonances with increasing pH along with the shift in the α/β anomer equilibrium are likely the consequence of a conformational rearrangement.

Effects of Green Tea Powder,Pomegranate Peel Powder,Epicatechin and Punicalagin Additives on Antimicrobial,Antioxidant Potential and Quality Properties of Raw Meatballs

Alternative technologies, which have been developed in order to meet the consumers’ demand for nourishing and healthy meat and meat products, are followed by the food industry. In the present study, it was determined, using the HPLC method, that green tea contains a high level of epicatechin (EP) under optimal conditions and that pomegranate peel contains a high level of punicalagin (PN). Green tea, pomegranate peel, EP and PN were added to meatballs at different concentrations in eight groups. The antioxidant capacities of extracts were measured. The antimicrobial activity was examined for 72 h using three different food pathogens. The highest level of antimicrobial activity was achieved in the 1% punicalagin group, whereas the minimum inhibition concentration (L. monocytogenes, S. typhimurium) was found to be 1.87 mg/mL. A statistically significant decrease was found in FFA, POV and TBARS levels of meatballs on different days of storage (p < 0.05). When compared to the control group, the bioactive compounds preserved the microbiological and chemical properties of meatballs during storage at +4 °C (14 days). It was concluded that the extracts with high EP and PN concentrations can be used as bio-preservative agents for meat and meat products.     

Carbon molecular sieve based micro‐matrix‐solid‐phase dispersion for the extraction of polyphenols in pomegranate peel by UHPLC‐Q‐TOF/MS

A rapid, simple, and efficient sample extraction method based on micro‐matrix‐solid‐phase dispersion (micro‐MSPD) was applied to the extraction of polyphenols from pomegranate peel. Five target analytes were determined by ultra‐HPLC coupled with Q‐TOF/MS. Carbon molecular sieve (CMS) was firstly used as dispersant to improve extraction efficiency in micro‐MSPD. The major micro‐MSPD parameters, such as type of dispersant, amount of dispersant, grinding time, and the type and the volume of elution solvents, were studied and optimized. Under optimized conditions, 26 mg of pomegranate peel was dispersed with 32.5 mg of CMS, the grinding time was selected as 90 s, the dispersed sample was eluted with 100 μL of methanol. Results showed that the proposed method was of good linearity for concentrations of analytes against their peak areas (coefficient of determination r² > 0.990), the LOD was as low as 3.2 ng/mL, and the spiking recoveries were between 88.1 and 106%. Satisfactory results were obtained for the extraction of gallic acid, punicalagin A, punicalagin B, catechin, and ellagic acid from pomegranate peel sample, which demonstrated nice reliability and high sensitivity of this approach.     

Simultaneous LC-DAD and LC-MS Determination of Ellagitannins, Flavonoid Glycosides, and Acyl-Glycosyl Flavonoids in Cistus salvifolius L. Leaves

A rapid and inexpensive HPLC method has been developed for simultaneous separation of the three main classes of polyphenol in the leaves of Cistus salvifolius L. Time devoted to extraction of polyphenols, which was performed using small volume of solvent, did not exceed 120 min. We identified three ellagitannins (punicalagin and related compounds), a total of ten glycosyl derivatives of quercetin and myricetin, and two coumaroyl glucosyl kaempferols by use of both diode-array detection (DAD) and mass spectrometry. The polyphenol composition of C. salvifolius leaves, which may contribute to the metabolic plasticity of the species, may explain its distribution in infertile soils of the Mediterranean area, and may also indicate this shrub is an important source of metabolites of potential use in human health care.     

Biological activities of phenolic compounds isolated from galls of Terminalia chebula Retz. (Combretaceae)

The aqueous extract of galls from Terminalia chebula Retz. (Combretaceae) was fractionated on Diaion and refractionated on octadecyl silica column. Six phenolic compounds were isolated and identified as gallic acid (1), punicalagin (2), isoterchebulin (3), 1,3,6-tri-O-galloyl-β-D-glucopyranose (4), chebulagic acid (5) and chebulinic acid (6). All of the compounds showed stronger 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and melanin inhibitory activities than ascorbic acid, butylated hydroxytoluene, α-tocopherol, arbutin and kojic acid, the reference compounds. Gallic acid (1) exhibited inhibitory activity against nitric oxide production in lipopolysaccharide-activated macrophages. However, all isolated compounds exhibited less activity than the reference compounds in mushroom tyrosinase inhibition and human tumour cytotoxicity assays. This study has demonstrated that the phenolic compounds isolated from galls of T. chebula might contribute significantly due to their antioxidant and whitening activities.