Isolation and structural identification of the main anthocyanin monomer in Vitis amurensis Rupr

Many types of anthocyanins are present in Vitis amurensis Rupr of ‘Beibinghong’, which is grown in North-east China and has high antioxidant activity. However, the anthocyanin with the highest content in V. amurensis Rupr has not yet been identified. In this study, pulsed electric field extraction and semi-preparative liquid phase separation were used to isolate the anthocyanin monomer from ‘Beibinghong’. UV–vis spectroscopy, FTIR spectroscopy, mass spectra and nuclear magnetic resonance were used to identify the anthocyanin monomer. The antioxidant activities of the anthocyanin monomer were also analysed. Malvidin-3,5-O-diglucoside was identified as the main anthocyanin in V. amurensis Rupr, which could be used as a raw material for its extraction. Furthermore, malvidin-3,5-O-diglucoside can be potentially used as a functional food, and a novel therapeutic and preventive agent for oxidative stress-related diseases. This study provides technical information for the future purification and structural identification of anthocyanins.     

Contribution à la phytochimie du genre Gentiana,XIX. Identification de nouveaux C-glucosides flavoniques dans Gentiana pyrenaicaL

Phytochemistry of genus Gentiana, XIX: Identification of new C-glycosylflavones in Gentiana pyrenaica L . Five flavone C-glucosides [6-C-β-D -glucopyranosyl-tricine ( 1 ) or isopyrenine; 7-O-β-D -glucopyranosyl-6-C-β-D -glucopyranosyltricine ( 2 ) or isopyrenine-7-O-glucoside; isoscoparine-7-O-glucoside ( 3 ); 7-O-β-D -glucopyranosyl-6-C-β-D -glucopyranosylacacetine ( 4 ) and isovitexine-7-O-glucoside ( 5 ) or saponarine] as well as the flavonol glucoside isoquercitrine ( 9 ) have been isolated chromatographically, using polyamide and cellulose columns, from the aerial parts of Gentiana pyrenaica L . 1 and 2 are new compounds and the first glycoflavones trisubstituted on cycle B. Compound 4 is also encountered for the first time in nature.     

Gamma irradiation affects the total phenol,anthocyanin and antioxidant properties in three different persian pistachio nuts

The effects of gamma irradiation (GR) on total phenol, anthocyanin and antioxidant activity were investigated in three different Persian pistachio nuts at doses of 0, 1, 2 and 4 kGy. The antioxidant activity, as determined by FRAP and DPPH methods, revealed a significant increase in the 1–2 kGy dose range. Total phenol content (TPC) revealed a similar pattern or increase in this range. However, when radiation was increased to 4 kGy, TPC in all genotypes decreased. A radiation dose of 1 kGy had no significant effect on anthocyanin content of Kale-Ghouchi (K) and Akbari (A) genotypes, while it significantly increased the anthocyanin content in the Ghazvini (G) genotype. In addition, increasing the radiation to 4 kGy significantly increased the anthocyanin content of K and G genotypes. To conclude, irradiation could increase the phenolic content, anthocyanin and antioxidant activity of pistachio nuts.     

Purification and antioxidant capacity analysis of anthocyanin glucoside cinnamic ester isomers from Solanum nigrum fruits

In a recent study, anthocyanins, which have a strong free radical‐scavenging activity, were examined for their potential to effectively prevent cancer. However, clinical trials are limited by the purity of the anthocyanin. Multiple methods are used to extract and purify anthocyanins. Based on previous work on Solanum nigrum, which is a widely distributed plant, in this study, DM130 macroporous resin, Sephadex LH20, and a C18 column were used to separate cis–trans anthocyanin isomers. These anthocyanins constitute the majority of total S. nigrum anthocyanins. The results showed that this “DM130‐LH20‐C18 system” can be used to obtain a cinnamic acid‐derived cis–trans anthocyanin, petunidin‐3‐(p‐coumaroyl)‐rutinoside‐5‐glucoside, with a purity of 98.5%, for effective quantitation. In order to determine the antioxidant ability of the petunidin‐3‐(p‐coumaroyl)‐rutinoside‐5‐glucoside cis–trans isomers, three ordinary methods were adopted. The maximum antioxidant ability of the cis–trans anthocyanin was dozens of times higher than that of vitamin C.     

Simultaneous Analysis of Seven Bioactive Compounds in Sambucus Chinensis Lindl by HPLC

Following optimization of extraction, separation, and analytical conditions, a simple, rapid, and sensitive HPLC-UV method was developed for the simultaneous determination of seven major bioactive components in Sambucus chinensis Lindl, including chlorogenic acid, caffeic acid, p-coumaric acid, ferulic acid, kaempferol-3-O-β-D-galactopyranoside, kaempferol-3-O-β-D-glucopyran-oside, and kaempferol-3-O-(6-actyl)-β-D-galacto-pyranoside. The good chromatographic separation was performed on a Gemini C₁₈ reversed-phase analytical column (250 mm × 4.6 mm, 5 μm) by gradient elution with acetonitrile and formate aqueous buffer (containing 0.8% formic acid, V/V) at a flow rate of 1.0 mL/min. The detection wavelength was set at 326 nm. The intra-day and inter-day precisions were evaluated with the R.S.D. values less than 4.0%. The mean recoveries of the seven compounds were in the range of 92.4%–104.8%. The method was successfully applied to determine the seven bioactive compounds in six different origins of Sambucus chinensis Lindl samples, and there was a significant variation in the contents of the seven compounds among the six samples. Therefore, this method provided a new basis of overall assessment for routine use in the quality control of Sambucus chinensis Lindl.     

Specific Poly-phenolic Compounds in Cell Culture of <Emphasis Type="Italic">Vitis vinifera</Emphasis> L. cv. Gamay Fréaux

Cell cultures established from plants represent an attractive alternative to whole plants for effective production of bioactive secondary metabolites. Cell culture from Vitis vinifera L. cv. Gamay Fréaux accumulated high amounts of hydroxycinnamic acid derivatives and anthocyanins. Two new compounds were identified: 3-O-glucosylresveratrol, a stilbene derivative, abundant in cell suspension culture, and a hydroxyphenol, 4-(3,5-dihydroxyphenyl)-phenol, abundant in callus culture. The major anthocyanin monoglucosides present in cell suspension culture were cyanidin 3-O-glucoside and peonidin 3-O-glucoside, and the major cinnamoyl derivatives were cyanidin 3-O-p-coumaryl glucoside and peonidin 3-O-p-coumaryl glucoside. Three minor anthocyanin compounds were found in V. vinifera cell culture: delphinidin 3-O-glucoside, petunidin 3-O-glucoside, and delphinidin 3-O-p-coumaryl glucoside. Anthocyanin levels of cell suspension cultures increased significantly—about eight fold—after 4-day cultivation in new medium. Salicylic acid at a concentration of 50 μM did not enhance anthocyanin accumulation in cell suspension culture, and similar levels of jasmonic acid significantly reduced the anthocyanin content.     

Statistical optimization of an RP‐HPLC method for the determination of selected flavonoids in berry juices and evaluation of their antioxidant activities

An isocratic RP‐HPLC method for the separation and identification of selected flavonoids (quercetin, rutin, luteolin‐7‐O‐glucoside, kaempferol and kaempferol‐3‐O‐glucoside) in commercial berry juices (blackcurrant, blueberry, red raspberry and cherry) was developed with the aid of central composite design and response surface methodology. The optimal separation conditions were a mobile phase of 85:15 (% v/v) water–acetonitrile, pH 2.8 (adjusted with formic acid), flow rate 0.5 mL min⁻¹ and column temperature 35°C. The obtained levels of bioflavonoids (mg per 100 mL of juice) were as follows: for quercetin, ca. 0.21–5.12; for kaempferol, ca. 0.05–1.2; for rutin, ca. 0.4–6.5; for luteolin‐7‐O‐glucoside, ca. 5.6–10.2; and for kaempferol‐3‐O‐glucoside, ca. 0.02–0.12. These are considerably lower than the values in fresh fruits. Total phenolic, flavonoid and anthocyanin contents were determined spectrophotometrically. Total flavonoid content varied as follows: blackcurrant > blueberry > red raspberry > cherry. The antioxidant activity of juice extracts (DPPH and ABTS methods) expressed as IC₅₀ values varied from 8.56 to 14.05 mg L⁻¹. These values are ~2.5–3 times lower than quercetin, ascorbic acid and Trolox®, but compared with rutin and butylhydroxytoluene, berries show similar or better antioxidant activity by both the DPPH and ABTS methods.     

Identification of Anthocyanin Compounds in Butterfly Pea Flowers (Clitoria ternatea L.) by Ultra Performance Liquid Chromatography/Ultraviolet Coupled to Mass Spectrometry

Butterfly pea flower have great sensory attraction, but they have not yet been used widely in Vietnam. Extracts of butterfly pea flowers can be used conveniently as a natural blue colorant for food products. In this study, the identification of anthocyanin compounds in butterfly pea flowers was performed by UPLC coupled with a UV and Mass spectrometer instrument. Positive and negative ion electrospray MS/MS chromatograms and spectra of the anthocyanin compounds were determined. By analyzing the chromatograms and spectra for each ion, five anthocyanins were identified in the butterfly pea flower extract; these were delphinidin-3-(6″-p-coumaroyl)-rutinoside, cyanidin 3-(6″-p-coumaroyl)-rutinoside, delphinidin-3-(p-coumaroyl) glucose in both cis- and trans- isomers, cyanidin-3-(p-coumaroyl-glucoside) and delphinidin-3-pyranoside. Additionally, based on their intensity, it was determined that cyanidin-3-(p-coumaroyl-glucoside) was the most abundant anthocyanin, followed by cyanidin 3-(6″-p-coumaroyl)-rutinoside, delphinidin-3-(p-coumaroyl-glucoside), delphinidin-3-(6″-p-coumaroyl)-rutinoside and delphinidin-3-pyranoside. In this study, cyanidin derivatives were discovered in butterfly pea flower extract, where these compounds had not been detected in previous studies.     

高效液相色谱/电喷雾-离子阱-飞行时间质谱分析鉴定中药虎杖中的主要化学成分

建立了快速、准确鉴别中药虎杖中化学成分的液相色谱-质谱法。采用高效液相色谱/电喷雾-离子阱-飞行时间质谱(HPLC/ESI-IT-TOF MS)对蒽醌类以及羟基二苯乙烯类对照品,包括大黄素、大黄酚、大黄素甲醚、大黄酸、芦荟大黄素和虎杖苷进行了分析,总结其多级裂解规律。建立了虎杖甲醇提取物的液相色谱分离条件及质谱检测条件,根据负离子模式下获得的各组分多级质谱数据,对比对照品碎裂特征并参考文献,对主要色谱峰进行指认,共鉴别了10个化合物,包括白藜芦醇-4′-O-葡萄糖苷、虎杖苷、大黄素-8-O-葡萄糖苷、白藜芦醇、决明松-8-O-葡萄糖苷、大黄素-1-O-葡萄糖苷、决明松-8-O-(6′-乙酰基)葡萄糖苷、大黄素甲醚-8-O-葡萄糖苷、大黄素甲醚-8-O-(6′-乙酰基)葡萄糖苷和大黄素,其中决明松-8-O-(6′-乙酰基)葡萄糖苷和大黄素甲醚-8-O-(6′-乙酰基)葡萄糖苷为虎杖中新发现的成分。研究结果表明,在中药化学成分研究工作中,采用电喷雾-离子阱-飞行时间质谱可提高中药化学成分的分析效率并有利于新化合物的发现和鉴别。     

Reversed‐Phase High‐Performance Liquid Chromatography with Electrochemical Detection of Anthocyanins

Abstract

Anthocyanins, flavonoid compounds present in grapes and wines, were determined by reverse‐phase high‐performance liquid chromatography (RP‐HPLC) with electrochemical detection (RP‐HPLC‐ED). The method developed consists of RP‐HPLC gradient elution with voltammetric detection using a glassy carbon electrode after separation in an Inertsil ODS‐3V analytical column. Good peak resolution was obtained following direct injection of a 50 µL sample of anthocyanins in a mobile phase of pH 2.20. The results show that six different anthocyanins: cyanidin‐3‐O‐glucoside chloride (kuromanin chloride), cyanidin‐3,5‐di‐O‐glucoside chloride (cyanin chloride), malvidin‐3‐O‐glucoside chloride (oenin chloride), malvidin‐3,5‐di‐O‐glucoside chloride (malvin chloride), delphinidin‐3‐O‐glucoside chloride (myrtillin chloride), and peonidine‐3‐O‐glucoside chloride, all with antioxidant properties, can be separated in a single run by direct injection of solution. The limit of detection (LOD) for these compounds was lower than 0.3 µM. The method can also be applied to the analysis of these compounds in red wines and in skins and pulp extracts of red grapes, since all these antioxidants are electroactive.     

An improved method for the analysis of major antioxidants of Hibiscus esculentus Linn

Major antioxidants of aqueous ethanol extract from Lady's Finger (Hibiscus esculentus Linn) were systematically investigated in this study. Firstly, high-performance liquid chromatography (HPLC) was applied to identify antioxidant peaks in a sample by spiking the sample extract with 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical, which was prepared from manganese dioxide and ABTS. Secondly, in order to identify the elution period of major antioxidant peaks, the antioxidant capacities of different fractions from solid-phase extraction (SPE) were measured, and the chromatograms of fractions were also recorded. Lastly, multiple mass spectrometry (MS(n)) was used to elucidate the possible chemical structures of antioxidants, and nuclear magnetic resonance (NMR) was further applied for structure confirmation. The major antioxidant compounds in lady's finger were identified to be quercetin derivatives and (-)-epigallocatechin using HPLC-MS and HPLC-MS(n) (n = 2-4) techniques. It was found that about 70% of total antioxidant activity was contributed by four quercetin derivatives. The structures of major antioxidants, which were isolated by semi-preparative RP-HPLC with two tandem C18 columns, were further confirmed using UV-vis absorption spectroscopy and 13C NMR spectra. Quercetin 3-O-xylosyl (1' --> 2') glucoside, quercetin 3-O-glucosyl (1' --> 6') glucoside, quercetin 3-O-glucoside and quercetin 3-O-(6'-O-malonyl)-glucoside were first identified and characterized as major antioxidants in lady's finger.     

Phytochemical constituents and antioxidant activity of Echinops albicaulis

Two thiophenes; 5-(3-buten-1-ynyl)-2,2′-bithiophene (2) and α-tertthienyl (9), two alkaloids; echinopsine (10) and echinorine (11), three flavonoids; genkwanin (5), apigenin (6), and rutin (7), two triterpenoids; lupeol acetate (1) and lupeol linoleate (4), together with 2,6,10-trimethyldodeca-2,6,10-triene (4) and β-sitosterol glucoside (8) were isolated from the aerial parts of Echinops albicaulis. Antioxidant, antimicrobial and antiprotozoal activities were evaluated. E. albicaulis aqueous methanolic extract (50, 10, and 1 mg/mL) showed significant antioxidant activity comparable to the potent antioxidant, N-acetyl cysteine, moreover, the aqueous methanolic extract (1 mg/mL) significantly reduced intracellular reactive oxygen species in active cell cultures of human peripheral blood mononuclear cells under oxidative stress more than the reference antioxidant N-acetyl cysteine. None of the isolated compounds showed antimicrobial or antiprotozoal activities at concentration up to 20 μg/mL.     

Separation of Delphinidin-3-O-sambubioside, Cyanidin-3-O-sambubioside and p-Coumaric Acid from Cranberry by CCC Followed by prep-HPLC Using Robotic CCC Solvent System Selection

High-performance counter-current chromatography has been used for the separation of delphinidin-3-O-sambubioside, cyanidin-3-O-sambubioside and p-coumaric acid from crude extract of cranberry. The separation was performed with a two-phase solvent system composed of butanol/0.05% aqueous trifluoroacetic acid/methanol at a volume ratio of 4:5:1. The two-phase solvent system was selected following the determination of partition coefficients (K) in a range of solvent systems using a robotic solvent system selection method. Analytical scale CCC confirmed that this phase system separated the components from a crude cranberry extract (40 mg scale) with acceptable purities. Preparative CCC of 400 mg of crude yielded 4.2 mg of p-coumaric acid at a purity of over 98%, 3.6 mg of delphinidin-3-O-sambubioside at a purity of over 97% and 4.5 mg of cyanidin-3-O-sambubioside at a purity of 73%, which was further purified by preparative high-performance liquid chromatography to yield 3 mg cyanidin-3-O-sambubioside at 95% purity. The identification of delphinidin-3-O-sambubioside, cyanidin-3-O-sambubioside and p-coumaric acid was performed by ESI-MS, 1H-NMR and 13C-NMR spectra.     

Isolation and structure determination of a new flavone glycoside from seed residues of seabuckthorn (Hippophae rhamnoides L.)

In this study, a valid method was established for the isolation and purification of flavone glycosides from Hippophae rhamnoides L. seed residues using high-speed counter-current chromatography in one step, with a solvent system of ethyl acetate-methanol-n-butyl alcohol-water (9:1:0.5:9, v/v/v/v). A total of 28.8 mg compound I and 57.3 mg compound II were obtained from 200 mg of flavone H-glycosides rich extract, with purities of 98.3 and 96.4%, respectively. The structures of two compounds were identified by MS and NMR. 3-O-β-D-Sophorosylkaempferol-7-O-{3-O-[2(E)-2,6-dimethyl-6-hydroxyocta-2,7-dienoyl]}-α-L-rhamnoside is compound I and compound II named hippophanone is a new compound were identified by MS and NMR. The method was efficient and convenient, which could be used for the preparative separation of flavone glycosides from H. rhamnoides L. seed residues.     

Electrical Behavior of the Insulator Class-E around Glass Transition: Experimental and Numerical Analyses

Currents flowing through semicrystalline polyethylene terephthalate (PET) film were measured over the temperature range 60°–100°C in electric fields from 24 × 10⁶ to 72 × 10⁶ V/m. A study of the influence of these external stresses on the electrical behavior of PET, at glass transition phase, permitted interpreting its response in terms of dipolar relaxation and movements of free charges. The simulation of the charging current around the glass transition temperature using a model consisting of the presence of bipolar carriers and one kind of permanent dipole with relaxation time τ allowed reproducing the experimental behavior. From this numerical calculation, space dependence of charge densities and field can be determined in order to explain the electrical behavior of current, which depends on parameters such as injection coefficient A _i , relaxation time τ, and mobility μ.     

Rapid quantitative analysis of individual anthocyanin content based on high‐performance liquid chromatography with diode array detection with the pH differential method

A new quantitative technique for the simultaneous quantification of the individual anthocyanins based on the pH differential method and high‐performance liquid chromatography with diode array detection is proposed in this paper. The six individual anthocyanins (cyanidin 3‐glucoside, cyanidin 3‐rutinoside, petunidin 3‐glucoside, petunidin 3‐rutinoside, and malvidin 3‐rutinoside) from mulberry (Morus rubra) and Liriope platyphylla were used for demonstration and validation. The elution of anthocyanins was performed using a C₁₈ column with stepwise gradient elution and individual anthocyanins were identified by high‐performance liquid chromatography with tandem mass spectrometry. Based on the pH differential method, the high‐performance liquid chromatography peak areas of maximum and reference absorption wavelengths of anthocyanin extracts were conducted to quantify individual anthocyanins. The calibration curves for these anthocyanins were linear within the range of 10–5500 mg/L. The correlation coefficients (r²) all exceeded 0.9972, and the limits of detection were in the range of 1–4 mg/L at a signal‐to‐noise ratio ≥5 for these anthocyanins. The proposed quantitative analysis was reproducible with good accuracy of all individual anthocyanins ranging from 96.3 to 104.2% and relative recoveries were in the range 98.4–103.2%. The proposed technique is performed without anthocyanin standards and is a simple, rapid, accurate, and economical method to determine individual anthocyanin contents.     

Nanostructure and dielectric properties of a twist-bend nematic liquid crystal mixture

We present freeze-fracture transmission electron microscopy (FF-TEM), dielectric spectroscopy and electro-optic measurements on a dimeric liquid crystal mixture, which previously was proposed to form the twist-bend nematic (N_tb) phase. Our FF-TEM studies provide a direct image of a 10.5 nm periodic structure, consistent with the expected nanoscale, heliconical twist-bend modulation of the molecular orientation. Dielectric measurements in the 100 Hz to 10 MHz range reveal three nearly Debye-type dispersion processes in the nematic and the twist-bend phase. Low frequency 8 V/µm electric fields applied on planar cells cause the optical-scale stripe texture (another characteristic feature of the N_tb phase) to disappear. Higher (>16 V/µm) fields gradually realign the heliconical axis along the electric field; it relaxes back after the field removal.     

Abeliaside,a new phenolic glucoside from Abelia triflora

A new phenolic glucoside, abeliaside, along with four known compounds, 5,6,7,4′-tetrahydroxy flavones, caffeic acid, 4-O-caffeoylquinic acid and caffeic acid glucoside, was isolated from the leaves of Abelia triflora R. Br. (Caprifoliaceae). The structure of the new compound was elucidated by different spectroscopic techniques. Compounds 1–5 were assayed for their anticancer activities against two cancerous human cell lines, MCF-7 and PC-3 cells, and normal Vero cell line using the crystal violet staining method. From the results it could be seen that caffeic acid possessed the highest anticancer effect against MCF-7 (IC₅₀: 17 μg/mL) and PC-3 (IC₅₀: 20.1 μg/mL) compared to vinblastine sulphate as reference drug (IC₅₀: 4.6, 2.8 μg/mL). The other compounds showed weak anticancer activity on both cell lines.     

Officinalioside,a new lignan glucoside from Borago officinalis L.

A new lignan glucoside, officinalioside (1), was isolated from n-BuOH fraction of the aerial parts of Borago officinalis L., together with four known compounds: actinidioionoside (2), roseoside (3), crotalionoside C (4) and kaempferol 3-O-β-D-galactopyranoside (5). The structure of the new compound was established by means of spectroscopic and chemical analyses. Compounds 1 and 2 showed a moderate DPPH radical scavenging activity (IC₅₀: 52.6 ± 1.70 and 41.3 ± 0.25 μM, respectively) comparable with that of the standard trolox (16.6 ± 2.2 μM) without any significant cytotoxicity towards human cell line A549 (IC₅₀ > 100 μM).     

Antioxidant activities and bioactive compounds of five Jalopeno peppers (Capsicum annuum) cultivars

The present study was designed to evaluate the contents of different antioxidants compounds and their antioxidant activities in Jalopeno peppers (Capsicum annuum) cultivars (El Dorido, Grande, Tula, Sayula and El Rey) extracts. Free radical scavenging activity of Grande was recorded as high as 87% followed by El Dorido (83%). Results of reducing power (Fe³⁺ to Fe²⁺) showed that Grande (0.85%) and El Dorido (0.81%) fruit extract absorbance value were close to synthetic antioxidant BHT (0. 97%) obtained at100 μg/mL. The results showed that total phenolic content of El Dorido and Grande were significantly higher compared to other Jalapeno pepper. Results indicated strong and positive correlation between antioxidant activity and carotenoids content (r = 0.75), vitamin C (r = 0.78) and total capsaicinoids (r = 0.84), respectively. The results of the antioxidant activity assays showed that the El Dorido and Grande had strongest antioxidant activity compared to other peppers cultivars in this study.