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Articles 2311 - 2340 of 2730
Full-Text Articles in Physical Sciences and Mathematics
Aspertins A-D: Further Piperidine Alkaloids From Andrachne Aspera} (Euphorbiaceae), Viqar Uddin Ahmad, Arshad Kamal, Muhammad Shaiq Ali
Aspertins A-D: Further Piperidine Alkaloids From Andrachne Aspera} (Euphorbiaceae), Viqar Uddin Ahmad, Arshad Kamal, Muhammad Shaiq Ali
Turkish Journal of Chemistry
The aerial parts of Andrachne aspera belonging to the family Euphorbiaceae yielded four new piperidine alkaloids: aspertin-A (1), aspertin-B (2), aspertin-C (3) and aspertin-D (4). The structures of isolated alkaloids were elucidated by NMR, mass spectrometery and chemical means.
Diels-Alder Reactions Using 5 M Liclo_{4} -Diethyl Ether Catalyst, Mesut Kacan, H. R. Ferhat Karabulut
Diels-Alder Reactions Using 5 M Liclo_{4} -Diethyl Ether Catalyst, Mesut Kacan, H. R. Ferhat Karabulut
Turkish Journal of Chemistry
The rate acceleration of Diels-Alder reactions in 5.0 M lithium perchlorate-diethyl ether was re-examined using itaconic anhydride and itaconic acid. Rate acceleration was observed for non-functionalised dienes, but functionalised dienes gave the starting or polymeric materials.
Synthesis Of 2'-Deoxy-2'-Fluoro-L-Arabinofuranosyl Imidazole Derivatives, Süreyya Ölgen
Synthesis Of 2'-Deoxy-2'-Fluoro-L-Arabinofuranosyl Imidazole Derivatives, Süreyya Ölgen
Turkish Journal of Chemistry
A new series of imidazole nucleosides was synthesized via direct condensation and construction of heterocyclic moiety from glycosyl amine templates. The characterization of the compounds was accomplished by elemental analysis, ^{1}H-NMR, ^{13}C-NMR, IR, UV-VIS spectral data and optical rotation.
Determination Of Zinc In Aerosol Samples By Discrete Nebulization Flame Atomic Absorption Spectrometry, Deni̇z Yurtsever Sarica, Di̇lek Akim, Tuncel Özden
Determination Of Zinc In Aerosol Samples By Discrete Nebulization Flame Atomic Absorption Spectrometry, Deni̇z Yurtsever Sarica, Di̇lek Akim, Tuncel Özden
Turkish Journal of Chemistry
A well-known analytical method, ``discrete nebulization'', which is suitable for samples having a limited amount like body fluids, high solid content or salt solutions, and less volatile metals, has been further developed for zinc determination in aerosol samples. The effects of injection volume and nebulizer aspiration rate on absorbance and precision were studied. A calibration graph was obtained linearly up to 1.75 mg/L Zn with a 0.9988 correlation coefficient and 3.09\% RSD using 50 \mu L injection volume, values comparable to conventional continuous nebulization. The detection limit (3S) achieved by the method was calculated to be 1.09 ng or 0.020 …
Determination Of Trace Elements In Iron Minerals By Atomic Absorption Spectrometry, Trajce Stafilov, Dragica Zendelovska
Determination Of Trace Elements In Iron Minerals By Atomic Absorption Spectrometry, Trajce Stafilov, Dragica Zendelovska
Turkish Journal of Chemistry
A method for the determination of lead, cobalt, nickel, chromium, zinc and manganese in iron minerals siderite (FeCO_3), hematite (Fe_{2}O_{3), pyrite and marcasite (FeS_{2) by flame and Zeeman electrothermal atomic absorption spectrometry (ETAAS) was developed. Interferences were investigated by measuring the absorbance of the elements investigated in series of samples with varying mass ratios of the elements investigated and iron as the potential interfering element. It was found that there was no interference in the determined mass ratios of iron on the absorbance of Mn and Zn and that they could be directly analyzed by flame and electrothermal atomic absorption …
A Comparative Study For Basic Characterization Of Three Clinoptilolite Specimens, Eva Chmielewska, Eva Samajova, Jan Kozac
A Comparative Study For Basic Characterization Of Three Clinoptilolite Specimens, Eva Chmielewska, Eva Samajova, Jan Kozac
Turkish Journal of Chemistry
Physicochemical and mineralogical characteristics of the clinoptilolite tuffs of Chinese, Slovakian and American origin were investigated using various techniques, i.e. X - ray powder diffraction, water vapour desorption, ion exchange and chemical analysis.
Effects Of Ozonation On Characteristics Of Aquatic Fulvic Acid, Şermi̇n Gül
Effects Of Ozonation On Characteristics Of Aquatic Fulvic Acid, Şermi̇n Gül
Turkish Journal of Chemistry
Aquatic fulvic acid (FA) treated with ozone was characterized by physical/chemical (dissolved organic carbon-DOC), spectroscopic (UV/VIS, IR, fluorescence), chromatographic (gel permeation chromatography-GPC) methods. The influence of ozonation on the subsequent water treatment process such as flocculation and chlorination was also examined. The DOC concentration of the 20 min ozonated FA samples was reduced only a small amount (5%) whereas the UV absorption reduced to a higher percent (40%). The IR spectra of ozonated samples showed a moderate attenuation of the double band and aromatic character of FA. Ozonation of the FA caused the fluorescence intensities to increase steadily with ozonation …
Derivative Spectrophotometric Determination Of Caffeine In Some Beverages, Güzi̇n Alpdoğan, Kadi̇r Karabi̇na, Sidika Sungur
Derivative Spectrophotometric Determination Of Caffeine In Some Beverages, Güzi̇n Alpdoğan, Kadi̇r Karabi̇na, Sidika Sungur
Turkish Journal of Chemistry
Caffeine content was determined in cola, coffee and tea by second and third order derivative spectrophotometry without using any separation or background correction technique and reagent. The method is based on the measurement of the distances between two extremum values (peak to peak amplitudes) in the second order (cola) and third order (coffee and tea) derivative spectra of the sample solution. Calibration curves were constructed for the 2.0-10.0 \mu g ml^{-1}concentration range. As a reference method, reversed phase high performance liquid chromatographic procedure was developed. Commercially available beverages were analyzed by the two methods and the results were statistically compared …
A Semi-Empirical Study On Metal Ion/Murexide Complexation, N. Zeynep Atay, Tereza Varnali
A Semi-Empirical Study On Metal Ion/Murexide Complexation, N. Zeynep Atay, Tereza Varnali
Turkish Journal of Chemistry
Modeling of the metal ion/ligand complexation reactions between divalent metal cations (M^{2 +} ) and hydrophilic tridentate ligand murexide (Mu^{-} ) in water, water+glycerol, and in glycerol was carried out. Kinetic studies showed that the rate of the reaction is very dependent on the metal ion, with Zn^{2 +} > Ni^{2 +} , but, reactions are slower in dispersed glycerol than in dispersed water. Theoretical calculations, which have shown a metal ion dependence, were consistent with the experimental observations. The entropy values calculated in all solvents were negative and were similar in value, indicating that these spontaneous reactions are enthalpy driven.
Stabilization Of Papain By Modification With Chitosan, Ali̇ Kilinç, Seçi̇l Önal, Azmi̇ Telefoncu
Stabilization Of Papain By Modification With Chitosan, Ali̇ Kilinç, Seçi̇l Önal, Azmi̇ Telefoncu
Turkish Journal of Chemistry
Papain (EC 3.4.22.2) was immobilized on chitosan by adsorption and subsequent cross-linking with glutaraldehyde. The immobilized papain displayed a lower specific activity than did the native enzyme. The thermal stability of the immobilized papain, relative to that of the free enzyme, was markedly increased. The storage stability of the conjugated enzyme was enhanced such that more than 85% of the initial activity remained after a month storage at 45°C. The optimum pH of immobilized papain was shifted to the acidic region and enzyme stability was increased at pH levels below 3.5.
Steric Effects On The Oxidation Potential Of 1-Aryl Thioglycosides, Mehmet A. Oturan, Maurice Medebielle, Shirish A. Patil, Robert S. Klein
Steric Effects On The Oxidation Potential Of 1-Aryl Thioglycosides, Mehmet A. Oturan, Maurice Medebielle, Shirish A. Patil, Robert S. Klein
Turkish Journal of Chemistry
The electrochemical oxidation of several 1-arylthioglycosides has been studied by cyclic voltammetry in acetonitrile. We found that the oxidation potential of the \alpha anomer always occurs at a less positive oxidation potential than of the \beta anomer. The difference in the oxidation potential depends on the substituent attached on the C-3 of the sugar moiety and is greatly influenced by the stability of the radical cation obtained after the first electron transfer.
Ft-Ir And Ft-Raman Studies On 3-Aminophthalhydrazide And N-Aminophthalimide, N. Puviarasan, V. Arjunan, S. Mohan
Ft-Ir And Ft-Raman Studies On 3-Aminophthalhydrazide And N-Aminophthalimide, N. Puviarasan, V. Arjunan, S. Mohan
Turkish Journal of Chemistry
The FT-infrared (400-4000 cm^{-1} ) and FT-Raman (100-3500 cm^{-1} ) spectra of N-aminophthalimide and 3-aminophthalhydrazide were recorded. The observed frequencies were assigned to various modes of vibrations on the basis of normal coordinate analysis, assuming C_{S} point group symmetry. The potential energy distribution associated with normal modes is also reported. The assignments of fundamental vibrations agree well with the calculated frequencies.
Application Of Quantitative Structure-Retention Relationships (Qsrr) To A Set Of Organic Bromo And Nitrile Derivatives, Gustavo P. Romanelli, Juan Carlos Autino, Eduardo A. Castro
Application Of Quantitative Structure-Retention Relationships (Qsrr) To A Set Of Organic Bromo And Nitrile Derivatives, Gustavo P. Romanelli, Juan Carlos Autino, Eduardo A. Castro
Turkish Journal of Chemistry
The retention times are studied for two sets of 1-bromo-2-aryiloxyetanes and 3- aryloxypropiononitriles derivatives by means of Quantitative Structure-Retention Relationships (QSRR}). Five quantum mechanical molecular descriptors are used to calculate the regression equations. The fitting polynomials are computed in several-variable at first, second, and third order equations. Results are only significant when resorting to several-variable formulae which seems to point out the rather complex physical chemistry nature of the property under study.
Flow Injection Extraction - Spectrophotometric Determination Of Bismuth With Di-(Hydrogenated Tallow Alkyl) Dimethylammonium Chloride, S. A. Barakat
Flow Injection Extraction - Spectrophotometric Determination Of Bismuth With Di-(Hydrogenated Tallow Alkyl) Dimethylammonium Chloride, S. A. Barakat
Turkish Journal of Chemistry
Bismuth(III) (0-25 \mu g/ml) is determined spectrophotometricaly at 513 nm after extraction into dichloromethane of the ion associate di-(hydrogenatedtallowalkyl)dimethylammonium tetraiodobismuthate. The reagent stream is distilled water, merged with 1.0 M sulfuric acid, 5% potassium iodide and 5% (w/v) ascorbic acid solution. The reagent stream is 0.2% (w/v) di-(hydrogenatedtallowalkyl)dimethylammonium chloride solution. The injection rate is 15 h^{-1}. The calibration graph is linear up to 25 \mu g/ml. The detection limit is 0.35 \mu g/ml Bi. The system is applied on water samples and copper-based alloys.
Spectrophotometric Studies Of The Behavior Of P-Amino-N, N-Dimethyl Aniline With Ferric Nitrate In Methanol, Ali Hassoon Al-Taiar, Suhad K. Shubber, A. Megherbi
Spectrophotometric Studies Of The Behavior Of P-Amino-N, N-Dimethyl Aniline With Ferric Nitrate In Methanol, Ali Hassoon Al-Taiar, Suhad K. Shubber, A. Megherbi
Turkish Journal of Chemistry
The UV-visible absorption bands of the new complex were obtained using p-amino-N, N-dimethyl aniline as an electron donor with ferric nitrate as an electron acceptor in methanol at 25°C. The values of association constant K^{AD}, molar extinction coefficient \varepsilon^{AD}, and absorption band energy of charge transfer complex h \varepsilon_{CT} were calculated. The ionization potential of the donor I^{D}, was calculated from the complex band energy. The kinetics of the above association reaction were studied. This reaction was found to be a first order. The values of the rate constant of the forward reaction k_{1}, the rate constant of the reverse …
A Study Of The Adsorption Of Phenol By Activated Carbon From Aqueous Solutions, Riaz Qadeer, Abdul Hameed Rehan
A Study Of The Adsorption Of Phenol By Activated Carbon From Aqueous Solutions, Riaz Qadeer, Abdul Hameed Rehan
Turkish Journal of Chemistry
A commercial active carbon was tested as an adsorbent for the removal of phenol from aqueous solutions. The optimum conditions for maximum adsorption in terms of shaking time, amount of the adsorbent, and concentration of the adsorbate were identified. The adsorption data fitted the Langmuir isotherm equation in the whole range of concentrations studied. The adsorption of picric acid, pyrogallol and salicylic acid at selected conditions for phenol was also studied. Elution studies to recover the adsorbed phenol from active carbon were performed with distilled water, NaOH and HCl solutions.
An Indirect Lectin Affinity Bioassay For Uromodulin, Zeki̇ Topcu
An Indirect Lectin Affinity Bioassay For Uromodulin, Zeki̇ Topcu
Turkish Journal of Chemistry
Uromodulin is a monomeric glycoprotein excreted in large amounts in urine. Most of the assay methods for quantifying uromodulin rely on the availability of antibodies to this glycoprotein. This study reports a new bioassay for uromodulin without requiring the presence of antibodies. The bioassay is based on the lectin affinity of the glycoprotein and the known interaction between uromodulin and the tumor necrosis factor. The measuring range of the bioassay described in this paper is between 0.13 and 1.25 \mu g/ml, which makes it a potential method for clinical use.
Efficient Synthesis Of 1-Alkoxycarbonyl-Methyl-2-Alkylpyrroles From Dichloro- And Methoxychloropropylalkyl Ketones, Raik A. Gadzhili, Raya A. Nadzhafova, Özge Şeşenoğlu
Efficient Synthesis Of 1-Alkoxycarbonyl-Methyl-2-Alkylpyrroles From Dichloro- And Methoxychloropropylalkyl Ketones, Raik A. Gadzhili, Raya A. Nadzhafova, Özge Şeşenoğlu
Turkish Journal of Chemistry
The condensation reaction of 2,3-dichloropropyl- and 2-methoxy-3-chloropropyl alkyl ketones with alkyl 2-aminoacetate salts leads to 1-alkoxy-carbonylmethyl-2-alkylpyrroles. These compounds, with various bases, gave 1-carbamoylmethyl-, 1-dialkylaminocarbonylmethyl-, 1-carbazoyl methyl-2-alkylpyrroles and potassium salt of 2-alkyl-pyrrolyl-1-acetic acid.
Determination Of Ternary Mixtures Of Vitamins (B_{1}, B_{6}, B_{12}) By Zero-Crossing Derivative Spectrophotometry, Mahmure Üstün Özgür, İkbal Koyuncu
Determination Of Ternary Mixtures Of Vitamins (B_{1}, B_{6}, B_{12}) By Zero-Crossing Derivative Spectrophotometry, Mahmure Üstün Özgür, İkbal Koyuncu
Turkish Journal of Chemistry
A new method for determining ternary mixtures of vitamin B_{1}, B_{6} and B_{12} using second derivative spectrophotometry is described. The procedure is accurate, nondestructive and does not require any separation step or the solving of equations. Calibration graphs were linear up to 20 \mu gml^{-1} of vitamin B_{1} at 228.9 nm (r=0.9999), vitamin B_{6} at 309.6 nm (r=0.9999) and vitamin B_{12} at 361.7 nm (r=0.9998). The method was successfully applied for analyzing synthetic mixtures and commercial pharmaceutical preparations.
Alteration Of Three Turkish Bentonites By Treatment With Na_{2}Co}_{3} And H}_{2}So}_{4}, Nuray Yildiz, Ayla Çalimli
Alteration Of Three Turkish Bentonites By Treatment With Na_{2}Co}_{3} And H}_{2}So}_{4}, Nuray Yildiz, Ayla Çalimli
Turkish Journal of Chemistry
In this study, fine fractions of bentonites from the Çankırı and Kütahya regions were treated with Na_{2}CO_{3} and H_{2}SO_{4}. The resulting materials were analysed by X-ray diffraction (XRD), thermogravimetric and differential thermal analyses (TGA, DTA) and infrared (IR) spectroscopy. Surface areas of the samples were also measured. The results showed that structural changes were observed by treatment with Na_{2}CO_{3} and H_{2}SO_{4}. These changes showed differences depending on exchangeable cations, clay type and the ratio of additives.
The Effects Of Benzoic Acid In Chloride Solutions On The Corrosion Of Iron And Aluminum, Si̇bel Zor
The Effects Of Benzoic Acid In Chloride Solutions On The Corrosion Of Iron And Aluminum, Si̇bel Zor
Turkish Journal of Chemistry
In this work, the corrosion behavior of iron and aluminum was investigated in 0.1 M NaCl solutions with an initial pH value of 8 and containing various concentrations (0, 30, 150, 300 ppm) of benzoic acid. For this purpose, the anodic and cathodic semilogarithmic current-potential curves, weight loss and pH of the solution were determined over time. The changes in the concentrations of benzoic acid in the solutions with time were determined by a UV spectrophotometer. According to the results obtained in this investigation, benzoic acid in 0.1 M NaCl acts on iron and aluminum as an inhibitor. This effect …
The Effect Of Acid Activation On Some Physicochemical Properties Of A Bentonite, Müşerref Önal, Yüksel Sarikaya, Tülay Alemdaroğlu, İhsan Bozdoğan
The Effect Of Acid Activation On Some Physicochemical Properties Of A Bentonite, Müşerref Önal, Yüksel Sarikaya, Tülay Alemdaroğlu, İhsan Bozdoğan
Turkish Journal of Chemistry
A white calcium bentonite (CaB) from the K\"{u}tahya region/Turkey was activated by heating it for 6 hours at 97°C in H_{2}SO_{4} solution. The mass percentage of H_{2}SO_{4} in the bentonite-acid mixture was varied from 0 to 70%. The chemical analysis (CA), cation exchange capacity (CEC), differential thermal analysis (DTA) curves and X-ray diffraction (XRD) patterns of the prepared samples were determined. The specific surface area (A) and the specific micropore-mesopore volume (V) were calculated respectively from the adsorption and desorption data of N_{2} obtained at liquid N_{2} temperature. How the calcium montmorillonite (CaM) layers in the CaB were decomposed during …
Production Of Mesophase Pitch From Coal Tar And Petroleum Pitches Using Supercritical Fluid Extraction, Mustafa Zafer Özel, Keith D. Bartle
Production Of Mesophase Pitch From Coal Tar And Petroleum Pitches Using Supercritical Fluid Extraction, Mustafa Zafer Özel, Keith D. Bartle
Turkish Journal of Chemistry
Supercritical fluid extraction (SFE) is currently being investigated as a possible technique in the production of high quality mesophase pitch from coal tar and petroleum pitches. Mesophase pitch is used to make high technology products, such as carbon fibre. The conventional production of mesophase pitch initially involves the removal of low molecular weight species from coal tar and petroleum pitches. The remaining residue is then transformed into a mesophase pitch through a polymerisation process. The aim of this study involves the extraction of light molecular weight species using SFE. Both petroleum and coal tar pitch contain complex aromatic molecules with …
Simultaneous Determination Of Fe(Ii) And Fe(Iii) In Pharmaceutical Samples By Post-Column Derivatization/Hplc, Hami̇de Z. Şenyuva, Deni̇z Yurtsever Sarica, Tuncel Özden
Simultaneous Determination Of Fe(Ii) And Fe(Iii) In Pharmaceutical Samples By Post-Column Derivatization/Hplc, Hami̇de Z. Şenyuva, Deni̇z Yurtsever Sarica, Tuncel Özden
Turkish Journal of Chemistry
A post-column derivatization HPLC method with visible absorbance detection at 521 nm was modified for the simultaneous determination of Fe(II) and Fe(III) in mixtures. The method was applied to pharmaceuticals marketed in Turkey. Iron species were separated on a post-column derivatization HPLC, IonPac CS5A (4x250 mm) analytical column using a pyridine-2,6-dicarboxylic acid based eluent. The determinations of Fe(II) and Fe(III) were also realized by the most common method of FAAS, total iron determination. Detection limits (3S) were found to be 0.109 \mu g/L for Fe(II) and 0.217 \mu g/L for Fe(III), respectively. The mean recovery of the HPLC and AAS …
Chemical Exfoliation Characteristics Of Karakoç Phlogopite In Hydrogen Peroxide Solution, Erol Üçgül, İsmai̇l Gi̇rgi̇n
Chemical Exfoliation Characteristics Of Karakoç Phlogopite In Hydrogen Peroxide Solution, Erol Üçgül, İsmai̇l Gi̇rgi̇n
Turkish Journal of Chemistry
The chemical exfoliation characteristics of phlogopite samples taken from Sivas - Yıldızeli-Karakoç (Turkey) ore were investigated. H_{2}SO_{4}, HCl, HNO_{3}, H_{3}PO_{4} and H_{2}O_{2} solutions at varying concentrations were tested for chemical exfoliation and the best reagent for this purpose was determined to be hydrogen peroxide. In the exfoliation tests performed, hydrogen peroxide concentration, temperature and reaction time were observed to be important parameters, with solid/liquid ratio being of minor importance. The exfoliation characteristics of the material increased with increases in hydrogen peroxide concentration and depending on the reaction time (1-30 hours) a maximum value of a 49-fold increase in swelling was …
Cadmium And Mercury Uptake By Immobilized Pleurotus Sapidus, Yağmur Yalçinkaya, M. Yakup Arica, Levent Soysal, Adi̇l Deni̇zli̇, Ömer Genç, Sema Bektaş
Cadmium And Mercury Uptake By Immobilized Pleurotus Sapidus, Yağmur Yalçinkaya, M. Yakup Arica, Levent Soysal, Adi̇l Deni̇zli̇, Ömer Genç, Sema Bektaş
Turkish Journal of Chemistry
Pleurotus sapidus} basidiospores immobilized onto Ca-alginate beads were used for the removal of cadmium and mercury ions from aqueous solutions. The biosorption of Cd(II) and Hg(II) ions on the alginate beads and both immobilized live and heat inactivated fungal mycelia of Pleurotus sapidus} was studied from aqueous solutions in the concentration range of 30-500 mg L^{ - 1}. The biosorption of Cd(II) and Hg(II) ions by the alginate and both live and heat inactivated immobilized preparations increased as the initial concentration of the ions increased in the medium. Maximum biosorption capacity for immobilized live and heat inactivated fungal mycelia of …
Phytochemical Studies At The Bulbs Of Ornithogalum Umbellatum L., Temi̇ne Şabudak, Ülkü Oyman
Phytochemical Studies At The Bulbs Of Ornithogalum Umbellatum L., Temi̇ne Şabudak, Ülkü Oyman
Turkish Journal of Chemistry
Phytochemical examination of the bulbs of Ornithogalum umbellatum L. led to the isolation a new steroidal compound. Its structure was determined to be 3-O-(2'-methoxy-4'-(2-pentenal))-phenyl sitosterol (1) by spectroscopic data and chemical evidence.
Terpenoids And Aromatic Compounds From Euphorbia Heteradena, Sevi̇l Öksüz, Ayhan Ulubelen, Asli Barla, Wolfgang Voelter
Terpenoids And Aromatic Compounds From Euphorbia Heteradena, Sevi̇l Öksüz, Ayhan Ulubelen, Asli Barla, Wolfgang Voelter
Turkish Journal of Chemistry
Euphorbia heteradena Jaub. & Spach (Euphorbiaceae), a plant endemic to Turkey, has not been investigated previously. The CH_{2}Cl_{2} extract of the aerial parts of Euphorbia heteradena yielded 24-methylenecycloartanol, cycloart-25-en-3\beta ,24-diol, cycloart-22-en-3\beta ,25-diol, vomifoliol, vomifoliol 9-O-\beta -D-glucopyranoside, 3,4,3'-tri-O-methoxy ellagic acid, syringic acid and scopoletin. The structures of the isolates were identified by high field spectroscopic methods including 1D and 2D NMR techniques.
Phenylethanoid Glycosides From Scutellaria Galericulata, Tayfun Ersöz, Deni̇z Taşdemi̇r, İhsan Çaliş, Chris M. Ireland
Phenylethanoid Glycosides From Scutellaria Galericulata, Tayfun Ersöz, Deni̇z Taşdemi̇r, İhsan Çaliş, Chris M. Ireland
Turkish Journal of Chemistry
From the aerial parts of Scutellaria galericulata L., four phenylethanoid glycosides, 2-(4-hydroxyphenyl)-ethyl-(6-O-caffeoyl)-\beta -D-glucopyranoside (1), calceolarioside B (2), osmanthuside E (3) and martynoside (4), were isolated. The structure elucidations of the isolated compounds were performed by spectroscopic (UV, IR, ESI-MS, 1D- and 2D-NMR) methods. Compounds 1-4 demonstrated scavenging properties toward the 1,1-diphenyl-1-picrylhydrazyl (DPPH) radical in TLC autographic assays.
Comparison Of Supercritical Fluid And Solvent Extraction Of Feverfew (Tanacetum Parthenium), Muammer Kaplan, Mark R. Simmonds, George Davidson
Comparison Of Supercritical Fluid And Solvent Extraction Of Feverfew (Tanacetum Parthenium), Muammer Kaplan, Mark R. Simmonds, George Davidson
Turkish Journal of Chemistry
High performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) analyses are used to show that supercritical fluid extraction (SFE) using carbon dioxide is an effective means of extracting a range of components from feverfew samples. It was found that the specific compositions of solvent extracts and SFE extracts are different. The amounts of the presumed active ingredient parthenolide have been confirmed to be very variable. Feverfew seeds were particularly rich in parthenolide, while dried powdered samples contained less and, in one case, none at all. The tunability of SFE has been demonstrated, and it was shown that successive extractions …