scholarly journals The distribution of polyphenols in the tea plant (Camellia sinensis L.)

1969 ◽  
Vol 113 (5) ◽  
pp. 741-755 ◽  
Author(s):  
G. I. Forrest ◽  
D S Bendall
Keyword(s):  
Tea Plant ◽  
Steady Increase ◽  
Protective Layers ◽  
Mature Leaves ◽  
High Concentrations ◽  
Root Apices ◽  
Layer Chromatography ◽  
Derivatives Of ◽  
Ring Hydroxylation

1. Methods for the separation and determination of the polyphenolic components of the tea plant by thin-layer chromatography and colorimetric reactions have been devised. 2. High concentrations of catechins, flavonols and depsides were found to be restricted to the young vegetative and floral shoots, whereas leucoanthocyanins or flavylogens were characteristic of the more bulky axial tissues of the plant. 3. In the young shoots cell growth was correlated with an increasing degree of flavonoid B-ring hydroxylation. 4. Maximal flavylogen concentrations occurred in the outer protective layers of stem and of seed coat. 5. Mature leaves were shown to contain derivatives of the flavones apigenin and luteolin. 6. Developing seedlings showed a steady increase in polyphenol complexity; flavylogens were concentrated at shoot and root apices and accumulated at the stem base. 7. It is postulated that the flavanols (leucoanthocyanins and catechins), because they can co-polymerize, are of use to the plant for protection of wood and bark against infection and decay.

The synthesis, separation, and identification of the methyl ethers of arabinose and their derivatives

1967 ◽  
Vol 45 (3) ◽  
pp. 275-290 ◽  
Author(s):  
S. C. Williams ◽  
J. K. N. Jones
Keyword(s):  
Reducing Sugars ◽  
Reducing Sugar ◽  
The Other ◽  
Partition Chromatography ◽  
Ring Form ◽  
Optical Rotations ◽  
Layer Chromatography ◽  
Derivatives Of ◽  
Spray Reagents

A study has been made of various methods available for the identification and separation of the methyl ethers of arabinose. Gas–liquid partition chromatography has been used to separate the acetylated glycosides and the acetylated alditols of the methyl ethers of arabinose. All of the methyl ethers of arabinopyranose and arabinofuranose have been separated by paper chromatography. Several spray reagents have been used to distinguish between those methyl ethers with similar rates of movement. Thin-layer chromatography has been used to separate the methyl glycosides, acetylated methyl glycosides, and glycitols of the methyl ethers of arabinose, as well as the methyl ethers of the reducing sugar. The optical rotations of the reducing sugars and of the methyl glycosides of the methyl ethers of arabinose provide information about the ring form and, in the case of the glycosides, about the anomer present. The rotations of the acetylated and unacetylated O-methyl arabinitols aid in the determination of the position of the methyl substitutents. In connection with this study, all of the mono-O-methyl and tri-O-methyl, and most of the di-O-methyl ethers of arabinose have been synthesized. New syntheses have been devised for 4-O-methyl and 2,3-di-O-methyl arabinose, and the other sugars have been synthesized by known or partially revised syntheses. During this work, previously unreported derivatives of these sugars have been prepared.

Determination of Matacil and Zectran by Fluorigenic Labeling, Thin Layer Chromatography, and In Situ Fluorimetry

1972 ◽  
Vol 55 (6) ◽  
pp. 1259-1264
Author(s):  
R W Frei ◽  
J F Lawrence
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Sulfonyl Chloride ◽  
Relative Standard ◽  
Dansyl Derivatives ◽  
Layer Chromatography ◽  
Derivatives Of ◽  
Fluorescent Derivatives

Abstract The fluorigenic labeling of Matacil (4-dimethylamino- m-tolyl N-methylcarbamate) and Zectran (4-dimethylamino-3,5-xylyl Wmethylcarbamate) with dansyl chloride (1-dimethylamino- naphthalene-5-sulfonyl chloride) results in 3 fluorescent derivatives, and labeling with NBD-Cl (4-chloro-7-nitrobenzo- 2,1,3-oxadiazole) produces 2 fluorescent derivatives for each carbamate, all of which can be separated by thin layer chromatography (TLC). These derivatives are identified by nuclear magnetic resonance, infrared, and fluorescence spectroscopy, aided by TLC data. The carbamates are hydrolyzed in dilute base and the resulting amine or phenol hydrolysis products react with the labeling reagents. The derivatives are analyzed by TLC and in situ fluorimetry with a spectrophotometer in the fluorescence mode and a spectrophotofluorometer with the thin layer scanning accessory. Reactions, fluorescence phenomena, and chromatographic properties of the derivatives are investigated for evaluation of the method as a quantitative technique. A reproducibility of 3–5% relative standard deviation can be expected in the concentration range from 15 to 300 ng/spot for derivatives of the 2 labeling procedures. The dansyl derivatives are instrumentally detectable as low as 1 ng/spot while the NBD derivatives may be detected at concentrations of less than 0.5 mg/spot.

scholarly journals Alkylresorcinols in rye (Secale cereale L.) grains. I. Micromethod for determination of alkyl derivatives of resorcinol in rye grain

2015 ◽  
Vol 44 (4) ◽  
pp. 479-489 ◽  
Author(s):  
W. Mejbaum-Katzenellenbogen ◽  
F. Tłuścik ◽  
A. Kozubek ◽  
A. Sikorski
Keyword(s):  
Preparative Thin Layer Chromatography ◽  
Uv Spectrum ◽  
Selective Determination ◽  
Alkyl Derivatives ◽  
Secale Cereale L ◽  
Spectrum Characteristic ◽  
Acetone Extracts ◽  
Layer Chromatography ◽  
Derivatives Of

A pure preparation of alkylresorcinol from rye grains was obtained by preparative thin-layer chromatography, which gave a UV spectrum characteristic for 5-n-alkylresorcinols and orcinol. This preparation served as standard in the elaboration of a micro method (for alkylresorcinols determination in acetone extract from rye grain. It was found that this method is suitable for selective determination of 5-n-alkylrezorcinols in acetone extracts from rye grains.

Substances Interfering with the Gas-Liquid Chromatographic Determination of T-2 Mycotoxin

1976 ◽  
Vol 59 (1) ◽  
pp. 221-223
Author(s):  
Chester J Mirocha ◽  
Sadanand V Pathre ◽  
Jerome Behrens
Keyword(s):  
Trimethylsilyl Ether ◽  
Chromatographic Determination ◽  
Cereal Grains ◽  
Feed Mixture ◽  
Animal Fats ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Layer Chromatography ◽  
Derivatives Of

Abstract Two substances interfering with the gas-liquid chromatographic (GLC) detection of the T-2 mycotoxin were identified as 1-glycerylmonooleate and 1-glycerylmonolinoleate. These monoglycerides are natural products formed by species of Fusarium growing on cereal grains and are also additives contained in liquid vegetable and animal fats added to the feed mixture. The monoglycerides can be removed from the analytical sample by resolution by thin layer chromatography prior to separation by GLC. Trimethylsilyl ether derivatives of the monoglycerides and T-2 toxin have almost identical retention times on 3% OV-1 columns, whereas the trifluoroacetyl and pentafluoropropionyl derivatives give baseline separation on the same column. The monoglycerides can be misidentified as the T-2 toxin in analyses involving GLC.

Liquid Chromatographic Determination of Multiresidue Fluorescent Derivatives of Lonophore 1 Compounds, Monensin, Salinomycin, Narasin, and Lasalocid, in Beef Liver Tissue

1986 ◽  
Vol 69 (4) ◽  
pp. 637-641 ◽  
Author(s):  
Elizabeth E Martinez ◽  
Wilbert Shimoda
Keyword(s):  
Liver Tissue ◽  
Chromatographic Determination ◽  
Fluorometric Detection ◽  
Fluorescence Detector ◽  
Beef Liver ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Layer Chromatography ◽  
Derivatives Of

Abstract A liquid chromatographic (LC) method with fluorometric detection was developed to quantitatively determine residue levels of monensin, salinomycin, narasin, and lasalocid in beef liver tissue. The ionophores are extracted from the tissue, purified by both alumina and Sephadex LH-20 column chromatography, and then derivatized. Lasalocid was directly esterified with 9-anthryIdiazomethane (ADAM), but monensin, salinomycin, and narasin were first acetylated with acetic anhydride and then esterified with ADAM. The ADAM derivatives were purified on a silica gel column and separated by LC using an RP C-8 5 μm column. A fluorescence detector set at 365 nm (excitation) and 418 nm (emission) was used to monitor the column effluent. The detection limits were 0.15 ppm, and the calibration curves were linear between 0.5 and 5.0 ppm for all 4 ionophores. Mean recoveries were 57, 70, 75, and 90% for lasalocid (5 ppm), monensin (2.5 ppm), salinomycin (2.5 ppm), and narasin (2.5 ppm), respectively. The ionophores were also separated and semiquantitated by using bioautography and thin layer chromatography with a vanillin spray.

The determination of 4-substituted derivatives of N-nitroso-N-methyl aniline by fast scan differential pulse voltammetry at a hanging mercury drop electrode

1991 ◽  
Vol 56 (12) ◽  
pp. 2815-2826 ◽  
Author(s):  
Jiří Barek ◽  
Viktor Mejstřík ◽  
Ivana Švagrová ◽  
Jiří Zima
Keyword(s):  
Differential Pulse Voltammetry ◽  
Differential Pulse ◽  
Test Sample ◽  
Nitroso Compounds ◽  
Hanging Mercury Drop Electrode ◽  
Mercury Drop Electrode ◽  
Pulse Voltammetry ◽  
Layer Chromatography ◽  
Derivatives Of

Optimum conditions were found for the determination of N-nitroso-N-methyl aniline and its derivatives substituted in the 4 position by -CH3, -OCH3, -Cl, -CN, -OH or -NO2 groups by fast scan differential pulse voltammetry at a hanging mercury drop electrode in the concentration range 1 10-5-2 10-7 mol l-1. It was demonstrated that these techniques are useful for the analysis of a mixture of the test substances either directly or after separation by thin-layer chromatography and that false positive results can be eliminated by UV irradiation of the test sample. An attempt to further increase the sensitivity by adsorptive accumulation of the test substances on the surface of the hanging mercury drop electrode was not successful as the test N-nitroso compounds are practically not adsorbed on this electrode.

scholarly journals Studies on the polyphenol metabolism of tissue cultures derived from the tea plant (Camellia sinensis L.)

1969 ◽  
Vol 113 (5) ◽  
pp. 765-772 ◽  
Author(s):  
G. I. Forrest
Keyword(s):  
Growth Rate ◽  
Callus Tissue ◽  
High Light Intensity ◽  
Tea Plant ◽  
Anthocyanin Synthesis ◽  
Polyphenol Oxidase Activity ◽  
Intact Plants ◽  
Liquid Suspension ◽  
High Concentrations ◽  
Root Apices

1. The growth characteristics on various media of solid and liquid suspension cultures derived from the stem of the tea plant are described; chlorophyll and anthocyanin synthesis occurred in the light. 2. Only the simplest catechins and leucoanthocyanins were present in callus tissue, although oligomeric and polymeric leucoanthocyanin fractions were also represented. Light caused an increase in all monomeric components analysed, but inhibited polymerization of the leucoanthocyanins. 3. The polyphenol oxidase activity of cultures was comparable with that of the apical regions of the intact plant, and was inversely correlated with growth rate. 4. Growth was stimulated by hormonal variation, and inhibited by high concentrations of sucrose and by high light-intensity; polyphenol concentrations were generally inversely correlated with growth rate. 5. From the inability of callus tissue and of cultured root apices to synthesize complex catechins, it is inferred that complex catechin formation in intact plants is associated with the process of cell vacuolation.

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