A Qualitative Gas Chromatographic Analysis of Substituted 5,6-Dihydroxyindoles from the Urine of Patients with Melanoma

1981 ◽  
Vol 67 (4) ◽  
pp. 325-332 ◽  
Author(s):  
Stanislav Pavel ◽  
Frits A. J. Muskiet ◽  
Alena Budešínská ◽  
Jirí Duchon
Keyword(s):  
Ethyl Acetate ◽  
Chromatographic Analysis ◽  
Helix Pomatia ◽  
Nitrogen Atmosphere ◽  
Spectrometric Analysis ◽  
Gas Chromatographic Analysis ◽  
Indolic Compounds ◽  
Hydrolysis Of ◽  
Ethyl Acetate Extracts ◽  
Chromatographic Mass

A qualitative gas chromatographic analysis of trimethylsilylated ethyl acetate extracts of melanotic urine revealed 5 indolic compounds, which have been identified as substituted 5,6-dihydroxyindoles. Ethyl acetate extracts of melanotic urines at pH 2.0 contained isomeric 5-hydroxy-6-methoxy and 6-hydroxy-5-methoxy-indolyl-2-carboxylic acids which were not separable under the conditions used. A careful hydrolysis of melanotic urine with a Helix pomatia preparation followed by extraction at pH 6.5 in a nitrogen atmosphere released 3 additional indolic compounds from their conjugated form. Using gas chromatographic-mass spectrometric analysis they were identified as 5-hydroxy-6-methoxy, 6-hydroxy-5-methoxyindole and 5,6-dihydroxyindole.

scholarly journals Daidzein and genistein concentrations in human milk after soy consumption

1996 ◽  
Vol 42 (6) ◽  
pp. 955-964 ◽  
Author(s):  
A A Franke ◽  
L J Custer
Keyword(s):  
Human Milk ◽  
Ethyl Acetate ◽  
Electrochemical Detection ◽  
Newborn Infants ◽  
Hplc Method ◽  
Soy Isoflavones ◽  
Spectrometric Analysis ◽  
Diode Array ◽  
Array Detection ◽  
Hydrolysis Of

Abstract Soy isoflavones were quantified from human milk by a fast, precise, and selective HPLC method after enzymatic hydrolysis of conjugated isoflavones and extraction with ethyl acetate. Isoflavone aglycones and their mammalian metabolites equol and O-desmethylangolensin were separated selectively and identified by absorbance patterns, fluorometric and electrochemical detection, gas chromatography-mass spectrometric analysis after trimethylsilylation, and with internal and external authentic standards. HPLC injections of 20 microL of human milk showed detection limits of 1-3 pmol for all analytes by using diode-array detection. The detection limit could be improved by as much as 1000-fold by extended concentration through partitioning with ethyl acetate, by using electrochemical detection, by increasing the injection volumes, or by combining these techniques. We used the proposed method to monitor isoflavone concentrations in human milk and in human urine after challenge with 5, 10, and 20 g of roasted soybeans in the diet. Implications of the results for the potential of isoflavones to prevent cancer in newborn infants exposed to these agents are discussed.

Chemical studies on oils derived from aspen poplar wood, cellulose, and an isolated aspen poplar lignin

1983 ◽  
Vol 61 (9) ◽  
pp. 2010-2015 ◽  
Author(s):  
Richard L. Eager ◽  
James M. Pepper ◽  
Jiben C. Roy ◽  
Joseph F. Mathews
Keyword(s):  
Molecular Weight ◽  
Relative Abundance ◽  
Chromatographic Analysis ◽  
Initial Study ◽  
Poplar Wood ◽  
Substituted Phenols ◽  
Wood Cellulose ◽  
Gas Chromatographic Analysis ◽  
Chemical Studies ◽  
Chromatographic Mass

An initial study has been made of the chemical nature of the oil phase resulting from the the conversion of aspen poplar wood, cellulose, and an isolated lignin from the aspen poplar as a result of their interactions with water and carbon monoxide in the presence of sodium carbonate at 360 °C. Gas chromatographic analysis of the sodium hydroxide soluble fractions from each substrate revealed similar spectra of alkyl-substituted phenols. The relative abundance of identified low molecular weight phenolic compounds decreased from lignin to wood to cellulose. This was in agreement with the known phenolic nature of lignin. As well, it confirmed the synthesis during reaction of such compounds from a carbohydrate substrate. Gas chromatographic analysis of the whole oils also revealed the presence in each case of several alkyl-substituted cyclopentanones whose relative abundance decreased from cellulose to wood to lignin. Silica gel column separation of the oils, after a charcoal treatment, followed by capillary gas chromatographic – mass spectrometric analyses of the resulting fractions indicated the presence of other higher molecular weight phenols, napthols, cycloalkanols, cycloalkanones, and polycyclic and long chain alkanes and alkenes.

scholarly journals Uji Aktivitas Sitotoksik dan Antibakteri Ekstrak Daun Tumbuhan Rengas (Gluta renghas L)

2020 ◽  
Vol 11 (1) ◽  
pp. 52-60
Author(s):  
Sanusi Ibrahim ◽  
Suryati Suryati ◽  
Enda Desriansyah Aziz
Keyword(s):  
Antibacterial Activity ◽  
Ethyl Acetate ◽  
Methanol Extract ◽  
Ethyl Acetate Extract ◽  
Inhibition Zone ◽  
Cytotoxicity Activity ◽  
E Coli ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Ethyl Acetate Extracts

Generally, Gluta renghas L. is known because of its very toxic latex which can cause hard irritations to skin. Although, rengas latex has efficacy as an antibacterial agent. Related to previous research, it has been reported that there are urisol, rengol, glutarengol, laccol, and thitsiol in rengas latex. The woody trunk was reported to contain flavonoid, benzenoid, lipid, and steroid compounds. The leaves, were reported shows that the leaves of G. renghas contain an anticholinesterase substance and can be reduced the rate of hydrolysis of acetylcholine. Extraction of rengas leaves has been carried out. It has been shown phenols, steroids, and coumarins compounds in methanol extract, flavonoids, phenols, saponins and alkaloids compounds in ethyl acetate extract, steroids and alkaloids compounds in hexane extract. In the present, cytotoxicity and antibacterial activity have been tested. The results show that the great cytotoxicity activity by ethyl acetate extracts which have an LC50 value is 123,718 µg/mL (R2 0.9822), while the great antibacterial activity shown by methanol extract 1,000 µg/mL with a diameter of inhibition zone 19.02 mm (S. aureus) and 16.06 mm (E. coli). 

Liquid Chromatographic Method for Determination of Patulin in Apple Juice

1974 ◽  
Vol 57 (5) ◽  
pp. 1111-1113 ◽  
Author(s):  
George M Ware ◽  
Charles W Thorpe ◽  
Albert E Pohland
Keyword(s):  
Ethyl Acetate ◽  
Apple Juice ◽  
Spectrometric Analysis ◽  
Liquid Chromatograph ◽  
Ultraviolet Detector ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic ◽  
Acetate Derivative ◽  
Chromatographic Mass

Abstract The apple juice sample is extracted with ethyl acetate and the extract is cleaned up by elution from a silica gel column with ethyl acetate-benzene. Patulin is determined by use of a liquid chromatograph, a 25 cm Zorbax-Sil column, and a 254 nm ultraviolet detector. This method has a lower detection limit of 11 μg/L with recoveries of patulin added to apple juice >85%. Gas chromatographic-mass spectrometric analysis of the acetate derivative is used for confirmation. Patulin was detected at levels ranging from 44 to 309 μg/kg in 8 of 13 commercial samples of apple juice.

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