TLC Comparison Research Articles

Alkaloids and coumarins from Ruta chalepensis

The aerial parts of Ruta chalepensis yielded the alkaloids kokusaginine, skimmianine, arborinine, γ-fagarine, graveoline and the new alkaloid 3′-hydroxygraveoline, as well as the coumarins chalepensin, chalepin, rutamarin, bergapten, isopimpinellin and xanthotoxin. The structures were established by spectral methods and by TLC comparison with authentic samples where possible. Some alkaloids were tested for their effects on the prevention of early pregnancy in rats, but none was found to be active.

Aridicins, novel glycopeptide antibiotics. II. Isolation and characterization.

A new antibacterial antibiotic complex, aridicin, was produced by a new genus, Kibdelosporangium aridum (SK&F-AAD-216). The individual factors, aridicins A, B and C, were isolated from the fermentation broth by an Amberlite XAD-7 resin extraction and purified by preparative reversed phase HPLC. The aridicins were found to be novel members of the glycopeptide class of antibiotics as exemplified by ristocetin and vancomycin, based on chemical and spectroscopic data, their molecular weights as determined by FAB mass spectrometry (1,786, 1,800 and 1,814), the detection of actinoidinic acid in their acid hydrolysates, and detailed TLC and HPLC comparisons with representative members of this class.

Identification of natural tricetin-derived C-glycosides through synthesis

C-Glycosylation of 5,7-dihydroxy-3′,4′,5′-trimethoxyflavone was carried out with acetobromo-α- d-glucose, -α- d-galactose, -α- d-xylose, -β- l-arabinose and -αt-L-rhamnose. The respective 6-C-glycosides and 6, 8-di- C-glycosides (excepted for galactose) were isolated and permethylated. MS and TLC comparison confirmed the proposed structures of five natural tricetin-derived C-glycosides.

Hepatic metabolism of glycodehydrocholic acid in the dog and rat.

SummaryOur results demonstrate extensive metabolism of GDCA in the dog and rat by a pathway similar to that for DCA in man (7). Assignment of reduced metabolites and relative ratios was made by tlc comparison of tritiated metabolites with known compounds. Trace bolus doses of GDCA result in complete reductive metabolism, and increasing molar doses result in the excretion of only small amounts (<5%) of unchanged GDCA in bile. Thus our in vivo experiments are in contrast to the absence of GDCA metabolism reported in the isolated, perfused rat liver (12).The authors are indebted to Ruthie Pettigrew and Becky Backof for invaluable technical assistance and to Jo Ellen Shockley for preparation of the manuscript.

ChemInform Abstract: STUDIES ON ANTIANAPHYLACTIC AGENTS. 6. SYNTHESIS OF SOME METABOLITES OF 6‐ETHYL‐3‐(1H‐TETRAZOL‐5‐YL)CHROMONE AND THEIR ANALOGS

AbstractMetaboliten des Chromons (VIIa) und analoge Verbindungen werden auf den im Formelschema beschriebenen Wegen dargestellt und im PCA‐Test an Ratten auf antianaghylaktische Wirkung geprüft.

Studies on antianaphylactic agents. 6. Synthesis of some metabolites of 6-ethyl-3-(1H-tetrazol-5-yl)chromone and their analogs

The metabolites of 6-ethyl-3-(1H-tetrazol-5-yl)chromone (AA-344) (1), an orally effective antiallergic agent, and their analogues were synthesized to confirm the proposed structures and to determine their activity in the rat passive cutaneous anaphylaxis (PCA) test. A glucuronic acid metabolite (6) was assigned the structure 24b, 1-deoxy-1-[5-(6-ethylchromon-3-yl)tetrazol-1-yl]-beta-D-glucopyranuronate, by the comparison of 13C NMR, mass spectra, and TLC of isomeric compounds. In 13C NMR spectra, the shift difference of the tetrazole ring carbons between a pair of isomers was more remarkable than that of the glycosidic carbons. Therefore, the former is a useful criterion for distinguishing between such isomers. Some of the metabolities and analogues were active when administered intravenously, and two metabolites (2 and 3) were also effective upon oral administration.

Comparison of log k′ — solvent composition relationships in thinlayer and column chromatography for systems of the type: Silanized silica — water + methanol

AbstractRelationships between log k' values of polynuclear hydrocarbons and composition of water/methanol mixtures were determined for HPTLC on RP‐18 silica and for HPLC using RP‐2 silica. In spite of differences in the adsorbents used, a good correlation between HPLC and TLC parameters was found. In the TLC experiments, a sandwich tank with a modified solvent distributor was used.It has been reported that thin‐layer chromatography is a good technique for the preliminary optimization of column chromatographic separations [1–5]. So far, the comparison of TLC and HPLC has been mainly restricted to silica as the adsorbent. Since TLC plates precoated with silanized adsorbents recently became commercially available, it seemed interesting to compare the chromatographic parameters obtained for the “reversed phase” systems with the two techniques (see also ref. 6).

N-feruloylglycyl- l-phenylalanine: A sequence in barley proteins

N-Feruloylglycyl- l-phenylalanine was obtained from barley globulins by partial hydrolysis with 4 N HCl. It was isolated by means of preparative and ‘multiple elimination’ TLC (METC) and further identified by TLC comparison with a synthetic sample. Additional proof for its identity was obtained by UV, fluorescence and IR spectroscopy and by the action of carboxypeptidase A. The possible role of N-feruloylglycine as a starter in protein biosynthesis in the barley seed is discussed.

Limonoic acid A-ring lactone, a new limonin derivative in Citrus

A nonbitter derivative of limonin (the intensely bitter tetracyclic dilactone of Citrus seeds) has been found to occur in the fruit tissues of Citrus sinensis (L.) Osbeck and C. paradisi Macf. The new compound, for which the name limonoic acid A-ring lactone is proposed, is one of the two possible monolactones which can be derived from limonin by partial hydrolysis. It was identified as the A-ring monolactone by TLC and paper electrophoretic comparison with the authentic compound and by its facile conversion into limonin. Indications were found of an enzyme in tissue extracts which converts limonoic acid A-ring lactone into limonin.