Proanthocyanidins from Ribes nigrum leaves : TLC Analysis

peer reviewedIn summary, the main oligomeric prodelphinidins of Ribes nigrum leaves can be identified by HPTLC; this method could also be utilized as a proanthocyanidin screen for determining their occurrence in other plants and for quantification of the major dimers

A Densitometric Method for the Determination of Three Clinically Important Monosaccharides in Urine

peer reviewedA quantitative, densitometric, thin layer chromatographic method has been developed for the determination of three clinically important monosaccharides in ureine, after desalting.The analysis of these monosaccharides in urine allows to observe the potential changes induced by antiinflammatories in human small intestine permeability. Xylose, 3-O-methylglucose and rhamnose were estimated quantitatively in urine; arabinose was used as internal standard. The densitometry was performed at a wavelenght of 400 nm after a visualization reaction on HPTLC plates. In all cases, coefficients of variation of the method were less than 2.7%

Densitometric Determination of Salicin in Willow Stem Bark

peer reviewedMost of the salicin present in willow stem bark occurs as labile glycosides (e.g. salicin, salicortin, 2-O'-acetylsalicortin, 3-O'-acetylsalicortin, tremulacin and fragilin). On alkaline hydrolysis, these acylated derivatives decompose to salicin; in this way, the total amount of salicin can be determined. A HPTLC method has been developed for the quantitative determination of salicin in stem bark before and after alkaline hydrolysis. The mobile phase used for the separation is a modification of one described in the literature. a double or triple migration is necessary to separate salicin from other components of the extract. The results have been compared with those obtained after bidimensional chromatography using two phases described for the quantitative evaluation of salicin. to check that separation was complete, the spectrum of salicin obtained from willow extracts was superimposed on that of a salicin standard.Quantification was performed at lambda = 270nm, the wavelenght of maximum absorption in the IV spectrum of salicin

Quantitative Densitometric Evaluation of Harpagoside in the Secondary Roots of Harpagophytum procumbens D.C.

peer reviewedHarpagophytum procumbens D.C. (Devil's Claw) secondary roots are used in Europe as a home remedy for lack of appetite, dyspeptic complaints, and in supportive therapy for degenerative disorders of the locomotor system. The main characteristic iridoid glucoside of the plant is harapagoside. An HPTLC method has been developed for the quantitative determination of harpagoside in the secondary roots and extracts of this plant. The mobile phase used is an optimized version of one described in the literature.It furnished the most homogenous spots for quantitative densitometric evaluation ( at lambda= 286 nm, the wavelenght of maximum absorption for harapgoside).The results have been compared with those obtained afetr visualization with sulfuric acid-vanillin reagent and those obtained using a previously published HPLC method; To check that separation was complete, the spectra of harpagoside obtained from Devil's Claw extracts before and after visualization were superimposed on thos of harpagoside standard

Semi-Quantitative Salicin Analysis According the German Pharmacopoeia (DABX): Avoidance of Picein Interference

The semi-quantitative determination of salicin by TLC described in the German Pharmacopoeia (DABX) does not separate salicin from picein, another phenolic glycoside of some willow species. In this paper we propose to combine the use of both an adequate mobile phase and a suitable reagent (vanillin reagent instead of sulfuric acid-thymol) for an unambiguous determination of the amount of salicin.

Densitometric Evaluation of Gentiopicroside in the Roots of Gentiana lutea L.

peer reviewedAs no satisfactory method existed for the separation of gentiopicroside from other components of gentian roots, we have decided to undertake some experiments.In this communication, we report the use of a novel mobile phase and a different detection system. Our HPTLC method is a fast and reliable procedure which may be used for quantification of gentiopicroside in roots and extracts of Gentiana lutea, whether for routine analysis or for studying stability. The TLC method is also compared with an HPLC method