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  • Author or Editor: Wojciech Cisowski x
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Natural phenolic compounds, e.g. ellagitannins, gallotannins, and flavonoid glycosides, from the aerial parts of Erodium cicutarium ( Geraniaceae ) have been isolated and identified. The structures of these compounds were determined by conventional methods of analysis and confirmed by MS and NMR spectral analysis. The distribution of tannins and flavonoids in E. ciconium, E. cicutarium, E. manescavi , and E. pelargoniiflorum were examined by TLC on unmodified silica gel and on silica gel chemically modified with polar and nonpolar groups (HPTLC Si 60, HPTLC Si 60 LiChrospher, HPTLC diol, HPTLC CN, and HPTLC RP-18W).

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Oxindole alkaloids are the main constituents of Uncaria tomentosa (Willd.) DC and are regarded as marker compounds of this plant. A trichloroethylene extract of crushed bark from Uncaria tomentosa was chromatographed by TLC on unmodified silica gel and on silica gel chemically modified with polar and non-polar groups to determine the best separation of the alkaloids present in the extract.

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Caffeetannins and flavonoid glycosides have been analyzed in polar solvent extracts from leaves of Mentha piperita (Lamiaceae) . Peppermint extracts and individual compounds isolated from the leaves were investigated by TLC with horizontal development on unmodified silica gel (HPTLC Si 60, HPTLC LiChrospher Si 60) and on silica gel chemically modified with polar (HPTLC NH 2 , HPTLC CN) and non-polar groups (HPTLC RP-18W). The mobile phase acetone-acetic acid, 85 + 15 ( v/v ), enabled successful separation on the aminopropyl adsorbent; water-methanol, 60 + 40 ( v/v ), was best on the octadecyl adsorbent. These simple methods can be very useful for rapid estimation of components of peppermint leaves or extracts.

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Gradient thin-layer chromatography and densitometric determination have been applied to the qualitative and quantitative analysis of three phenolic acids — gallic acid, caffeic acid, and protocatechuic acid in three species from the Polygonaceae family. Free phenolic acids and those liberated after alkaline and enzymatic hydrolysis were analyzed.

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Thin-layer chromatography with densitometric detection has been used for qualitative and quantitative analysis of the myricitrin content of extracts of the leaves of 20 species of the Aceraceae family. The presence of myricitrin was confirmed in five of the samples. The mobile phase was optimized for quantitative analysis of myricitrin without extract purification. Myricitrin standard was obtained from one of the extracts; its identity was confirmed chromatographically and by use of spectral methods. Implications for chemotaxonomic and phytochemical research are discussed.

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Conditions have been established for TLC separation of a mixture of nine quinolizidine alkaloid standards (lupanine, methylcytisine, cytisine, hydroxylupanine, sophocarpine, lusitanine, retamine, sparteine, and l - α -isosparteine) and of alkaloid fractions from a variety of Genista species and from in-vitro cultures of members of this species. Optimization of the one-dimensional TLC separation of the nine alkaloid standards was performed on two types of layer, RP-18W and silica gel. The mixture of standards was also chromatographed by two-dimensional TLC on diol F 254S layers and by 2D TLC with an adsorbent gradient. In the last variant (so-called graft TLC) the first development was performed on a TLC diol plate and the second, in the perpendicular direction, on an RP-18W TLC plate. Only by 2D TLC with an adsorbent gradient was it possible to achieve full separation both of the standards and of alkaloid fractions from plant material. Under these conditions the presence of retamine, cytisine, sparteine, l - α -isosparteine, lupanine, and methylcytisine was discovered in all Genista species and in shoot cultures of G. tinctoria .

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