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Silica-gel Column Chromatographies (silica-gel + column_chromatography)
Selected AbstractsStructure Elucidation and Phytotoxicity of Ecdysteroids from Chenopodium albumCHEMISTRY & BIODIVERSITY, Issue 4 2005Marina DellaGreca The leaves of Chenopodium album were infused in H2O/MeOH. The extract treated with cold acetone gave heavy precipitation, which was removed by centrifugation. Solid material was fractionated into acidic and neutral fractions. The acidic material was subjected to different silica-gel column chromatographies, and then it was purified by reversed-phase HPLC to afford four known ecdysteroids and the new 3,,14, -dihydroxy-5, -pregn-7-ene-2,6,20-trione that were characterized by extensive spectroscopic investigation, especially by 1D- and 2D-NMR. Their effects on germination and growth of Lactuca sativa L. have been studied. The results are reported as percentage differences of germination, root elongation and shoot elongation, from the control at concentrations ranging from 10,4 to 10,7,M. [source] Chenoalbicin, a Novel Cinnamic Acid Amide Alkaloid from Chenopodium albumCHEMISTRY & BIODIVERSITY, Issue 10 2004Francesca Cutillo The roots of Chenopodium album were infused in MeOH, and the extract was partitioned between AcOEt and H2O. AcOEt-Soluble material was subjected to different silica-gel column chromatographies and then purified by reverse-phase HPLC to afford a new cinnamic acid amide alkaloid as a racemic mixture. The new compound, named chenoalbicin (1), was characterized by extensive spectroscopic investigation, especially 1D and 2D NMR spectroscopy. Its effects on the germination and growth of Lactuca sativa L. has been studied. The results are reported as percentage differences of germination, root elongation, and shoot elongation from the control at concentrations ranging from 10,4 to 10,7,M. [source] Cytotoxic Polyketides Containing Tetramic Acid Moieties Isolated from the Fungus Myceliophthora Thermophila: Elucidation of the Relationship between Cytotoxicity and StereoconfigurationCHEMISTRY - A EUROPEAN JOURNAL, Issue 24 2007Yu-Liang Yang Dr. Abstract Five new polyketides that contain tetramic acids, myceliothermophins A,E, were isolated from the thermophilic fungus Myceliophthora thermophila. Two sets of 5-alkyl-5-hydroxyl (or 5-methoxyl)-1H -pyrrol-2(5H)-one diastereomers, myceliothermophins A/B and C/D, were separated as pure compounds by using silica-gel column chromatography and recycling reverse-phase high-performance liquid chromatography (RP-HPLC). The relative configurations of the chiral centers in 5-alkyl-5-hydroxyl (or 5-methoxyl)-1H -pyrrol-2(5H)-one moieties were deduced from NOESY correlations. In the cytotoxic assay, the 5-(2-methylpropyldiene)-1H -pyrrol-2(5H)-one analogue (myceliothermophin E) exhibited inhibition against four cancer cell lines. In addition, the significant inhibitory effect of myceliothermophins A and C and the inactivity of myceliothermophins B and D revealed the importance of the relative configurations of 5-alkyl-5-hydroxyl (or 5-methoxyl)-1H -pyrrol-2(5H)-one moieties on their cytotoxicity potency against cancer cells. [source] Hydroxylation of the Triterpenoid Nigranoic Acid by the Fungus Gliocladium roseum YMF1.00133CHEMISTRY & BIODIVERSITY, Issue 2 2007Jin-Yan Dong Abstract The ability of the fungus Gliocladium roseum YMF1.00133 to transform the bioactive nigranoic acid (=(24Z)-9,19-cyclo-3,4-secolanosta-4(28),24-diene-3,26-dioic acid) was investigated. Three new products from the co-cultures of nigranoic acid and G.,roseum YMF1.00133 were obtained by employing a combination of Sephadex LH-20 and silica-gel column chromatography. The major metabolite was identified as 15, -hydroxynigranoic acid, and the minor metabolites as 6,,15, -dihydroxynigranoic acid and 7,,15, -dihydroxynigranoic acid by mass spectrometry and NMR spectroscopy. This is the first report of the biotransformation of the A-ring-secocycloartene triterpenoid, nigranoic acid. [source] | ||||||||||