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Silica Gel Column Chromatography (silica + gel_column_chromatography)
Selected AbstractsComparative in vitro and in vivo genotoxicities of 7H -benzo[c]fluorene, manufactured gas plant residue (MGP), and MGP fractionsENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 3 2004Leslie Cizmas Abstract Manufactured gas plant residue (MGP) is a complex mixture of polycyclic aromatic hydrocarbons (PAHs) that is tumorigenic in the lungs of mice. This study compared the relative genotoxicity of 7H -benzo[c]fluorene (BC), a PAH component of MGP, with MGP and MGP fractions in order to assess the contribution of BC to the genotoxicity of MGP. An MGP sample was separated into seven fractions (F1,F7) using silica gel column chromatography with petroleum ether (PE) followed by PE:acetone (99:1 v/v, then 98:2). PAHs were quantified using gas chromatography/mass spectrometry. An aliquot of F2, the fraction with the highest BC concentration and highest weighted mutagenic activity in Salmonella typhimurium strain TA98, was further separated using silica gel thin-layer chromatography with hexane. The first F2 subfraction, sF2-a, was enriched in BC and coeluting compounds and contained 35,000 ppm BC and 216,109 ppm carcinogenic PAHs (cPAHs, the sum of seven PAHs categorized by the U.S. EPA as class B2 carcinogens). The second F2 subfraction, sF2-b, contained a ninefold lower concentration of BC, with 3,900 ppm BC and 45,216 ppm cPAHs. Female ICR mice received topical application of crude MGP, crude MGP spiked with analytical-grade BC, F2, sF2-a, sF2-b, or analytical-grade BC. DNA adduct levels were analyzed by nuclease P1-enhanced 32P-postlabeling. In lung DNA of mice receiving 0.48 or 3.0 mg/mouse, net total RAL × 109 values were F2, 30.8 and 87.2; sF2-a, 24.8 and 106.7; and sF2-b, 19.6 and 151.0, respectively. Mice dosed with 0.10 mg analytical-grade BC (the mass of BC in 3.0 mg sF2-a) exhibited a net total RAL × 109 value of 7.03 in lung DNA. This was equal to approximately 7% of the total RAL × 109 value produced by 3.0 mg sF2-a. Thus, although BC appears to make an appreciable contribution to pulmonary adduct formation, the results suggest that MGP components other than BC play an important role in lung DNA adduct formation following topical MGP administration. Environ. Mol. Mutagen. 43:159,168, 2004. © 2004 Wiley-Liss, Inc. [source] Tyrosinase inhibitors isolated from the roots of Paeonia suffruticosaINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2010H. -Y. J. Cosmet. Sci., 60, 347,352 (May/June 2009) Accepted for publication November 6, 2008. Synopsis The inhibition of mushroom tyrosinase by Paeonia suffruticosa root-derived materials was evaluated. Six tyrosinase inhibitors were isolated by ethanol extraction, n -hexane, ethyl acetate, n -BuOH, and water partition, silica gel column chromatography, Sephadex LH-20, Lobar PR-8, and high-performance liquid chromatography methods, and they were identified as kaempferol (I), quercetin (II), mudanpioside B (III), benzoyloxypaeoniflorin (IV), mudanpioside H (V), and pentagalloyl-,-D-glucose (VI) on the basis of spectroscopic evidence. The inhibitory activities of compounds I to VI against mushroom tyrosinase were determined with IC50 values of 0.120, 0.108, 0.368, 0.453, 0.324, and 0.063 mM, respectively. The kinetic study indicated that all purified inhibitors acted competitively for the L-dopa binding site of the enzyme, with an exception of compound VI, which acted non-competitively. [source] Synthesis of 14C-labelled myosmine, [2,- 14C] -3-(1-pyrrolin-2-yl)pyridineJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 5 2003Stefan Tyroller Abstract 14C-Labelled myosmine ([2,- 14C]-3-(1-pyrrolin-2-yl)pyridine) was synthesized for autoradiography studies starting from [carboxyl- 14C]-nicotinic acid by initial esterification of the latter in the presence of 1,1,1-triethoxyethane. Without any purification the ethyl nicotinate formed was directly reacted with N -vinyl-2-pyrrolidinone in the presence of sodium hydride, yielding 14C-labelled myosmine. The product was purified by silica gel column chromatography. The radiochemical yield was 15% and the specific activity 55.2 mCi/mmol. Copyright © 2003 John Wiley & Sons, Ltd. [source] Different antibacterial actions of isoflavones isolated from Erythrina poeppigiana against methicillin-resistant Staphylococcus aureusLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2006M. Sato Abstract Aims:, To screen six isoflavones isolated from Erythrina poeppigiana (Leguminosae) for their antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). Methods and Results:, Stem bark of E. poeppigiana was macerated with acetone and the methylene chloride-soluble fraction of the residue was applied to repeated silica gel column chromatography and eluted. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by a broth dilution method. Inactive compounds that failed inhibiting bacterial growth at 25 ,g ml,1 were further investigated for their combination effects with methicillin and oxacillin. Of the isolated isoflavones, 5,7,4,-trihydroxy-8,3,-di(,,, -dimethylallyl)isoflavone (isolupalbigenin) exhibited the highest anti-MRSA activity (MICs: 1·56,3·13 ,g ml,1; MBCs: 6·25,12·5 ,g ml,1), followed by 5,7,4,-trihydroxy-6- ,,, -dimethylallylisoflavone (erythrinin B). Inactive compounds were combined with methicillin or oxacillin, 5,4,-dihydroxy-(3,,,4,,-dihydro-3,,-hydroxy)-2,,,2,,-dimethylpyrano[5,,,6,,:6,7]isoflavone (M-Wi-2) intensifying the susceptibility of MRSA strains to these antibiotics. In all but one strain, the MIC values of methicillin were reduced from ,100 to 6·25,12·5 ,g ml,1 in the presence of M-Wi-2 (25 ,g ml,1). Conclusions:, Isoflavones from E. poeppigiana showed two different antibacterial activities against MRSA: direct growth inhibition and intensification of methicillin sensitivity. Significance and Impact of the Study:, Isolupalbigenin and M-Wi-2 could lead to the development of compounds for new approaches against MRSA infection. [source] Compounds from Ageratum conyzoides: isolation, structural elucidation and insecticidal activityPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 6 2007Márcio D Moreira Abstract This work aimed at identifying plant compounds with insecticidal activity against Diaphania hyalinata (L.) (Lepidoptera: Pyralidae), Musca domestica (L.) (Diptera: Muscidae), Periplaneta americana (L.) (Blattodea: Blattidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetaefolia L.), Jimson weed (Datura stramonium L.), ,baleeira' herb (Cordia verbenaceae L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.) and billy goat weed (Ageratum conyzoides L.). Firstly, the insecticidal activities of hexane and ethanol plant extracts were evaluated against adults of R. dominica. Among them, only the hexane extract of A. conyzoides showed insecticidal activity. The hexane extract of this plant species was therefore fractionated by silica gel column chromatography to isolate and purify its bioactive chemical constituents. Three compounds were identified using IR spectra, 1H NMR, 13C NMR, HMBC and NOE after gel chromatography: 5,6,7,8,3,, 4,, 5,-heptamethoxyflavone, 5,6,7,8,3,-pentamethoxy-4,, 5,-methylenedioxyflavone and coumarin. The complete assignment of 13C NMR to 5,6,7,8,3,-pentamethoxy-4,, 5,-methylenedioxyflavone was successfully made for the first time. 5,6,7,8,3,-Pentamethoxy-4,, 5,-methylenedioxyflavone did not show any insecticidal activity against the four insect species tested. 5,6,7,8,3,, 4,, 5,-Heptamethoxyflavone showed low activity against D. hyalinata and R. dominica and was not toxic to M. domestica or P. americana. In contrast, coumarin showed insecticidal activity against all four insect pest species tested, with the following order of susceptibility: R. dominica < P. americana < D. hyalinata < M. domestica after 24 h exposure. Copyright © 2007 Society of Chemical Industry [source] | |||||||||||||