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Concept: Silica gel


A new sildenafil analogue was found to be added illegally to a energy drink marketed for the enhancement of sexual function. The structure was determined as 1-[4-propoxy-3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)phenylsulfonyl]-4-methylpiperazine. Owing to the inclusion of one more methyl group to sildenafil (on C-21), the detected compound was called “propoxyphenyl sildenafil”. The sample was purified with column chromatography. The UV, IR, LC/MS (ESI) and completely assigned NMR data of propoxyphenyl sildenafil is reported. Having compared the structure with sildenafil, the results showed that the 2-ethoxy group (at the position on C-19) has been replaced by propoxy group.

Concepts: Sociology, Chromatography, High performance liquid chromatography, Group, Set, Ring, Expanded bed adsorption, Silica gel


A new acetylated chalcone glycoside, trans-2',6'-dihydroxy-4'-O-(4″-acetyl-rhamnoside)-4-methoxychalcone (1) and a new biflavonoid glycosides, 5,3',5″,4″'-tetrahydroxy-3″',5″'dimethoxy-biflavone (4' → 8″)-7-O-((2-rhamnoside) rhamnoside) (2) were isolated from the ethyl acetate soluble fraction of the methanol extract obtained from Trigonosciadium brachytaenium and have been purified by column chromatography and preparative TLC. Those structures were elucidated by UV, (1)H NMR and (13)C NMR, HMBC, EI-MS and IR spectra. The antioxidant activity of ethyl acetate extract was evaluated by 1,1-diphenyl-2-picrylhydrazyl method. The results indicate that ethyl acetate extract from aerial part of T. brachytaenium possesses considerable antioxidant activity.

Concepts: Chromatography, Acetic acid, Solvent, Glycoside, Infrared, Ethyl acetate, Silica gel, Rhamnose


SUMMARY The present study was designated to ascertain the anthelmintic activity of the rhizomes of Paris polyphylla and to isolate and characterize the active constituents. The methanol extract from rhizomes of P. polyphylla showed significant anthelmintic activity against Dactylogyrus intermedius with the median effective concentration (EC50) 22·5 mg L-1. Based on this finding, the methanol extract was fractionated by silica gel column chromatography in a bioassay-guided fractionation yielding 2 bioactive compounds, the structures of these compounds were elucidated as formosanin C and polyphyllin VII. The in vivo tests revealed that formosanin C and polyphyllin VII were significantly effective against D. intermedius with EC50 values of 0·6 and 1·2 mg L-1, respectively. The acute toxicities (LC50) of formosanin C and polyphyllin VII for grass carp were 2·8 and 2·9 mg L-1, respectively. The overall results provide important information for the potential application of formosanin C and polyphyllin VII in the therapy of serious infection caused by D. intermedius.

Concepts: Ethanol, Chemical equilibrium, Chromatography, High performance liquid chromatography, Column chromatography, Thin layer chromatography, Silica gel, Fractionation


A reversed phase chromatographic system, composed of a stationary phase of C silica gel (ODS, 20μm) and a mobile phase of ethanol/water, was used to separate liquiritin and liquiritigenin in the raw material of flavonoids. The linear adsorption isotherm and the equilibrium-dispersive model were adopted to approximatively describe the chromatographic separation behaviors of liquiritin and liquiritigenin in the raw material under different column temperatures, ethanol contents and flow rates of the mobile phase, sample concentrations and feeding times. Combined with orthogonal design, the ED model was used to optimize the chromatographic separating conditions, the corresponding experimental result with a good agreement was obtained and the overload separation was realized.

Concepts: Chromatography, Analytical chemistry, Gas chromatography, Thin layer chromatography, Separation, Silica gel, Jane Arden, Jack Bond


Reactions of 2,2-dialkylaldehydes with electron-rich 2-naphthols and para-substituted phenols in presence of catalytic amount of [Formula: see text]-TSA under closed vessel solvent-free microwave irradiation conditions resulted in formation of corresponding 2,2-dialkyl-1,2-dihydronaphtho[2,1-[Formula: see text]]furans and 2,2-dialkyl-2,3-dihydrobenzofurans, respectively, in good to excellent yields. The effect of stoichiometry, temperature, and catalyst in reaction progress was systematically investigated. 14-Alkyl-[Formula: see text]-dibenzo[[Formula: see text]]xanthenes was obtained as minor products when 2-naphthol and 6-bromo-2-naphthols were used as starting phenols. Simple phenols gave a lower yield of the 2,2-dialkyl-2,3-dihydrobenzofurans products than their electron-rich naphthalene counterparts. Also, xanthene-type products were not detected in case of simple phenols by GC-MS or column chromatography.

Concepts: Chemical reaction, Catalysis, Chemical equilibrium, Chromatography, High performance liquid chromatography, Yield, Expanded bed adsorption, Silica gel


In this study Monascus strains were screened for lovastatin production. These strains namely Monascus purpureus, Monascus sanguineus and their co-culture were able to produce lovastatin in solid state fermentation. Sensitivity of lovastatin was tested on Saccharomycess cerevaceae and Candida sp. where the former exhibited large zone of inhibition as compared to the latter. Presence of lovastatin was confirmed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Quantification of lovastatin was done with UV spectrometer at 238 nm. Further, Plackett-Burman methodology was applied for screening of nutrients for lovastatin production. Different substrates were screened and amongst them, wheat bran was found to be the best substrate for lovastatin synthesis. Seven nutrients were screened according to the Plackett-Burman design for lovastatin yield. MgSO4.7H2O showed the positive impact on lovastatin yield whereas lactose showed the maximum negative effect with M. purpureus. For M. sanguineus, CaCl2.2H2O displayed the dominant negative effect and soybean the significant positive. With co-culture, the effect of lactose was positive whereas that of malt extract was negative and dominant. The maximum lovastatin yield for M. sanguineus, M. purpureus and co-culture was estimated to be 0.402, 0.27 and 0.26 mg/g respectively.

Concepts: Enzyme, Chromatography, High performance liquid chromatography, Thin layer chromatography, Paper chromatography, Silica gel, Malt, Monascus purpureus


40 isoeugenol-tolerant yeasts were isolated from the rhizosphere soil samples which in turn were collected from aromatic plants in different regions of Iran, and further tested for their ability to grow on a minimal medium containing isoeugenol as the sole carbon and energy source. Nine isolates which were able to grow on isoeugenol were examined for their ability to convert isoeugenol into vanillin under growing cell experiments. Of the tested yeasts, the highest conversion efficiency was observed in isolate MP24. The isolate was identified as Trichosporon asahii based on morphological, biochemical and molecular (ITS region) characters and tested to effectively convert isoeugenol into vanillin under resting cell system. A comparative analysis of thin layer chromatography (TLC), UV-Vis spectrometry, and high-performance liquid chromatography (HPLC) verified that vanillin and vanillic acid are accumulated as two major metabolites using T. asahii strain MP24 resting cells. In the presence of 7.5 g/l of wet weight cells of the strain MP24 pre-grown on isoeugenol and harvested at the end of the exponential growth phase, the optimal concentration of vanillin reached 2.4 g/l with a molar conversion of 52.5% in the potassium phosphate buffer (100 mM, pH 5.8) supplemented with 5 g/l of isoeugenol and 2% (v/v) N,N-dimethylformamide (DMF). The total concentration of vanillin and vanillic acid obtained from the bioconversion process was 4.2 g/l (total molar yield of 88.3%). Until now, no data has been published on the conversion of isoeugenol into vanillin by the strains of the genus Trichosporon.

Concepts: DNA, Protein, Chromatography, High performance liquid chromatography, Thin layer chromatography, Paper chromatography, Bacterial growth, Silica gel


Nine antialgal active compounds, (i.e. trehalose (1), twenty-two methyl carbonate (2), (-)-dihydromenisdaurilide (3), 3,7,11,15-tetramethyl-2-hexadecen-1-ol (4), isophytol (5), 8-hexadecenol (6), 17-hydroxyheptadecanoic acid (7), trans-asarone (8) and 2-amino-3-mercaptopropanoic acid (9)) were isolated from Ulva pertusa for the first time by sephadex LH-20 column chromatography, silica gel column chromatography and repeated preparative TLC. Except for compound 4, all compounds represented novel isolated molecules from marine macroalgae. Further, antialgal activities of these compounds against Amphidinium carterae, Heterosigma akashiwo, Karenia mikimitoi, Phaeocystis globosa, Prorocentrum donghaiense and Skeletonema costatum were investigated for the first time. Results showed these nine compounds have selectivity antialgal effects on all test red tide microalgae, and antialgal activities against red tide microalgae obviously enhanced with the increase of concentration of antialgal compounds. Based on this, EC50-96 hvalues of these nine compounds for six red tide microalgae were obtained for the first time. By analyzing and comparing EC50-96 hvalues, it has been determined that seven compounds (1, 3, 4, 6, 7, 8 and 9) showed the superior application potential than potassium dichromate or gossonorol and other six compounds as a characteristic antialgal agent against Heterosigma akashiwo, Karenia mikimitoi and Prorocentrum donghaiense. Overall this study has suggested that green algae Ulva pertusa is a new source of bioactive compounds with antialgal activity.

Concepts: Algae, Chromatography, High performance liquid chromatography, Chemical compound, Column chromatography, Thin layer chromatography, Expanded bed adsorption, Silica gel


Studies in molecular ecology depend on field-collected samples for genetic information, and the tissue sampled and preservation conditions strongly affect the quality of the DNA obtained. DNA yields from different tissue types have seldom been compared, and the relative performance of storage media has never been directly tested, even though these media may influence DNA degradation under field conditions. We analyzed DNA yield from buccal swabs and wing punches harvested from live bats using nucleic acid quantification as well as quantitative PCR for a single-copy nuclear locus. We also compared DNA yields from wing tissue preserved in three media: ethanol, NaCl-saturated dimethyl sulfoxide (DMSO), and silica desiccant. Wing punches yielded more total DNA than did buccal swabs, and wing tissues preserved in silica beads yielded significantly more total and nuclear DNA than those preserved in DMSO or ethanol. These results show that tissue type and preservation media strongly influence the quantity of DNA obtained from non-lethal genetic samples, and based on these effects we provide recommendations for field collection of tissues for genetic analyses.

Concepts: Sample, DNA, Genetics, Molecular biology, Nucleic acid, Dimethyl sulfoxide, Silica gel, Dimethyl sulfide


Described herein is an effective and practical modular flow design for the meta-selective C-H arylation of anilines. The design consists of four continuous-flow modules (i.e., diaryliodonium salt synthesis, meta-selective C-H arylation, inline copper extraction, and aniline deprotection) which can be operated either individually or consecutively to provide direct access to meta-arylated anilines. With a total residence time of 1 hour, the desired product could be obtained in high yield and excellent purity without the need for column chromatography, and the residual copper content meets the standards for parenterally administered pharmaceutical substances.

Concepts: Chromatography, High performance liquid chromatography, Module, Expanded bed adsorption, Silica gel, Modulus