Objective: To investigate the effect of temperature and pressure on supercritical CO_2 extraction of Triognella foenum graecum Linn seeds, to determine the optimal condition which leads to highest percentage of the ac...Objective: To investigate the effect of temperature and pressure on supercritical CO_2 extraction of Triognella foenum graecum Linn seeds, to determine the optimal condition which leads to highest percentage of the accumulative yield and revealing the chemical composition of supercritical CO_2 extract.Methods: Temperatures in the range of 40–60C and pressures in the range of 10–25 MPa were used. FTIR and GC–MS analysis were used to detect the bioactive compounds present in the extract. The broth dilution method and slope method were used to evaluate the anti-microbial and anti-tuberculosis activities and the in vitro anti-malarial assay was carried out according to the micro assay protocol of Rieckmann and his coworkers.Results: The temperature was more affected than the pressure on the extraction performance and the highest yield of the extract(3.111%) was attained at 60C and 10 MPa.FTIR and GC–MS showed that the chemical composition of the extract included conjugated linoleic acid methyl ester as the major active principle(with concentration of72.28%), followed by saturated fatty acid methyl esters(16.03%), steroids(8.09%) and organic siloxane compound(3.61%). The extract showed moderate anti-bacterial activity with MIC values 100, 250, 125 mg/m L towards Escherichia coli, Staphylococcus aureus and Streptococcus pyogenus respectively. It exhibited high inhibition effect towards the fungi Candida albican with MFC value(250 mg/m L). The extract had low antituberculosis activity with MIC value(100 mg/m L) and comparable MIC value(0.29 mg/m L) towards Plasmodium flaciparum.Conclusions: Supercritical CO_2 extraction as alternate and green technology is performed successfully to extract the bioactive compounds from the seeds of T. foenum graecum Linn and it is concluded that this extract can be used as an alternate source of synthetic anti-biotic drugs.展开更多
Various 2-arylbenzimidazoles were synthesized from o-phenylenediamine and aldehydes via one-step process using DMP （Dess-Martin-periodinane） reagent as an oxidant. The method was proved to be simple, convenient and ...Various 2-arylbenzimidazoles were synthesized from o-phenylenediamine and aldehydes via one-step process using DMP （Dess-Martin-periodinane） reagent as an oxidant. The method was proved to be simple, convenient and the products were isolated with good yields （80-90%）. ？2009 Charansingh H. Gill. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
A series of CeO2-Al2O3, CeO2-TiO2, CeO2-ZrO2, and CeO2-SiO2 mixed-oxide supported copper catalysts were prepared by a modified deposition-precipitation method from ultra dilute aqueous solutions and were investigated ...A series of CeO2-Al2O3, CeO2-TiO2, CeO2-ZrO2, and CeO2-SiO2 mixed-oxide supported copper catalysts were prepared by a modified deposition-precipitation method from ultra dilute aqueous solutions and were investigated for hydrogenolysis of cellulose in aqueous medium, in the presence of hydrogen to produce sorbitol as major product. Among all the catalysts tested in the present work, CuO/CeO2ZrO2?catalyst proved to be the most promising with high conversion (92%) and excellent selectivity (sorbitol 99.1%), at an intermediate reaction temperature of 245°C in a neutral aqueous solution without an aid of liquid phase acid. The catalyst was recyclable in repeated runs and no deactivation was observed even after five reaction cycles. CuO/CeO2-ZrO2 has been characterized by XRD, SEM, TPR and BET surface area techniques.展开更多
基金acknowledge to Hodeidah University, Yemen for supporting this work
文摘Objective: To investigate the effect of temperature and pressure on supercritical CO_2 extraction of Triognella foenum graecum Linn seeds, to determine the optimal condition which leads to highest percentage of the accumulative yield and revealing the chemical composition of supercritical CO_2 extract.Methods: Temperatures in the range of 40–60C and pressures in the range of 10–25 MPa were used. FTIR and GC–MS analysis were used to detect the bioactive compounds present in the extract. The broth dilution method and slope method were used to evaluate the anti-microbial and anti-tuberculosis activities and the in vitro anti-malarial assay was carried out according to the micro assay protocol of Rieckmann and his coworkers.Results: The temperature was more affected than the pressure on the extraction performance and the highest yield of the extract(3.111%) was attained at 60C and 10 MPa.FTIR and GC–MS showed that the chemical composition of the extract included conjugated linoleic acid methyl ester as the major active principle(with concentration of72.28%), followed by saturated fatty acid methyl esters(16.03%), steroids(8.09%) and organic siloxane compound(3.61%). The extract showed moderate anti-bacterial activity with MIC values 100, 250, 125 mg/m L towards Escherichia coli, Staphylococcus aureus and Streptococcus pyogenus respectively. It exhibited high inhibition effect towards the fungi Candida albican with MFC value(250 mg/m L). The extract had low antituberculosis activity with MIC value(100 mg/m L) and comparable MIC value(0.29 mg/m L) towards Plasmodium flaciparum.Conclusions: Supercritical CO_2 extraction as alternate and green technology is performed successfully to extract the bioactive compounds from the seeds of T. foenum graecum Linn and it is concluded that this extract can be used as an alternate source of synthetic anti-biotic drugs.
文摘Various 2-arylbenzimidazoles were synthesized from o-phenylenediamine and aldehydes via one-step process using DMP （Dess-Martin-periodinane） reagent as an oxidant. The method was proved to be simple, convenient and the products were isolated with good yields （80-90%）. ？2009 Charansingh H. Gill. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘A series of CeO2-Al2O3, CeO2-TiO2, CeO2-ZrO2, and CeO2-SiO2 mixed-oxide supported copper catalysts were prepared by a modified deposition-precipitation method from ultra dilute aqueous solutions and were investigated for hydrogenolysis of cellulose in aqueous medium, in the presence of hydrogen to produce sorbitol as major product. Among all the catalysts tested in the present work, CuO/CeO2ZrO2?catalyst proved to be the most promising with high conversion (92%) and excellent selectivity (sorbitol 99.1%), at an intermediate reaction temperature of 245°C in a neutral aqueous solution without an aid of liquid phase acid. The catalyst was recyclable in repeated runs and no deactivation was observed even after five reaction cycles. CuO/CeO2-ZrO2 has been characterized by XRD, SEM, TPR and BET surface area techniques.
