由于纳米金的许多性能均取决于其粒径,因此制备粒径可控的纳米金是非常重要的。本文采用绿色还原法,以氯金酸溶液为前驱体、辣椒提取液为保护剂和还原剂,通过改变反应条件制备了纳米金粒子。采用X射线衍射仪、红外光谱仪、紫外-可见分...由于纳米金的许多性能均取决于其粒径,因此制备粒径可控的纳米金是非常重要的。本文采用绿色还原法,以氯金酸溶液为前驱体、辣椒提取液为保护剂和还原剂,通过改变反应条件制备了纳米金粒子。采用X射线衍射仪、红外光谱仪、紫外-可见分光光度计、马尔文粒径分析仪、透射电镜、场发射扫描电镜和能谱仪等对所制备的样品进行了表征。结果显示,此法所制备溶胶中的金粒子均一性较好,为球状的纳米粒子,主要成分为单质金;分散性较好,粒径较小,SEM分析表明其平均粒径约为25 nm。辣椒提取液用量、氯金酸溶液用量等反应条件对溶胶中金粒子的形貌和粒径有着较大影响。在室温下,当辣椒提取液用量为15 m L,氯金酸溶液用量为10 m L时,所得到的纳米金粒子的粒径最小。辣椒提取液中含有多羟基化合物,能将氯金酸还原成金原子,随后金原子在提取物长链高分子位阻效应下组装成纳米金粒子。展开更多
In our continuing search of discovering bioactive substances from marine organisms, a sample of soft coral Sarcophyton crassocaule Mosre collected off the Sanya bay, China, was investigated. Two polyhydroxylated stero...In our continuing search of discovering bioactive substances from marine organisms, a sample of soft coral Sarcophyton crassocaule Mosre collected off the Sanya bay, China, was investigated. Two polyhydroxylated sterols 1 and 2 were isolated from the 95% ethanol extract of the sample by chromatography over silica gel. Compound 1, named sarcrasterol, was a new compound, its structure was established as(22R*,24ξ)-methyl-cholest-5-en-3β,22α,25,28-tetraol by spectroscopic methods. Compound 2, a known compound, was first obtained by Kobayashi, however, the relative configuration of C24 has not been determined yet. This paper reports the stereochemistry of compound 2 established as (24S*)-methyl cholest-3β,5β,6α,25-tetraol by means of X-ray single crystal diffraction analysis. Bioassay results show that compound 2 has a moderate activity against human tumor cell lines MGC-803 with an IC50 value of 23.0 μg/mL.展开更多
文摘由于纳米金的许多性能均取决于其粒径,因此制备粒径可控的纳米金是非常重要的。本文采用绿色还原法,以氯金酸溶液为前驱体、辣椒提取液为保护剂和还原剂,通过改变反应条件制备了纳米金粒子。采用X射线衍射仪、红外光谱仪、紫外-可见分光光度计、马尔文粒径分析仪、透射电镜、场发射扫描电镜和能谱仪等对所制备的样品进行了表征。结果显示,此法所制备溶胶中的金粒子均一性较好,为球状的纳米粒子,主要成分为单质金;分散性较好,粒径较小,SEM分析表明其平均粒径约为25 nm。辣椒提取液用量、氯金酸溶液用量等反应条件对溶胶中金粒子的形貌和粒径有着较大影响。在室温下,当辣椒提取液用量为15 m L,氯金酸溶液用量为10 m L时,所得到的纳米金粒子的粒径最小。辣椒提取液中含有多羟基化合物,能将氯金酸还原成金原子,随后金原子在提取物长链高分子位阻效应下组装成纳米金粒子。
文摘In our continuing search of discovering bioactive substances from marine organisms, a sample of soft coral Sarcophyton crassocaule Mosre collected off the Sanya bay, China, was investigated. Two polyhydroxylated sterols 1 and 2 were isolated from the 95% ethanol extract of the sample by chromatography over silica gel. Compound 1, named sarcrasterol, was a new compound, its structure was established as(22R*,24ξ)-methyl-cholest-5-en-3β,22α,25,28-tetraol by spectroscopic methods. Compound 2, a known compound, was first obtained by Kobayashi, however, the relative configuration of C24 has not been determined yet. This paper reports the stereochemistry of compound 2 established as (24S*)-methyl cholest-3β,5β,6α,25-tetraol by means of X-ray single crystal diffraction analysis. Bioassay results show that compound 2 has a moderate activity against human tumor cell lines MGC-803 with an IC50 value of 23.0 μg/mL.
