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421.
高效液相色谱法测定银杏叶提取物中槲皮素的含量 总被引:26,自引:1,他引:26
An HPLC method has been developed for the determination of quercetin,one of flavones,in extract ofGinkgo b1loba L,leaves.Quercetin was separated completely on a Zorbax-ODS column, 250mm× 4. 6mm i.d.,using a mixture of methanol, water and phosphoric acid(55:44. 6:0.4)as mobile phase; with UV detec-tion at 254nm. The results have shown that the recoveries were between 93.3~103.3%andCVwas l.4l%。 相似文献
422.
423.
HE Shan WU Bin SHI Hao SUN Cui-Rong② 《结构化学》2007,26(3):299-302
The title compound,(1α,6β,11β,14α)-1,7:6,20-diepoxy-6,11-dihydroxy-6,7-seco-ent-kaur-16-ene-7,15-dione-14-acetate (macrocalyxin J),is a diterpenoid which was isolated from the leaves of Rabdosia macrocalyx and characterized by single-crystal X-ray diffraction. It cry-stallizes in orthorhombic,space group P212121 with a=9.3608(8),b=14.9787(12),c=15.5750(13) ,Z=4,V=2183.8(3) 3,C22H30O9,Mr=438.46,Dc=1.334 g/m3,μ(MoKα)=0.103 mm1,F(000)=936,the final R=0.0532 and wR=0.1262 for 2252 observed reflections (I > 2σ(I)). In the molecule,three six-membered rings adopt chair,boat and slightly distorted boat conformations,respectively,while both five-membered rings have approximate envelope conformations. 相似文献
424.
水,旱稻品种叶片光谱的初步研究 总被引:1,自引:0,他引:1
彭运生 《光谱学与光谱分析》1998,18(3):269-272
本文研究了水,水旱稻叶片光谱特性,水旱稻在幼苗期,叶片的光谱特性在800-200nm波长区域基本相同,二者叶片叶绿素含量十分接近。 相似文献
425.
GC-MS联用分析三个品种杨梅树叶的挥发油组分 总被引:1,自引:0,他引:1
采用气相色谱-质谱联用技术对木叶、黑炭、东魁3个品种杨梅树叶中的挥发油进行分析比较.3种杨梅树叶挥发油中共检出14种相同成分,这些共有成分的相对含量分别占木叶梅叶、黑炭梅叶和东魁梅叶挥发油总相对含量的53. 3%、48. 4%、55. 15%.3种杨梅树叶挥发油中均舍有多种萜烯,对杨梅果实具有一定抗菌保鲜作用.东魁杨梅树叶挥发油萜烯含量最高,这可能是东魁杨梅果实保鲜期较长的原因;木叶杨梅叶含的特殊香味成分的含量较高,这可能是木叶梅果实香气最浓郁的原因. 相似文献
426.
427.
Summary The flavonoid content of olive leaves was studied by a method based on thin-layer chromatography and recording UV spectra directly on the layer. Three flavonoid glycosides, quercitrin, rutin and luteolin-7-glycoside, one flavonoid aglycone, luteolin, and chlorogenic acid were found in olive leaves. Three compounds with a biflavonoid-type sructure have been characterized. Ten cultivars were investigated in order to indicate qualitative and quantitative differences. 相似文献
428.
Muhammad Arif Khan Nafarizal Nayan Shadiullah Mohd Khairul Ahmad Soon Chin Fhong Muhammad Tahir Riyaz Ahmad Mohamed Ali Mohamed Sultan Mohamed Ali 《Molecules (Basel, Switzerland)》2021,26(9)
In this work, advanced nanoscale surface characterization of CuO Nanoflowers synthesized by controlled hydrothermal approach for significant enhancement of catalytic properties has been investigated. The CuO nanoflower samples were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high-resolution transmission electron microscopy (HR-TEM), selected-area electron diffraction (SAED), high-angular annular dark field scanning transmission electron microscopy (HAADF-STEM) with elemental mapping, energy dispersive spectroscopy (STEM-EDS) and UV–Vis spectroscopy techniques. The nanoscale analysis of the surface study of monodispersed individual CuO nanoflower confirmed the fine crystalline shaped morphology composed of ultrathin leaves, monoclinic structure and purified phase. The result of HR-TEM shows that the length of one ultrathin leaf of copper oxide nanoflower is about ~650–700 nm, base is about ~300.77 ± 30 nm and the average thickness of the tip of individual ultrathin leaf of copper oxide nanoflower is about ~10 ± 2 nm. Enhanced absorption of visible light ~850 nm and larger value of band gap energy (1.68 eV) have further supported that the as-grown material (CuO nanoflowers) is an active and well-designed surface morphology at the nanoscale level. Furthermore, significant enhancement of catalytic properties of copper oxide nanoflowers in the presence of for the degradation of methylene blue (MB) with efficiency ~96.7% after 170 min was obtained. The results showed that the superb catalytic performance of well-fabricated CuO nanoflowers can open a new way for substantial applications of dye removal from wastewater and environment fields. 相似文献
429.
黄树莓叶片中黄酮类物质的提取及抗氧化性 总被引:13,自引:1,他引:13
黄酮类物质具有降血糖、降血脂、抗心律失常、抗氧化高效性与低毒性、抗衰老等生理活性1 2 。从药食两种植物中筛选出高效低毒且经济的抗氧化性强的物质 ,必将是近一步开发天然高效食品抗氧化剂的重要途径[3 5] 。黄树莓是我国北方地区小浆果树种之一 ,其中以黑龙江分布较多。黄树莓的浆果甜而芳香 ,营养丰富 ,是鲜美的生食果品 ,也可加工制成果酱、果酒、果汁和蜜饯等。它又是密源植物和药用植物 ,有止渴、痰、发汗、活血的效用。本实验以测定黄树莓叶片总黄酮含量并考察了提取物粗黄酮对猪油的抗氧化性。1 实验部分1 1 主要试剂及仪… 相似文献
430.
Two new naturally occurring flavonoids, 3,4′,5,7-tetramethoxyflavone and 3,3′,4′,5,7-pentamethoxyflavone, along with known compounds, 5-hydroxy-3,4′,7-trimethoxyflavone, 5-hydroxy-3,3′,4,7-tetramethoxyflavone, ursolic acid, 2α,3α-dihydroxyurs-12-en-28-oic acid, phytosterols, and phytosteryl glucosides, have been isolated and characterized from the fresh leaves of Callicarpa formosana Rolfe. 相似文献