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排序方式: 共有104条查询结果,搜索用时 15 毫秒
1.
A New Bibenzyl Glycoside from Dendrobium moniliforme   总被引:1,自引:0,他引:1  
A new bibenzyl glycoside has been isolated from the stems of Dendrobium moniliforme (L.) Sw.(Orchidaceas).Its structure has been identified on the basis of spectroscopic and chemical methods.  相似文献   
2.
Two new compounds from Zingiber officinale   总被引:1,自引:0,他引:1  
A new cyclic diarylheptanoid,1,5-epoxy-3-hydroxy-1-(3-methoxy-4,5-dihydroxyphenyl)-7-(4-hydroxyphenyl)-heptane (1),as well as a new monoterpene,10-O-β-D-glucopyranosyl-hydroxy cineole (2) were isolated from the rhizomes of Zingiber officinale. The structures of compounds 1 and 2 were established based on their spectral data.In addition,the antioxidant activities of these compounds were also measured.  相似文献   
3.
Mycotoxigenic fungi have attracted special attention due to their threat to food security and toxicity to human health. Aqueous extract of Zingiber officinale Roscoe was used as reducing and capping agent for the synthesis of silver (AgNPs), copper (CuNPs), and zinc oxide (ZnONPs) nanoparticles. UV-Visible spectra of the AgNPs, CuNPs, and ZnONPs showed absorption peaks at λmax 416 nm, 472 nm, and 372 nm, respectively. Zeta potential of AgNPs, CuNPs, and ZnONPs were −30.9, −30.4 and −18.4 mV, respectively. ZnONPs showed the highest activity against Aspergillus awamori ZUJQ 965830.1 (ZOI 20.9 mm and MIC 24.7 µg/mL). TEM micrographs of ZnONPs-treated A. awamori showed cracks and pits in the cell wall, liquefaction of the cytoplasmic content, making it less electron-dense. The sporulation and ochratoxin A production of A. awamori was inhibited by ZnONPs in a concentration-dependent pattern. The inhibition percentage of OTA were 45.6, 84.78 and 95.65% for 10, 15, 20 of ZnONPs/mL, respectively.  相似文献   
4.
Abstract

The stems of Dendrobium huoshanense have long been used to prevent various diseases, including inflammatory diseases. This study was aimed to explain the anti-inflammatory effect of D. huoshanense stems in LPS-induced RAW 264.7 macrophages and to discover potential anti-inflammatory compounds. Results exhibited that D. huoshanense stems ethanol extract could significantly inhibit LPS-induced production of NO, TNF-α and IL-1β. Based on bioassay guided strategy, four bibenzyls (14) were isolated from D. huoshanense stems for the first time. Anti-inflammatory assay showed 14 could remarkably inhibit the production of NO in LPS-induced macrophages. Moreover, quantitative RT-PCR analysis displayed that the mRNA levels of iNOs, TNF-α and IL-1β could also be significantly reduced by 14. These results suggested that D. huoshanense stems ethanol extract and bibenzyls 14 might be well developed as therapeutic agent to prevent inflammatory diseases.  相似文献   
5.
杜芹芹  张旭  宋凤瑞  刘志强  刘淑莹 《应用化学》2010,27(10):1209-1214
采用高效液相色谱与电喷雾质谱联用技术(HPLC-ESI-MS),对不同质量比的人参与干姜或赤芍配伍过程中人参皂苷的变化进行了研究,发现随加入的干姜量增加,共煎液中的人参皂苷含量依次降低;少量的赤芍可以使各皂苷的溶出量增加;同时测定了人参单煎液、人参与干姜、赤芍共煎液中正丁醇提取物和水提物的抗氧化活性。 以抗坏血酸(500 μmol/L)作对照,人参与干姜、赤芍配伍溶液的抗氧化活性比人参单煎液要好,同时人参与干姜、赤芍共煎液中正丁醇提取物的FRAP(铁离子还原/抗氧化能力测定)值分别为1562.29和2969.78 μmol/L,高于人参与2种药单煎液(1260.27和2502.07 μmol/L)之和。  相似文献   
6.
Dendrobium officinale is an important medicinal plant in traditional Chinese medicine. The consumption of D. officinale has increased rapidly in recent years due to the health awareness among Chinese people. The present study aimed to determine trace elements levels in 42 D. officinale samples and to utilize the elemental data for identifying the cultivation technique. Eighteen trace elements (B, V, Cr, As, Mn, Fe, Mo, Cu, Zn, Se, Sr, Sn, Ti, Al, Co, As Pb, Cd, and Bi) were determined by inductively coupled plasma–mass spectrometry. Of the 11 essential elements, the mean concentrations ranged from 30.6?µg?kg?1 (Mo) in D. officinale with greenhouse cultivation to 161?mg?kg?1 (Fe) in D. officinale with rock cultivation, and the contributions of Mn may exceed the dietary reference intake value by the uptake of 20?g of D. officinale. Of the seven toxic elements, the mean concentrations ranged from 3.29?µg?kg?1 (Bi) in the D. officinale with greenhouse cultivation to 342?mg?kg?1 (Al) in the D. officinale with rock cultivation, and the contributions of Al may exceed the provisional tolerable daily intake value by the uptake of 20?g of D. officinale. The concentrations of seven metals (Bi, Pb, Fe, Al, Cr, As, and Mo) were utilized to identify the cultivation technique of the analyzed D. officinale samples through linear discriminant analysis.  相似文献   
7.
石斛是一种常用的中药材,经常使用新鲜的或干燥的茎条入药,有益胃生津、滋阴清热的效果。近年来,药理学研究探索出石斛具有抗白内障、抗氧化、抗肿瘤、提高免疫力的作用,其在许多病例中疗效显著,引起了国内外学者的关注,然而不同时间采集的石斛中氨基酸、微量元素等含量各不同,其对应药用价值,价格也不同,因此石斛价格等级分辨的研究具有重要意义。为快速鉴别不同价格、不同药效的石斛,研究了随机森林分类模型结合激光诱导击穿光谱技术(LIBS)对石斛价格等级进行分析建模。选取5个等级的石斛样品进行建模,为了对样品进行精确稳定分析,所有石斛样品均通过粉碎压片减小实验误差。采用1 064 nm波长的Nd∶YAG脉冲激光器作为激发光源,设置激光脉冲能量50 mJ,探测延时1μs,采集五个等级石斛样本的光谱数据,每个等级的样本采集40组光谱,共200组数据,并采用归一化处理,使所有的光谱数据转换到-1~1之间。采用归一化处理后的光谱数据进行主成分分析,通过主成分分析获得前7个主成分的得分矩阵,其累计解释95.24%的光谱信息。将选取的7个主成分作为输入,建立波段为220~880 nm的随机森林鉴别模型。并将石斛样本编号打乱,任意选取50%的光谱数据作为训练集,剩下50%的光谱数据作为测试集,默认决策树个数ntree为500,分裂属性集中属性个数mtry为5,建立模型对不同等级的石斛进行分类。等级一、二、三、四、五的识别率分别为95.45%, 100%, 78.26%, 94.12%和85%,平均识别率为90.57%。为提高识别率,研究了不同的ntree和mtry对分类模型的影响,利用袋外数据误差率估计对随机森林的两个参数进行了优化。选择ntree为300,mtry为1,等级一、二、三、四、五的识别率分别为100%, 100%, 92.31%, 100%和90%,平均识别率为96.46%,识别率提高了5.89%。综上所述,采用LIBS技术结合优化后的随机森林模型鉴别石斛等级具有一定的可行性,为未来快速鉴定不同价格的石斛等级分类提供了可行性的判别系统。  相似文献   
8.
It is generally believed that fresh Dendrobium officinale (FDO) has more significant pharmacological activity than dried Dendrobium officinale (DDO); however, the difference has not been clearly shown. Our study compared their antioxidant properties both in vitro and in vivo, and the molecular weight arrangement and monosaccharide composition of the fresh Dendrobium officinale polysaccharides (FDOPs) and the dried Dendrobium officinale polysaccharides (DDOPs) were analyzed by HPLC-GPC and GC-MS. The results showed that the FDO and its polysaccharides had more significant effects on scavenging DPPH, ABTS, and hydroxyl radicals than the DDO. In addition, both the FDO and DDO significantly reduced lipid peroxidation levels and increased the SOD, T-AOC, CAT, and GSH levels in mice with acute liver damage caused by CCl4, while the FDO and its polysaccharides were more effective. Histopathological analysis further verified the protective effect of the Dendrobium polysaccharides on CCl4-induced liver injury. The determination of the polysaccharides revealed that the polysaccharide and mannose contents of the FDO were significantly higher than their dried counterparts, and the homogeneous arrangement of the polysaccharides in the FDO was degraded into three polysaccharide fragments of different molecular weights in the DDO. Overall, our data identified differences in the antioxidant activities of the FDO and DDO, as well as the reasons for these differences.  相似文献   
9.
A new Dendrobine-Type Alkaloid from Dendrobium nobile   总被引:1,自引:0,他引:1  
A new dendrobine-type alkaloid has been isolated from stems of Dendrobium nobile lindl.Its structure has been identified on the basis of spectroscopic method.  相似文献   
10.
A new method of extracting essential oils from dried plant materials has been studied. By adding a microwave-absorption medium (MAM) to a reactor, solvent-free microwave extraction (SFME) was improved and can be used to extract essential oils from dried plant material without pretreatment. With a microwave irradiation power of 85 W it took only approximately 30 min to extract the essential oils completely. The whole extraction process is simple, rapid, and economical. Three types of MAM, iron carbonyl powder (ICP), graphite powder (GP), and activated carbon powder (ACP), and two types of dried plant material, Illicium verum Hook. f. and Zingiber officinale Rosc., were studied. The results were compared with those obtained by use of conventional SFME, microwave-assisted hydrodistillation (MAHD), and conventional hydrodistillation (HD), and the conclusion drawn was that improved SFME was a feasible means of extracting essential oils from dried plant materials, because there were few differences between the composition of the essential oils extracted by improved SFME and by the other methods.  相似文献   
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