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21.
Isatis tinctoria and its indigo dyes have already provided highly active anti-leukaemic lead compounds, with the focus mainly being on indirubin, whereas indigo itself is inactive. There are many more indigoids to find in this plant extract, for example, quingdainone, an indigoid derived from tryptanthrin. We present here a new synthesis of hitherto neglected substituted quingdainones, which is very necessary due to their poor solubility behaviour, and a structure-dependent anti-leukaemic activity study of a number of compounds. Substituted α-phenylaminoacrylic acid was synthesised by hydrogen sulfide extrusion from an analogue mercaptoacetic acid, available from the condensation of rhodanin and a substituted tryptanthrin. It is shown that just improving water solubility does not increase anti-leukaemic activity, since a quingdainone carboxylic acid is inactive compared to dihydroxyquingdainone. The most effective compound, dihydroxyquingdainone with an AC50 of 7.5 µmole, is further characterised, revealing its ability to overcome multidrug resistance in leukaemia cells (Nalm-6/BeKa) with p-glycoprotein expression.  相似文献   
22.
Conditions were determined for the separation of a complex set of isoflavones and flavones (free aglycones, monoglucosides, diglucosides and esters) by HPLC-DAD UV and MS detection. A good separation of all analytes was obtained and satisfactory peak shapes were achieved by gradient elution on an RP C18 column. The method was then applied to carry out qualitative and quantitative analysis of bioflavonoids present in the herb and in vitro cultures of Genista tinctoria L. Electrospray ionisation mass spectrometry in the negative mode was used to identify individual flavonoids in G. tinctoria plant material. Photodiode array detection was also utilised in flavonoid characterisation. All flavonoid compounds were then quantified using an internal standard. The method developed is useful for monitoring the process of flavonoid biosynthesis in biomass obtained through in vitro cultures.  相似文献   
23.
Coreopsis tinctoria flowering (CTF) tops from the Kunlun Mountains in Xinjing (north-western China) have been used for tea production for about a century. This study was to assess antioxidant, nitrite-scavenging and N-nitrosamine inhibitory and antimicrobial activities of the essential oil extracted from CTF tops. The essential oil was extracted through hydrodistillation and its chemical compositions were analysed by GC–MS. Seventy compounds of the oil were identified, representing 81.87% of total oil. The antioxidant capacities of the oil with IC50 values for scavenging DPPH and ABTS were 287.66 ± 12.60 and 1.251 ± 0.127 μg mL? 1, respectively. The nitrite-scavenging and N-nitrosamine inhibitory activities (IC50) were 0.3912 ± 0.0127 and 0.6564 ± 0.036 μg mL? 1, respectively. The oil has a certain antimicrobial capacity, but its capacity was weaker than that of penicillinG (24 μg mL? 1). The oil showed antioxidant and antimicrobial capacities and had a stronger nitrite-scavenging and N-nitrosamine inhibitory properties.  相似文献   
24.
用制备的铜掺杂二氧化硅作为吸附剂, 富集雪菊提取液中的木犀草苷, 测量富集有目标组分吸附剂的近红外光谱, 所得光谱经预 处理后, 用偏最小二乘法建立木犀草苷的定量校正模型并进行验证. 结果表明: 当铜掺杂二氧化硅的用量为0.25 g、 常温振荡20 min时, 对木犀草苷吸附率达89.7%; 雪菊提取液中的木犀草苷经吸附剂富集后, 无需脱附可直接检测; 所得近红外光谱经多元散射校正结合一阶导数预处理后, 木犀草苷校正模型的预测质量浓度和参考质量浓度间的相关系数为0.975 0, 交叉验证均方根误差为0.959 8 mg/L, 木犀草苷在1.5~19.5 mg/L的较低质量浓度范围内, 预测集的回收率可达82.6%~111.4%.  相似文献   
25.
Abstract. Under projected changes in global climate, the growth and survival of existing forests will depend on their ability to adjust physiologically in response to environmental change. Quantifying their capacity to adjust and whether the response is species‐ or population‐specific is important to guide forest management strategies. New analyses of historic provenance tests data are yielding relevant insights about these responses. Yet, differences between the objectives used to design the experiments and current objectives impose limitations to what can be learned from them. Our objectives are (i) to discuss the possibilities and limitations of using such data to quantify growth responses to changes in climate and (ii) to present a modeling approach that creates a species‐ and population‐specific model. We illustrate the modeling approach for Larix occidentalis Nutt. We conclude that the reanalysis of historic provenance tests data can lead to the identification of species that have population‐specific growth responses to changes in climate, provide estimates of optimum transfer distance for populations and species, and provide estimates of growth changes under different climate change scenarios. Using mixed‐effects modeling techniques is a sound statistical approach to overcome some of the limitations of the data.  相似文献   
26.
27.
李博  唐秀娟 《科技信息》2009,(29):I0654-I0655
本文主要介绍了板兰根全草浸出液对含菌废水的杀菌效果,分析了板兰根的杀菌机理,并对药物质量、杀菌时间、废水pH值对杀菌效果的影响进行了研究,得出了最佳处理方案。实验表明,本杀菌方法杀菌率均在98%以上,且工艺简单,操作方便,不会产生二次污染。  相似文献   
28.
采用冷浸提取、超声波提取及索氏提取法研究了剑叶金鸡菊(Coreopsis lanceolata)不同器官总黄酮和总皂甙的含量.结果 表明,剑叶金鸡菊花总黄酮和总皂甙含量显著高于根、茎和叶的含量.超声波提取方法操作简便、快速,提取效率高,在粗提中显示明显的优势,利用该方法提取剑叶金鸡菊花总黄酮含量可达24.33 mg/g...  相似文献   
29.
Three new pregnane glycosides, tinctorosides A–C ( 1 – 3 , resp.), together with one known pregnane glycoside, stephanoside B ( 4 ), were isolated from the stems of Marsdenia tinctoria R. Br . (Asclepiadaceae). Their structures were elucidated by extensive spectral methods, especially 2D‐NMR experiments (1H,1H‐COSY, HSQC, HMBC, TOCSY, HSQC‐TOCSY, and ROESY), and chemical evidence.  相似文献   
30.
Coreopsis tinctoria flowering tops (CTFs) from the Kunlun Mountains in Xinjing (north-western China) have been used for tea production for about a century. This study aims to assess the antioxidant activities and total phenolic, flavonoid and proanthocyanidin contents of various solvent extracts of CTF. CTF was extracted using n-hexane, chloroform, ethyl acetate, n-butanol, 75% aqueous ethanol (AEE) and water. The antioxidant activities of the CTF extracts were investigated through DPPH, ABTS, *OH, *O2, total antioxidant capacity and reducing power assays. The results showed that n-butanol extract showed the highest contents of total phenols and flavonoids, with DPPH, ABTS and *OH radical-scavenging activities with IC50 values of 134, 90.72 and 13.8 μg mL? 1, respectively. The AEE demonstrated the strongest DPPH and ABTS radical-scavenging activities, with IC50 values of 103 and 75.16 μg mL? 1, respectively. Given its high antioxidant effect, CTF is a good source of natural antioxidants or functional food materials.  相似文献   
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