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21.
Ren Xu Ming‐Zi Wang Chun‐Hua Lu Zhong‐Hui Zheng Yue‐Mao Shen 《Helvetica chimica acta》2009,92(8):1514-1519
Three new sesquiterpenes, tuberculariols A–C ( 1 – 3 , resp.), were isolated from the mutant strain M‐741 of Tubercularia sp. TF5, an endophytic fungus of Taxus mairei. Their structures were elucidated by spectroscopic analyses including 1D‐ and 2D‐NMR experiments, and HR‐Q‐TOF‐MS. Antitumor and antibacterial properties of these compounds were evaluated. 相似文献
22.
A large‐scale separation of paclitaxel from semi‐purified bark extract of Taxus yunnanesis was investigated. The chromatographic behavior of paclitaxel and two dose editing analogues, cephalomannine and 7‐epi‐10‐deacetyltaxol were systematically studied on a C18 bonded phase column with different mobile phase in reverse phase mode. According to the notably different selectivity of the methanol and acetonitrile with water in the mobile phase and the most important requirement of capacity in preparative chromatography, the optimum suitably mobile phase used in a large‐scale isolation of paclitaxel and 7‐epi‐10‐deacetyltaxol on a preparative C18 column was given. Cephalomannine was eliminated by ozonolysis and after then separated throughout a normal phase silica column. The whole large‐scale process for high purity paclitaxel from the bark extract of Taxus yunnanesis consisted of a preliminary purification with Biotage FLASH 150i system based on a prepacked normal phase silica cartridge followed by using a C18 Nova‐pak? column in Waters PrepLC? 4000 preparative HPLC system. The structure of 7‐epi‐10‐deacetyltaxol was elucidated by 2D NMR technologies of TOCSY, DQF‐COSY, HMQC and HMBC, etc. 相似文献
23.
Rui Sun Kusng Fu Yujie Fu Yuangang Zu Ying Wang Meng Luo Shuangming Li Hao Luo Zhengnan Li 《Journal of separation science》2009,32(9):1284-1293
An environment‐friendly method was established for the preparative separation and enrichment of four taxoids, namely 10‐deacetylbaccatin III (10‐DAB III), 7‐xylosyl‐10‐deacetyltaxol (7‐xyl‐10‐DAT), cephalomannine and paclitaxel from Taxus chinensis needles extracts. Characteristics of seven widely used macroporous resins for four taxoids were compared, AB‐8 resin offered better adsorption and desorption capacities than others. AB‐8 resin column chromatography was used to study the desorption process for four taxoids. The optimum parameters for desorption were 30% ethanol 5 RV for removing impurities, following 15 RV for 10‐DAB III, after the desorption of impurities with 35% ethanol 10 RV, 45% ethanol 30 RV for 7‐xyl‐10‐DAT, then 65% ethanol 10 RV for cephalomannine and paclitaxel, the flow rate was 6 RV/h. After separation on AB‐8 resin column chromatography, the contents of 10‐DAB III, 7‐xyl‐10‐DAT, cephalomannine and paclitaxel in the product reached 4.58, 13.17, 1.36 and 3.08%, respectively, which were 7.63‐, 3.68‐, 6.18‐ and 6.55‐fold to those in T. chinensis needles extracts. The recovery yields were 94.96, 77.32, 88.09 and 95.25%. In general, the AB‐8 resin column chromatography has the advantages of lower cost, high efficiency and simple procedure. Therefore, it may provide scientific references for the preparative separation and enrichment of taxoids from other T. species. 相似文献
24.
Two-liquid-phase plant cell cultures employ the use of a partitioning system to redirect extracellular product into a second
phase. After the addition of organic solvent, in order to understand the defense system of Taxus cuspidata cells to organic solvent in two-liquid-phase suspension cultures, we investigated cells' antioxidant metabolism. The results
showed that T. cuspidata cells responded to oleic acid with oxidative bursts in both intracellular H2O2 and extracellular O2
− production. Inhibition studies with diphenylene iodonium suggested that the key enzyme responsible for oxidative bursts was
primarily NADPH oxidase. Investigation of the relationship between reactive oxygen species (ROS) and defense responses induced
by oleic acid indicated that 4% (v/v) oleic acid increased the levels of antioxidant enzymes of superoxide dismutase, ascorbate
peroxidase, and catalase and the antioxidant capacity of reduced ascorbate and glutathione. However, when oleic acid content
reached a critical value (6% [v/v]), no further increase in antioxidant enzymes and antioxidant capacity was observed, indicating
that the defense responses played a role in a certain range of oleic acid content, beyond which the overall ROS scavenging
machinery was not induced and the peroxidation of membrane lipids emerged. 相似文献
25.
Some natural products, such as traditional Chinese medicines(TCMs), contain compounds with anticancer activity and have attracted a great interest in recent years as alternative anticancer therapies. A quick and convenient assay for screening antimicrotubule compounds in which in vitro microdialysis/high-performance liquid chromatography (HPLC) is used to monitor the binding of the compounds extracted from TCM Taxus cuspidata Siebold & Zucc(Taxus) to microtubules is reported. It was observed that the extract of Taxus contains at least five compounds which have affinity interaction with microtubules by biological fingerprinting analysis, and they were identified as the taxoids of taxol, baccatin III, 10-deacetylbaccatin Ⅲ(10-DAB), cephalomannine and 7-epi-10-deacetyltaxol (7-epi-10-DAT) based on the comparison of their high-performance liquid chromatographic/mass spectrometric and UV spectra with those of the standard samples, both assembly-promoting and disassembly-inhibiting characteristics of those compounds were evaluated. It was observed that baccatin Ⅲ and 10-DAB bound to microtubules and the binding degrees were influenced by GTP. Competitive binding behavior of taxol with other four taxoids to microtubules was also investigated. 相似文献
26.
Lingyu Li Yiming Chen Yingli Ma Zhong Wang Tao Wang Yinfeng Xie 《Molecules (Basel, Switzerland)》2021,26(18)
Taxus mairei is an important source for industrial extraction of taxol in China. However, the standard and steps of extraction are currently not uniform, which seriously affects the taxol yield. In the present study, the influence of four factors (methanol concentration, solid-liquid ratio, ultrasonic extraction temperature, and ultrasonic extraction time) on the taxol yield was successively explored in T. mairei. A response surface methodology (RSM) was used to optimize the extraction process based on the single-factor experiments above. The optimal conditions were as follows: methanol concentration was 90%, solid-liquid ratio was 1:15 (g/mL), ultrasonic extraction temperature was 40 °C and ultrasonic extraction time was 60 min. Moreover, the twigs and needles from T. mairei with different tree ages were treated by the optimum extraction process, which further revealed temporal and spatial distribution of taxol in the reproducible tissues. Interestingly, the taxol content was relatively higher in needles of T. ‘Jinxishan’ (a cultivar from T. mairei with yellow aril, FY), but was less in FY twigs. The accumulation of taxol in twigs and leaves of females (with red aril, FR) was significantly higher than that of males (M); however, the content showed a decreasing trend with the increasing tree ages. Therefore, it is suitable to increase the proportion of female trees especially the FY leaves as raw materials for the industrial production of taxol from T. mairei, and the tree ages should be better controlled at 3–7 years. 相似文献
27.
The phytochemical investigation on the ethanolic extracts of the barks of Taxus yunnanensis (Taxaceae) led to the isolation of two new neo-lignans, named taxuyunins A (1) and B (2), along with the known diterpenolignan, brevitaxin (3). Their structures were elucidated on the basis of spectroscopic and chemical evidences. Compound 1 is a neo-lignan xyloside while compound 2 belongs to the rare neo-lignan possessing a ramified C3 side chain. 相似文献
28.
Reactive oxygen species, cell growth, and taxol production of Taxus cuspidata cells immobilized on polyurethane foam 总被引:1,自引:0,他引:1
Dynamic changes in reactive oxygen species (ROS) of Taxus cuspidata cells immobilized on polyurethane foam were investigated and the relation between ROS content and taxol production was discussed.
Immobilization shortened the lag period of cell growth and moderately increased H2O2 and O2
−• contents inside the microenvironment within the first 15 d. After 20 d, excessive production of H2O2 and O2
−• was observed accompanied by marked increases in membrane lipid peroxidation and cell membrane permeability. The taxol content
of immobilized cells was fourfold that of suspended cells at d 35. The addition of exogenous H2O2 barely affected malondialdehyde content and cell membrane permeability but led to an obvious accumulation of taxol. It is
inferred that the intracellular and extracellular H2O2 inside the microenvironment might be one factor promoting taxol biosynthesis under the immobilization stress. 相似文献
29.
Kai Zhang Yong Li Zhi‐Yi Ni Man‐Li Zhang Yu‐Fang Wang Qing‐Wen Shi Chang‐Hong Huo Françoise Sauriol Hiromasa Kiyota Yu‐Cheng Gu Mei Dong 《Helvetica chimica acta》2012,95(9):1566-1572
Two new natural taxanes were isolated from the heartwood of Taxus cuspidata. The structures were established as rel‐(2α,5α,7β,9α,10β,12α)‐7,9‐bis(acetyloxy)‐2‐(benzoyloxy)‐11,12‐epoxy‐1,5‐dihydroxy‐10‐[(hydroxyacetyl)oxy]tax‐4(20)‐en‐13‐one ( 1 ), and (2α,5α,10β,14β)‐taxa‐4(20),11‐diene‐2,5,10,14‐tetrol 2‐acetate ( 2 ) on the basis of spectroscopic analysis. 相似文献
30.
Mathieu Paoli Ange Bighelli Vincent Castola Félix Tomi Joseph Casanova 《Magnetic resonance in chemistry : MRC》2013,51(11):756-761
In the course of our ongoing work on the chemical characterization of Taxus baccata L. growing wild in Corsica, we have developed and validated a method for direct quantification of taxane derivatives by 13C NMR using 10‐deacetylbaccatin III as reference compound and 1,6‐hexanediol as internal standard. We have observed good accuracy (relative errors between 0.3% and 3.5%), linearity (R2 = 0.999) and precision (reproducibility 8.5 mg ± 1.1%) of the measurements. The experimental procedure was applied to the quantification of six identified taxanes in a fraction of chromatography of a methanol extract of T. baccata leaves. This method can be applied to other compounds bearing the taxane skeleton. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献