Taxus Cuspidata Research Articles

A rare 3,8-seco-taxane from the leaves of Taxus cuspidata

A rare 3,8-seco-taxane from the leaves of Taxus cuspidata

Studies on Taxol® biosynthesis. Preparation and tritium labeling of biosynthetic intermediates by deoxygenation of a taxadiene tetra‐acetate obtained from Japanese yew

Taxa-4(20),11(12)-diene-5α-acetate 5 and Taxa-4(20), 11(12)-diene-5α-acetate, 10β-ol 6, have been identified as early stage intermediates involved in the biosynthesis of Taxol® (paclitaxel). Tritium-labeled 5 and 6 were successfully prepared by Barton deoxygenation using tri-n-butyltintritiide of the C-14-hydroxyl group of a taxoid obtained from Japanese Yew.

ChemInform Abstract: Two New Taxoids from the Needles and Young Stems of Taxus cuspidata

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Biological Fingerprinting Analysis of Interaction Between Taxoids in Taxus and Microtubule Protein by Microdialysis Coupled with High-performance Liquid Chromatography/Mass Spectrometry for Screening Antimicrotubule Agents

Abstract Some natural products, such as traditional Chinese medicines(TCMs), contain compounds with anticanccr activity and have attracted a great interest in recent years as alternative anticanccr 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 microtubuics is reported. It was observed that the extract of Taxus contains at least five compounds which have affinity interaction with microtubuics 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 microlubulcs was also investigated.

ERK-like MAPK signaling and cytochrome c response to oleic acid in two-liquid-phase suspension cultures of Taxus cuspidata

To elucidate the underlying signal mechanisms of Taxus cuspidata in response to oleic acid (OA) in two-liquid-phase suspension cultures (TLPSCs), the mitogen-activated protein kinase (MAPK) activation and release of cytochrome c (CytC) from mitochondria in TLPSC T. cuspidata were investigated with Western blot. The results showed that a long-term treatment with 4% (v/v) OA caused apoptosis and release of CytC from mitochondria and inhibited the activation of extracellular signal-regulated kinase-like (ERK-like) MAPK (approximately 46 kDa) in TLPSC of T. cuspidata, but a short-term treatment significantly increased the ERK-like MAPK activity. These findings suggest that the coordinate expression of p-ERK and CytC is fundamentally involved in cell survival or death in TLPSC T. cuspidata. Further investigation confirmed that anthracene-9-carboxylate (an ion-channel blocker) and suramin (a G-protein inhibitor) markedly blocked the ERK-like MAPK activity, inhibited DNA ladder formation and O 2 − burst and reduced Taxol production. Although diphenyliodonium (an inhibitor of O 2 − formation) successfully blocked DNA ladder formation and decreased Taxol production, it did not significantly affect the ERK-like MAPK activity, indicating that the ERK-like MAPK activation should depend on the OA-stimulated G-protein and ion-channel activity, but not on the oxidative burst during the apoptosis and Taxol production in TLPSC T. cuspidata cells.

Variation in sexual reproduction in Taxus cuspidata Sieb. & Zucc

Male and female strobilus production and seed production were measured in multiple years in three natural populations of Taxus cuspidata in Japan. Our goal was to record variation in these parameters among individuals, among populations, and from year to year in this species, which is defined as dioecious. We also wished to determine whether cosexual individuals occurred in the sampled T. cuspidata populations. Male and female strobilus production varied significantly among male and female individuals, respectively, and individuals had significant annual variation in male and female strobilus production. Significant variation in male and female strobilus production was also recorded in comparisons among T. cuspidata populations. In some populations, males were significantly larger than females, but this result was not consistently observed. No cosexual individuals were recorded in any of the populations studied. Correlations among reproductive variables and measured vegetative characters were generally non-significant at all sites and in most years, with a few exceptions. When compared with other Taxus species, strobilus ratios in T. cuspidata were less male biased (2.3 male strobili per female strobilus in T. cuspidata versus 8.7 and 7.0 male strobili per female strobilus in Taxus brevifolia and Taxus canadensis, respectively). Seed production efficiency was comparable to T. brevifolia, but less than half of that recorded for T. canadensis, the only species of the genus that has individuals that are typically cosexual.

Seasonal changes of excitation energy transfer and thylakoid stacking in the evergreen tree Taxus cuspidata: How does it divert excess energy from photosynthetic reaction center?

Photosystems must efficiently dissipate absorbed light energy under freezing conditions. To clarify the energy dissipation mechanisms, we examined energy transfer and dissipation dynamics in needles of the evergreen plant Taxus cuspidata by time-resolved fluorescence spectroscopy. In summer and autumn, the energy transfer processes were similar to those reported in other higher plants. However, in winter needles, fluorescence lifetimes became shorter not only in PSII but also in PSI, indicating energy dissipation in winter needles. In addition, almost the same fluorescence spectra were obtained with different excitation wavelengths. In contrast, the fluorescence spectrum showed a large difference due to excitation wavelength in spring needles. The fluorescence spectrum of spring needles in 550-nm excitation showed similar spectra to that of winter needles, however, red-chlorophyll fluorescence was not observed in chlorophyll excitation. These observations suggest that some complexes with some kind of red-shifted carotenoid and red-chlorophyll unlink from the core complex in spring. Seasonal changes of excitation energy dynamics are also discussed in relation to changes in thylakoid stacking.

Two New Taxoids from the Needles and Young Stems of Taxus cuspidata

A new basic taxoid, taxine NA-13 (1) and a new neutral taxoid, 3α,11α-cyclotaxinine NN-2 (2) were isolated from Japanese yew tree, Taxus cuspidata. The structures of two new taxoids 1 and 2 were established as shown in structure 1 and structure 2 by spectroscopic analysis.

常緑針葉樹イチイ（Taxus cuspidata）におけるチラコイド膜貫通型光ストレス誘導性タンパク質one-helix proteins (Ohp)および stress-enhanced proteins (Sep)の解析

常緑針葉樹イチイ（Taxus cuspidata）におけるチラコイド膜貫通型光ストレス誘導性タンパク質one-helix proteins (Ohp)および stress-enhanced proteins (Sep)の解析

A taxane with a novel 9α,13α-oxygen bridge from Taxus cuspidata needles

A novel taxane with an unprecedented hemiacetal ring between C-13 and C-9 was isolated from the needles of Taxus cuspidata. The structure was characterized as (12αH)-2α,10β-diacetoxy-5α-cinnamoyloxy-9α,13α-epoxytax-4(20)-ene-11β,13β-diol ( 1). This is the first example of a natural taxane with a C-13 and C-9 oxygen bridge to form an unusual 6/8/6/6-membered ring system.

Lipidomic analysis reveals differential defense responses of Taxus cuspidata cells to two elicitors, methyl jasmonate and cerium (Ce 4+)

Methyl jasmonate (MeJA) and cerium (Ce 4+) elicitation share common features of increasing taxol accumulation of Taxus cuspidata cells. Interestingly, Ce 4+ induces programmed cell death (PCD), but this phenomenon is not observed with MeJA elicitation. Here, using a lipidomic approach to measure more than 100 membrane glycerophospholipids of T. cuspidata cells quantitatively, we discovered that lysophosphatidylcholine (LysoPC), phosphatidic acid (PA) and phosphatidylcholine were three potential lipid markers that were responsible for the differences between Ce 4+-induced cells and MeJA-induced cells. Compared with MeJA elicitation, marked increase of phospholipase D (PLD) activity was observed following Ce 4+ elicitation, suggesting that the PLD activation and high concentrations of PA production might mediate the PCD. Rapid increase of phospholipase A 2 (PLA 2) activity caused the release of fatty acids and LysoPC following Ce 4+ elicitation, which enhanced endogenous jasmonic acid (JA) accumulation. In contrast, PLA 2 activity was poorly induced following MeJA elicitation. PLA 2 inhibitor suppressed not only JA accumulation but also taxol production, suggesting that the PLA 2 activation mediated Ce 4+-induced taxol production partially through a JA-dependent signaling pathway. These results demonstrate that differential alternation of glycerolphospholipids caused by phospholipases constitutes an important step in cell death response to Ce 4+ and increasing taxol production.

Inhibition of 7,12‐Dimethylbenz[a]anthracene Induced Mouse Skin Carcinogenesis by Artemisia capillaris

Anticarcinogenic activity of medicinal herbs (Artemisia capillaris, Taxus cuspidata, Anthriscus sylveatris, and Curcuma longa) was examined for 7,12-dimethylbenz[a]anthracene (DMBA)-induced mouse skin carcinogenesis. Four types of solvent fractions (hexane, chloroform, ethyl acetate, and butanol) were prepared from the methanolic extract of medicinal herbs. The cytotoxicity and anticarcinogenic activities of solvent fractions were examined for mouse leukemia L1210 cancer cells and for female ICR mouse epidermal carcinogenesis induced by DMBA, respectively. The chloroform fraction of Artemisia capillaris, Taxus cuspidata, and Anthriscus sylveatris was more toxic to L1210 cells than other solvent fractions. The chloroform fraction of Artemisia capillaris markedly reduced the number of tumors/mouse and tumor incidence relative to that of other medicinal herbs tested. Major active chemical constituents in the chloroform fraction of Artemisia capillaries were found to be camphor, 1-borneol, coumarin, and achillin when analyzed by TLC and GC-MS. These results suggest that Artemisia capillaris was the most effective anticarcinogenic medicinal herb for DMBA-induced mouse epidermal carcinogenesis among 4 medicinal herbs tested, and the effect might be attributed to chemical compounds of camphor, 1-borneol, coumarin, and achillin.

Microbial Transformation of Cephalomannine by Luteibacter sp.

Luteibacter sp., a new bacterium isolated from the soil around a Taxus cuspidata Sieb. et Zucc plant, was studied for its capability to metabolize cephalomannine (1). After preparative fermentation, eight metabolites were obtained and characterized as baccatin III (2), baccatin V (3), 10-deacetylbaccatin III (4), 10-deacetyl-10-oxobaccatin V (5), 7-epicephalomannine (6), 10-deacetylcephalomannine (7), 10-deacetyl-7-epicephalomannine (8), and 3'-N-debenzoyl-3'-N-(2-methylbutyryl)-7-epitaxol (9). Among these metabolites, 9 is a new compound. Epimerization of the 7beta-OH group and hydrolysis of the C-13 side-chain were the two major reactions in this bioprocess. However, the biotransformation of 7beta-D-xylosyl-10-deacetyltaxol (10) with the same strain yielded a C-13 side-chain eliminated product without epimerization at C-7 (11). Metabolites 5-9 and 11, together with 1 and paclitaxel, were evaluated for their inhibitory activities against five human cancer cell lines (HCT-8, Bel-7402, BGC-823, A549, and A2780). All these compounds showed less potent activities than paclitaxel, which is currently used in clinical chemotherapy.

Molecular Cloning and Characterization of the Yew Gene Encoding Squalene Synthase from Taxus cuspidata

The enzyme squalene synthase (EC 2.5.1.21) catalyzes a reductive dimerization of two farnesyl diphosphate (FPP) molecules into squalene, a key precursor for the sterol and triterpene biosynthesis. A full-length cDNA encoding squalene synthase (designated as TcSqS) was isolated from Taxus cuspidata, a kind of important medicinal plants producing potent anti-cancer drug, taxol. The full-length cDNA of TcSqS was 1765 bp and contained a 1230 bp open reading frame (ORF) encoding a polypeptide of 409 amino acids. Bioinformatic analysis revealed that the deduced TcSqS protein had high similarity with other plant squalene synthases and a predicted crystal structure similar to other class I isoprenoid biosynthetic enzymes. Southern blot analysis revealed that there was one copy of TcSqS gene in the genome of T. cuspidata. Semiquantitative RT-PCR analysis and northern blotting analysis showed that TcSqS expressed constitutively in all tested tissues, with the highest expression in roots. The promoter region of TcSqS was also isolated by genomic walking and analysis showed that several cis-acting elements were present in the promoter region. The results of treatment experiments by different signaling components including methyl-jasmonate, salicylic acid and gibberellin revealed that the TcSqS expression level of treated cells had a prominent diversity to that of control, which was consistent with the prediction results of TcSqS promoter region in the PlantCARE database.

Expression of arabinogalactan proteins involved in Taxol production by immobilized Taxus cuspidata cells

The expression of arabinogalactan-proteins (AGPs), known as extracellular signal molecules, in immobilized T. cuspidata cells was investigated by immunofluorescence localization and Western blot analysis. It was found that the relative intensity of JIM13-reactive AGPs and Taxol production by T. cuspidata cells was increased 1.43-fold and 2.2-fold by immobilized cultures on day 25, respectively. Particularly, the expression levels of JIM13-reactive AGPs were much higher in the cells located in central and middle zones of the immobilized support matrices than these in the outer zone or in the suspension. Whether in immobilized T. cuspidata cells or in suspended T. cuspidata cells, the expression level of JIM13-reactive AGPs and Taxol production after two to three subcultures had no significant changes, but the immobilized cells always kept high-level expression of JIM13-reactive AGP and Taxol production during subcultures. Moreover, the enhancement of Taxol production was accompanied with a high-level expression of JIM13-reactive AGPs by T. cuspidata cells after treatment with 200 μM methyl jasmonate. Taken together, these results implicate that the AGPs in T. cuspidata cells may be taken as potential signal molecular involved in regulating the Taxol production by immobilized T. cuspidata cells.

Three New Taxanes with the 10-Alkoxy Group from the Heartwood ofTaxus cuspidata

Three novel taxanes with the 10-alkoxy group were isolated from heartwood of Taxus cuspidata. The structures were identified as 2alpha,14beta-diacetoxy-10beta-ethoxytaxa-11,4(20)-dien-5alpha-ol (1), 2alpha,14beta-diacetoxy-10beta-methoxytaxa-11,4(20)-dien-5alpha-ol (2), and 2alpha-acetoxy-10beta-ethoxytaxa-11,4(20)-diene-5alpha,14beta-diol (3) on the basis of spectroscopic analysis. These are the first taxanes with an alkoxy moiety on the skeleton.

Effect of Elicitors and a Biogenetic Precursor on Paclitaxel Production in Cell Suspension Cultures of Taxus cuspidata Var. nana

To stimulate the production of taxol (paclitaxel) by cell suspension cultures of Taxus cuspidata var. nana, two kinds of elicitors and a biogenetic precursor were used in F4G4 culture medium. Paclitaxel production was enhanced by each elicitor as well as by the biogenetic precursor and by a combination of the two elicitors or one elicitor and the biogenetic precursor. The amount ofpaclitaxel produced (16.6 mg L(-1)) was greatest when the cell suspension cultures were conducted in F4G4 medium containing chito-heptaose (8 mg L(-1)) and jasmonic acid (21 mg L(-1)). The productivity was enhanced 4.1 fold compared to the control. The amount of paclitaxel produced was increased by supplying air to the cultures, though the productivity depended on the amount of air supplied. However, no enhancement of production was observed when a combination of air and chito-heptaose was provided to the cell suspension cultures.

The Influence of UV Radiation on the Contents of Paclitaxel and Cephalomannine in the Fresh Leaves of Taxus cuspidata

The influence of UV wavelength, time of radiation and the processing method of sample on the content of paclitaxel and cephalomannine in the fresh leaves of Taxus cuspidata was studied in the article, in which two wavelength of 254 nm and 365 nm were used. The results showed that two kinds of UV radiation could enhance the content of two compounds in the fresh leaves of Taxus cuspidata by radiating the water homogenate of the fresh leaves. But, the increase trend of two compounds was different under diverse UV radiation. The wavelength of 365 nm made the content of two compounds achieve the maximum in 2 hours. And the rate of increase were 44.6% for paclitaxel and 53.0% for cephalomannine. While the wavelength of 254 nm needed 8 hours. The rate of increase were 39.2% for paclitaxel and 24.3% for cephalomannine. Thus,the content of paclitaxel and cephalomannine in the fresh leaves of Taxus cuspidata can be enhanced rapidly and effectively by radiating the water homogenate of the fresh leaves under UV radiation.

A METHOD FOR ESTIMATING FRACTAL DIMENSION OF TREE CROWNS FROM DIGITAL IMAGES

A new method for estimating fractal dimension of tree crowns from digital images is presented. Three species of trees, Japanese yew (Taxus cuspidata Sieb & Zucc), Hicks yew (Taxus × media), and eastern white pine (Pinus strobus L.), were studied. Fractal dimensions of Japanese yew and Hicks yew range from 2.26 to 2.70. Fractal dimension of eastern white pine range from 2.14 to 2.43. The difference in fractal dimension between Japanese yew and eastern white pine was statistically significant at 0.05 significance level as was the difference in fractal dimension between Hicks yew and eastern white pine. On average, the greater fractal dimensions of Japanese yew and Hicks yew were possibly related to uniform foliage distribution within their tree crowns. Therefore, fractal dimension may be useful for tree crown structure classification and for indexing tree images.

Photosynthetic activity in winter needles of the evergreen tree Taxus cuspidata at low temperatures

Photosystems harvest light energy, yet this energy cannot be efficiently employed for CO(2) assimilation at the below-freezing temperatures to which plants are typically exposed during winter in the temperate and boreal zones. To elucidate the mechanisms whereby this energy is dissipated, I evaluated performance of photosystems in winter needles of the evergreen tree Taxus cuspidata Sieb. et Zucc. Chloroplasts were localized adjacent to plasma membranes in needle cells in summer, whereas they congregated together in the centers of the cells during winter. When winter needles were acclimated to a temperature of 20 degrees C, their chloroplasts gradually dispersed to the edges of the cells, as in the summer. Acclimation-dependent relocalization coincided with changes in CO(2) uptake. Examination of photosystem II fluorescence kinetics in winter needles indicated that the quinone electron acceptor (Q(A)) reduction rate exceeded the Q(A) oxidation rate at low temperatures. The majority of Q(A) remained reduced even when winter needles were subjected to a temperature of -5 degrees C at low irradiance.