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PubMedDate not supplied

Taxus spp. needles contain amounts of taxol comparable to the bark of Taxus brevifolia: analysis and isolation.

New sources for the antitumor natural product taxol [1] are needed as demands for this promising cancer chemotherapeutic agent increase. Presently, supplies of taxol for clinical studies are obtained from the bark of Taxus brevifolia, a potentially limited source. Using analytical methods, the needles and stems of six Taxus species have been examined for taxol [1] and 10-deacetylbaccatin III [5], a related compound that can be converted to taxol through a semi-synthetic route. Amounts of taxol comparable to quantities reported from the bark of T. brevifolia were found in the needles of four of the Taxus species investigated. In addition, taxol was isolated from the needles of one Taxus species. Thus, Taxus needles may provide a renewable source of this valuable compound.

Alkaloids↗
PubMed2000

Taxane diterpenoids from Taxus yunnanensis and Taxus cuspidata.

Chemical examination of the seeds of the Chinese yew, Taxus runnanensis Cheng et L. K. Fu and the Japanese yew, Taxus cuspidata Sieb et Zucc, resulted in the isolation of four taxane diterpenoids. The structures of these taxoids were established as (12alpha)-2alpha-acetoxy-5alpha,9alpha, 10beta-trihydroxy-3,11-cyclotax-4(20)-en-13-one; 2alpha,7beta,13alpha-triacetoxy-5alpha, 9alpha-dihydroxy-2(3-->20)abeotaxa-4(20),11-dien-10-one; 9alpha,10beta-diacetoxy-5alpha-cinnamoyloxytaxa- 4(20),11-dien-13alpha-ol and the known 2alpha,7beta,9alpha,10beta,13-pentaacetoxytax a-4(20),12-diene-5alpha,11beta-diol on the basis of spectral analysis.

Diterpenes↗
PubMed1999

Six new taxane diterpenoids from the seeds of taxus chinensis var. mairei and taxus yunnanensis

Six new taxane diterpenoids and three known 2(3-->20)abeotaxoids were isolated from the seeds of Taxus chinensis var. mairei and of Taxus yunnanensis. Their structures were established as 2alpha, 20-dihydroxy-9alpha-acetoxytaxa-4(20),11-dien-13-one (1), 5alpha-cinnamoyloxy-7beta,10beta, 13alpha-triacetoxy-2(3-->20)abeotaxa-2alpha-ol-4(20),11-dien-9-one (2), 5alpha-cinnamoyloxy-10beta, 13alpha-diacetoxy-2(3-->20)abeotaxa-2alpha,7beta-diol-4(20), 11-dien-9-one (3), 5alpha-cinnamoyloxy-2alpha,7beta,10beta, 13alpha-tetraacetoxy-2(3-->20)abeotaxa-4(20),11-dien-9-one (4), 7-O-acetyltaxine A (5), 2alpha,7beta,10beta, 13alpha-tetraacetoxy-5alpha-phenylisoserinatoxy-2(3-->20)abeotaxa-4(2 0),11-dien-9-one (6), 5-O-acetyltaxinine M (7), 5alpha-hydroxy-2alpha,7beta,10beta, 13alpha-tetraacetoxy-2(3-->20)abeotaxa-4(20),11-dien-9-one (8), and 2alpha,5alpha-dihydroxy-7beta,10beta, 13alpha-triacetoxy-2(3-->20)abeotaxa-4(20),11-dien-9-one (9), on the basis of 1D and 2D NMR spectroscopic analysis. Compound 1, as a new compound isolated from T. chinensis var. mairei, is a rare example of a taxane with a 4,11-diene unit, which is considered to be an important intermediate in the biogenesis of taxoids. Compounds 2-4, 6, and 7 are new compounds, isolated from T. yunnanensis, which also afforded the known compounds 5, 8, and 9.

Journal Article↗
PubMed1996

Taxol production in nodule cultures of Taxus.

The in vitro synthesis of secondary compounds from plants is one source of scarce and valuable phytopharmaceuticals. Often, some level of cellular or tissue differentiation is needed for the biosynthesis of many of these important compounds. Nodule cultures, consisting of cohesive multicellular units displaying a high degree of differentiation, were initiated from cultured needles of seven Taxus cultivars (Taxus cuspidata, Taxus x media 'Hicksii', Taxus x hunnewelliana 'Richard Horsey', Taxus x media 'Dark Green Spreader', Taxus x media 'L. C. Bobbick', and Taxus brevifolia). Under normal semicontinuous perfusion culture conditions (bimonthly refreshments to yield 0.2% sucrose), only trace amounts of taxol were detected from Taxus nodule cultures. However, with an elevated sucrose level (0.5% or 1.0%), taxol production was enhanced in T. cuspidata nodules to approximately 12 micrograms taxol/g nodule dry weight (dw). Stimulation of taxol production by elevated sucrose levels occurred even in the absence of other nutrients. The effect of increased sucrose on taxol induction does not appear to be due to an osmotic effect in the medium, suggesting that the increase in taxol production may be correlated with a metabolic process within the nodules. Although sucrose had a significant effect on taxol production, taxane precursors or elicitors of terpenes, as well as other plant secondary metabolites, had no effect on the production of taxol from these cultures. In addition to taxol, the higher sucrose levels also induced the production of 7-epi-10-deacetyltaxol, cephalomannine, and 7-epi-10-deacetylcephalomannine, so that total content of these taxanes equaled approximately 39 micrograms taxane/g dw nodules.

Culture Media↗
PubMed2000

Cell lines of Taxus species as source of the anticancer drug taxol.

Callus culture of Taxus baccata and Taxus x Media were induced using explants of young stems and female gametophyte. Culture conditions have been established for the cell suspension of the different callus cell lines. Callus were induced from Taxus baccata and Taxus x Media using Murashige and Skoog (MS) medium supplemented with different concentrations of 2,4 D (2,4-dichlorophenoxyacetic) and benzylaminopurine (BA). All the cultures grew slowly following the first subculture and the majority turned brown and ceased growth. The fast growing callus lines constituted a habituated callus lines (CFGTB; CFGTM; CSTB and CSTB). These callus lines were used to induce cell suspension in the best nutritional medium (1 mg/l 2,4-D and 0.1 mg/l BA). The callus exhibited levels of taxol ranging from 0.1 to 15 mg/Kg on a dry weight basis. Suspension cultures of Taxus baccata (CSTB and CFGTB) and Taxus x Media (CSTM and CFGTM) were maintained at 25 degrees C on a MS medium with two weeks transfers. The maximum taxol production for suspension cell was within the range 5 to 6 mg/l.

Antineoplastic Agents↗
PubMed1992

Sudden unexpected death due to Taxus poisoning. A report of five cases, with review of the literature.

The toxicity of yew (Taxus) has been known since antiquity. However, in the past 31 years, to our knowledge only six cases of Taxus poisoning have been reported in the literature. In the present paper we add five cases. From a forensic point of view, intoxication with Taxus has three important aspects: (i) the clinical presentation, which among other causes should suggest Taxus intoxication; (ii) the fact that the diagnosis may often be easily made by examination of the contents of stomach, duodenum and small bowel and (iii) the widespread availability in the near future of Taxol, an anti-neoplastic drug which is an alkaloid extracted from Taxus. The clinical and autopsy findings are summarized, the diagnostic aspects are discussed and the literature concerning Taxus is reviewed.

Adult↗
PubMed1996

Methyl jasmonate-induced overproduction of paclitaxel and baccatin III in Taxus cell suspension cultures.

Taxus cell culture may be an alternative source of paclitaxel and related taxane production. Significantly increased amounts of paclitaxel and baccatin III were observed in cultured cells of Taxus species after exposure to methyl jasmonate. Among the three species of Taxus tested, Taxus media showed the highest paclitaxel content while Taxus baccata showed the highest baccatin III content when 100 microM of methyl jasmonate was added to the culture media. Furthermore, the activities of methyl jasmonate and related substances for inducing paclitaxel production were compared in cell suspension cultures of T. media. Methyl jasmonate and its free acid showed the strongest promoting activity. Reduction of the keto group at the C-3 position greatly reduced this activity. cis-Jasmone, which does not have a carboxyl group at the C-1 position, had almost no activity. These results suggest that these two regions of methyl jasmonate are important for promoting the production of paclitaxel and related taxanes in Taxus cell cultures.

Acetates↗
PubMed1996

Taxol content of various Taxus species in Hungary.

The anticancer drug taxol was separated and quantitatively determined in bark and foliage of different Taxus species by high-performance liquid chromatography to prove the presence of taxol in Hungarian Taxus species. The measurements were carried out with photodiode array detection using a porous graphitized carbon column, and a water:dioxan 54:46 v/v eluent. Taxol was established as being present in measurable amounts in each Hungarian Taxus species. According to the results bark was richer in taxol than foliage. It could also be observed that the older the bark or foliage, the more taxol it contained. The validation process proved that the method is reliable and can be used for the separation and quantitative determination of taxol in both the bark and foliage of Taxus species grown in Hungary.

Antineoplastic Agents, Phytogenic↗
PubMed1994

Immunological detection and quantitation of 10-deacetylbaccatin III in Taxus sp. plant and tissue cultures.

A high-sensitive ELISA method was developed for the detection and semi-quantitative determination of 10-deacetylbaccatin III and its structurally related compounds in crude extract of Taxus sp. plants and tissue cultures. The antibodies were raised in rabbits using 7- or 10-succinyl-10-deacetylbaccatin III-BSA conjugate as immunogen. The working range of the assay was from 0.003 to 1.000 ng (0.09 to 31.33 nM) of 10-deacetylbaccatin III per assay. The cross-reacting material in crude plant extract was examined by chromatographic (silica gel CC, HPLC) and immunoassay methods. Study on the evaluation of cross-reacting material in crude Taxus plant extracts showed that at least 80% of the immunosignal correspond to 10-deacetylbaccatin III in the extract. The ELISA method was applied to investigate the 10-deacetylbaccatin III equivalent content in crude extracts of 19 plants species including Taxaceae, Taxodiaceae and Pinaceae species. The 10-deacetylbaccatin III-like structure was only detected in Taxus and Torreya sp. The results indicate that this immunoassay is a useful tool for the rapid screening of species, varieties or individual plants out of a wide population. The distribution of 10-deacetylbaccatin III equivalent content in 9-month old Taxus plantlets cultivated in vitro as well as in callus culture was investigated.

Antibody Specificity↗
PubMed2000

[Study on taxol release in the two-liquid-phase cultures of Taxus cuspidata].

Effects of rare earth compound (ammonium sulphate), organic solvents(oleic acid and dibutylphthalate) and the integrated function of the rare earth compound and organic solvents were studied on taxol release in the Taxus cuspidata suspension cultures. And then effects of different organic solvents(paraffin, organic acid, alcohol and ester), their volumetric fraction and phase toxicity were studied on taxol release in the two-liquid-phase cultures of Taxus cuspidata. The results showed that the addition of the rare earth compound or the organic solvents could strengthen obviously taxol release, especially the organic solvents. But the addition of the rare earth compound could not strengthen further taxol release in the twoliquid-phase cultures of Taxus cuspidata. Therefore the organic solvents were very good permeabilizing reagents, which could enhance obviously secondary metabolite in the twoliquid-phase cultures of plant cells. Release percentage of taxol was increased into more than 75% from 40% of the control.

Antineoplastic Agents, Phytogenic↗
PubMed1994

Profiling taxanes in Taxus extracts using lc/ms and lc/ms/ms techniques.

Analytical methodology developed for the trace analysis of natural products in crude extracts was utilized for the rapid and systematic structure elucidation of taxanes in Taxus extracts and process intermediates. This method integrates analytical hplc, uv detection, uv spectroscopy, full-scan ionspray mass spectrometry and tandem mass spectrometry on-line. The identification of structure of a taxane is based on comparing the mass spectrometric characteristics of the taxane with the paclitaxel substructural "template." Analytical data for taxanes in preparations from Taxus brevifolia and Taxus baccata were observed, including chromatographic characteristics using a standard hplc system, molecular weight, and collision induced dissociation (cid) tandem mass spectrometry (ms/ms) product ion spectra. The data obtained for 18 taxanes from natural sources using this method provided a taxane profile database useful for the rapid identification of taxanes in mixtures and samples of limited quantity.

Bridged Bicyclo Compounds↗
PubMed1999

Isolation of labeled 9-dihydrobaccatin III and related taxoids from cell cultures of taxuscell cultures of taxus canadensis elicited with m.

Cell suspension cultures of Taxus canadensis rapidly produced paclitaxel (1) and other taxoids in response to elicitation with methyl jasmonate. Three of these taxoids, of potential value in the synthesis of taxoid analogues, have been isolated from cell cultures of Taxus canadensis and identified as 13-acetyl-9-dihydrobaccatin III (2), baccatin VI (3), and 9-dihydrobaccatin III (4). Of these metabolites, 9-dihydrobaccatin III (4) has not been isolated from any Taxus species, whereas 13-acetyl-9-dihydrobaccatin III (2) and baccatin VI (3) have been isolated from a number of natural sources. 2D NMR techniques, mass spectrometry, and partial synthesis were used to rigorously elucidate the structure and stereochemistry of these natural products.

Acetates↗
PubMed2000

Molecular cloning of a 10-deacetylbaccatin III-10-O-acetyl transferase cDNA from Taxus and functional expression in Escherichia coli.

The cDNA clone for a 10-deacetylbaccatin III-10-O-acetyl transferase, which catalyzes formation of the last diterpene intermediate in the Taxol biosynthetic pathway, has been isolated from Taxus cuspidata. By using consensus sequences from an assembly of transacylases of plant origin and from many deduced proteins of unknown function, a homology-based PCR cloning strategy was employed to amplify initially a 911-bp gene fragment of the putative taxane C-10 hydroxyl acetyl transferase from Taxus. This amplicon was used to screen a cDNA library constructed from mRNA isolated from methyl jasmonate-induced Taxus cells, from which the full-length 10-deacetylbaccatin III-10-O-transacetylase sequence was obtained. Expression of the ORF from pCWori(+) in Escherichia coli JM109 afforded a functional enzyme, as determined by (1)H-NMR and MS verification of the product baccatin III derived from 10-deacetylbaccatin III and acetyl CoA. The full-length cDNA has an ORF of 1,320 bp corresponding to a deduced protein of 440 residues with a calculated molecular weight of 49,052, consistent with the size of the operationally soluble, monomeric, native acetyl transferase. The recombinant acetyl transferase has a pH optimum of 7.5, has K(m) values of 10 microM and 8 microM for 10-deacetylbaccatin III and acetyl CoA, respectively, and is apparently regiospecific toward the 10-hydroxyl group of the taxane ring. Amino acid sequence comparison of 10-deacetylbaccatin III-10-O-acetyl transferase with taxadienol-5-O-acetyl transferase and with other known acyl transferases of plant origin indicates a significant degree of similarity between these enzymes (80% and 64-67%, respectively).

Acetyltransferases↗
PubMed2000

Molecular cloning of a taxa-4(20),11(12)-dien-5alpha-ol-O-acetyl transferase cDNA from Taxus and functional expression in Escherichia coli.

The taxa-4(20),11(12)-dien-5alpha-ol-O-acetyl transferase which catalyzes the third step of Taxol biosynthesis has been isolated from methyl jasmonate-induced Taxus cells, and partially purified and characterized (K. Walker, R. E. B. Ketchum, M. Hezari, D. Gatfield, M. Golenowski, A. Barthol, and R. Croteau, Arch. Biochem. Biophys. 364, 273-279 1999). A revised purification method allowed internal amino acid microsequencing of the enzyme, from which primers were designed and employed to amplify a transacetylase gene-specific fragment. This radiolabeled, 900-bp amplicon was used as a hybridization probe to screen a cDNA library constructed from poly(A)(+) RNA isolated from induced Taxus cells, from which a full-length transacetylase sequence was obtained. Expression of this clone from pCWori(+) in Escherichia coli JM109 cells yielded the functional enzyme, as determined by radiochemical assay and combined capillary gas chromatographic-mass spectrometric verification of the acetylated product. The full-length DNA has an open-reading frame of 1317 nucleotides corresponding to a deduced amino acid sequence of 439 residues that exhibits high sequence identity to the proteolytic fragments of the native enzyme, which the recombinant transacetylase resembles in properties. Consistent with the size of the operationally soluble native enzyme, the DNA appears to encode a monomeric protein of molecular weight 49,079 that bears no N-terminal organellar targeting information. Sequence comparison of the taxadien-5alpha-ol-O-acetyl transferase with the few other known acyl transferases of plant origin indicates a significant degree of similarity between these enzymes (64-67%). The efficient conversion of taxadien-5alpha-yl acetate to further hydroxylated intermediates of the Taxol pathway confirms the significance of this acylation step and suggests this taxadienol transacetylase to be an important target for genetic manipulation to improve Taxol production.

Acetyltransferases↗
PubMed2001

Stimulation of taxol production and excretion in Taxus spp cell cultures by rare earth chemical lanthanum.

The trivalent ion of a rare earth element, lanthanum, was tested for elicitor-like effects on taxol production in suspension cultures of four different Taxus spp cells. In T. yunnanensis cell cultures, the lanthanum ion at concentrations from 1.15 to 23.0 microM stimulated taxol production. The lanthanum ion also promoted taxol excretion by the T. yunnanensis cells considerably. The maximum stimulation of taxol production was achieved by the addition of 5.8 microM La3+ to the culture during mid-log growth phase, increasing the volumetric taxol yield by nearly threefold, from 2.61+/-0.37 to 9.89+/-1.92 mg l(-1) over a 28 day culture period. At higher concentrations, i.e. 23.1 and 46.2 microM, however, the lanthanum ion caused significant growth inhibition. For the other three Taxus cell lines, namely an embryo and a leave cell of T. chinensis and a stem cell of T. chinensis marv, the addition of lanthanum ion to the culture only had a significant effect on taxol production by the T. chinensis marv stem cells, increasing the volumetric yield by about threefold to 4.69+/-0.76 mg l(-1). These results suggest that lanthanum has elicitor-like effects on secondary metabolite synthesis of plant cell cultures.

Cell Culture Techniques↗
PubMed2000

Detecting Taxus poisoning in horses using liquid chromatography/mass spectrometry.

A method is described for the analysis of taxine alkaloids by liquid chromatography/mass spectrometry. It is applicable to the detection of taxine alkaloids in the stomach contents of horses in which Taxus poisoning is suspected. Analysis of a leaf extract of Taxus baccata revealed unreported alkaloids of the same relative molecular mass as taxine B and isotaxine B.

Alkaloids↗
PubMed1999

The kinetics of taxoid accumulation in cell suspension cultures of Taxus following elicitation with methyl jasmonate.

Cell suspension cultures of Taxus canadensis and Taxus cuspidata rapidly produced paclitaxel (Taxol) and other taxoids in response to elicitation with methyl jasmonate. By optimizing the concentration of the elicitor, and the timing of elicitation, we have achieved the most rapid accumulation of paclitaxel in a plant cell culture, yet reported. The greatest accumulation of paclitaxel occurred when methyl jasmonate was added to cultures at a final concentration of 200 microM on day 7 of the culture cycle. The concentration of paclitaxel increased in the extracellular (cell-free) medium to 117 mg/day within 5 days following elicitation, equivalent to a rate of 23.4 mg/L per day. Paclitaxel was only one of many taxoids whose concentrations increased significantly in response to elicitation. Despite the rapid accumulation and high concentration of paclitaxel, its concentration never exceeded 20% of the total taxoids produced in the elicited culture. Two other taxoids, 13-acetyl-9-dihydrobaccatin III and baccatin VI, accounted for 39% to 62% of the total taxoids in elicited cultures. The accumulation of baccatin III did not parallel the pattern of accumulation for paclitaxel. Baccatin III continued to accumulate until the end of the culture cycle, at which point most of the cells in the culture were dead, implying a possible role as a degradation product of taxoid biosynthesis, rather than as a precursor.

Acetates↗