10-Deacetylcephalomannine

[Industrial preparative chromatography purification of 10-deacetylpaclitaxel, the enzymatic product of 7-xylosyl-10-deacetylpaclitaxel].[Pubmed:22679831]

Se Pu. 2012 Feb;30(2):165-9.

A scheme for industrial preparative chromatography purification of 10-deacetylpaclitaxel (10-DAP), the semi-synthesized precursor of anticancer drug paclitaxel was developed. 7-Xylosyl-10-deacetylpaclitaxel (10-DAXP) is the most abundant constitute in the needles of Taxus Chinensis, a specific yew species distributed in China. 10-DAXP has been recognized as a good material to convert into 10-DAP, the most ideal precursor of paclitaxel. The partially purified extract from yew needles which mainly contains 10-DAXP (> 60%) and other two minor 7-xylosyl-10-deacetyltaxanes including 7-xylosyl-10-Deacetylcephalomannine (10-DAXC) and 7-xylosyl-10-deacetylpaclitaxel C (10-DAXP C), was used as the starting material. The total scheme can be divided into four steps. Firstly, the starting material was hydrolyzed by beta-xylosidase to remove the C-7 xylosyl group completely; and then the hydrolyzed products mainly containing 10-DAP were eluted on a column packed with resin to get crude 10-DAP (with the purity of 20.5%) with high yield (96.3%). The crude 10-DAP was purified by a column packed with normal phase, and then by a reversed-phase preparative chromatography with ODS as the solid phase. After these two steps, the purity of the aim product 10-DAP was 96% with the overall yield of 79.7%. This novel scheme was suitable for large-scale purification of 10-DAP from 10-DAXP.

Microbial transformation of cephalomannine by Luteibacter sp.[Pubmed:18001087]

J Nat Prod. 2007 Dec;70(12):1846-9.

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.

Growth inhibitory activity of wood of Taxus yunnanensis and its liquid chromatography Fourier-transform mass spectrometry analysis.[Pubmed:16902867]

Planta Med. 2006 Oct;72(13):1241-4.

The wood of Taxus yunnanensis (Taxaceae) showed growth inhibitory activities against human cancer cell lines, such as cervical HeLa adenocarcinoma. The morphological changes indicated that the cellular growth inhibitions were caused by apoptosis. To determine the active components, T. yunnanensis wood was analyzed by using a liquid chromatography-Fourier-transform MS (LC/FT-MS) technique. As a result, taxane-type diterpenes, such as 10-Deacetylcephalomannine and 10-deacetyltaxol, were found to be present in amounts consistent with the growth inhibitory activity.

Diastereomers of dibromo-7-epi-10-deacetylcephalomannine: crowded and cytotoxic taxanes exhibit halogen bonds.[Pubmed:16539375]

J Med Chem. 2006 Mar 23;49(6):1891-9.

The diastereomers of dibromo-7-epi-10-Deacetylcephalomannine (6 and 7) have been isolated and characterized. Cytotoxicity and microtubule assembly assays demonstrate that cephalomannine analogue 6 possesses a potency profile very similar to that of Taxol, while isomer 7 is slightly less active. Solid state, solution, and tubulin-bound conformations of the two diastereomers were probed by using X-ray crystallography, 2-D NMR experiments in conjunction with the NAMFIS analysis, and the Glide docking protocol. In the crystal, isomer 7 exhibits an intermolecular halogen bond that may contribute to self-assembly. Neither crystal structure appears in the NAMFIS solution analysis, but both diastereomers are represented in solution by a T-shaped Taxol conformer. Glide docking demonstrates the latter to best fill the tubulin binding pocket, as has been shown for the parent Taxol drug. Each model of the bound complexes for 6 and 7 presents a single well-defined halogen bond from one of the ligand's bromines to Glu22 or Asp26 near the N-terminus of beta-tubulin, respectively. This first report of a halogen bond between taxanes and tubulin may prove useful in guiding the design and synthesis of other microtubule-stabilizing agents with a similar capacity.

Crystallographic determination of stereochemistry of biologically active 2'',3''-dibromo-7-epi-10-deacetylcephalomannine.[Pubmed:15664868]

Bioorg Med Chem Lett. 2005 Feb 1;15(3):839-42.

The stereochemistry at C2'' and C3'' of two diastereomers of 2'',3''-dibromo-7-epi-10-Deacetylcephalomannine (6 and 7), which were synthesized by reacting 7-epi-10-Deacetylcephalomannine (5) with bromine, were assigned unambiguously based on crystallographic studies of 6. The X-ray crystallographic analysis shows that 6 adopts an absolute configuration of (2''S,3''R), and 7 can be assigned as (2''R,3''S) configuration. The side-chain conformation of 6 was revealed to be different with the known hydrophobic collapse and the apolar conformations, as found in solid state and in solution. However, most side-chain torsion angles of 6 were found to be very similar to those of tubulin-bound T-shaped conformation (T-Taxol). Both 6 and 7 showed strong in vitro paclitaxel-like activity.

Preparation and evaluation of new brominated paclitaxel analogues.[Pubmed:15621631]

J Asian Nat Prod Res. 2005 Jun;7(3):231-6.

Two diastereomers of 2'',3''-dibromo-7-epi-10-Deacetylcephalomannine, 4 and 5, have been synthesized, purified and identified for evaluation as antitumour drugs. The cytotoxicity of the two diastereomers, assessed in cell culture against MCF-7 breast cancer, A549 lung cancer and A2780 ovarian cancer, was slightly stronger than that of paclitaxel. The cytotoxicity of 5 outweighs that of 4. In the light of the difference in cytotoxicity between the two diastereomers, we can assume that the differing configurations of C-2'' and C-3'' of the two diastereomers may result in different bioactive conformations in solution and, consequently, different biologically relevant conformations for binding to tubulin/microtubules -- a matter we are studying further.

Distribution of paclitaxel and its congeners in Taxus mairei.[Pubmed:11677011]

Fitoterapia. 2001 Nov;72(7):743-6.

Concentrations of paclitaxel and its congeners 10-deacetylpaclitaxel, cephalomannine, 10-Deacetylcephalomannine, baccatin III and 10-deacetylbaccatin III in Taxus mairei were determined by HPLC. It was found that paclitaxel is abundant in roots and stem bark. The concentrations of paclitaxel and its congeners in the plants growing in one area may vary to a great extent from those growing in another area.

Screening for pharmaceutically important taxoids in Taxus baccata var. Aurea corr. with CC/SPE/HPLC-PDA procedure.[Pubmed:11113935]

Biomed Chromatogr. 2000 Dec;14(8):516-29.

Needles of 'the golden yew' Taxus baccata var. Aurea Corr. were extracted with methanol followed by pre-purification of the crude extract and column chromatographic (CC) separation on florisil in gradient mode (an increasing concentration of acetone in dichloromethane). The obtained fractions were concentrated and purified on silanized silica gel SPE cartridges and taxoids eluted with 75% methanol were analysed by HPLC-PDA procedure using Waters Symmetry C(18) column with gradient elution. The applied method enabled not only determination of four taxoids commonly occurring in yew extracts (10-deacetylbaccatin III, baccatin III, paclitaxel and cephalomannine), but also, on the basis of chromatographic behaviour and UV spectrum, 10-deacetylated taxoids (10-deacetylpaclitaxel, 10-Deacetylcephalomannine, 7-xyloside-10-deacetylpaclitaxel and 10-deacetyltaxol C) could be detected together with 7-epi-10-deacetylpaclitaxel. From the needles of Taxus baccata var. Aurea Corr. the largest amounts isolated were of 10-deacetylbaccatin III, then 10-deacetylpaclitaxel and 7-xyloside-10-deacetylpaclitaxel, all compounds considered to be paclitaxel precursors in semisynthesis. The efficient mechanism of the separation of 10-acetylated taxoids from their 10-deacetylated derivatives on florisil on the basis of electron acceptor-electron donor interactions is discussed.

Taxol production in nodule cultures of Taxus.[Pubmed:8882426]

J Nat Prod. 1996 Mar;59(3):246-50.

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.

Taxol and its related taxoids from the needles of Taxus sumatrana.[Pubmed:7728941]

Chem Pharm Bull (Tokyo). 1995 Feb;43(2):365-7.

Through bioassay-guided separation of the chemical constituents of the needles of Taxus sumatrana, taxol (1), cephalomannine (2), and a new taxoid 19-hydroxy-13-oxobaccatin III (8) have been isolated together with 7-epi-10-deacetyltaxol (3), 7-epi-10-Deacetylcephalomannine (4), baccatin III (5), 19-hydroxybaccatin III (6), and 10-deacetyl-13-oxobaccatin III (7). The chemical structure of 8 has been elucidated on the bases of its chemical and physicochemical properties.

Analysis of taxol and related diterpenoids from cell cultures by liquid chromatography-electrospray mass spectrometry.[Pubmed:8101526]

J Chromatogr. 1993 Jun 2;615(2):273-80.

Authentic taxanes (taxol, 10-deacetyltaxol, cephalomannine, 10-Deacetylcephalomannine, baccatin III) and extracts from cell cultures derived from various yew tree species have been analyzed by microbore high-performance liquid chromatography (HPLC)-electrospray mass spectrometry (ESMS). All gave excellent positive-ion ES spectra with dominant protonated molecules at low nozzle-to-skimmer bias value (45 V). By increasing the voltage value to 85 V, fragmentation increased and structurally informative spectra were obtained. The fragments found were both of the C-13 side-chain and of the taxane ring, so their analysis gave important information about the taxane structure and any chemical modifications at different positions of the molecule. When tandem MS was used (argon gas, 25 eV collision energy), fragments similar to those obtained from collision-induced dissociation in the source were detected. The cell culture extracts were analyzed by microbore HPLC-ESMS and excellent spectra were obtained on 5-10 ng of separated compounds; even greater selectivity and sensitivity were obtained through use of selected-ion monitoring (SIM). With SIM, 100 pg of all taxanes could readily be detected. In the HPLC-ESMS mode, only 10% of the eluent was mass-analyzed, so 90% would be available for recovery through fraction collecting.

Taxol and related taxanes. I. Taxanes of Taxus brevifolia bark.[Pubmed:8097872]

Pharm Res. 1993 Apr;10(4):521-4.

The published procedures for the isolation of taxol from the Pacific yew (Taxus brevifolia) and other species of Taxus are cumbersome, and the yields of taxol are in the range of 0.0075-0.01%. This paper describes a simple and efficient procedure for the isolation of taxol and its major natural analogues from the bark of T. brevifolia consisting of a single chromatographic column (using silica gel, Florisil, or a reverse-phase C18-silica), followed by crystallization. Isolated yields of taxol from five "pooled" bark samples (blended from many different batches by the supplier) were in the range of 0.02-0.04%, and from bark collected from a more restricted locale, yields reached 0.06%. The procedure also yielded taxol analogues, such as 10-deacetylbaccatin III (0.02-0.04%), 10-deacetyltaxol-7-xyloside (0.06-0.1%), taxol-7-xyloside (0.005-0.01%), 10-deacetyltaxol (0.01-0.02%), 10-Deacetylcephalomannine-7-xyloside (0.006-0.01%), and cephalomannine (0.005-0.007%). Of these, 10-deacetyltaxol-7-xyloside is the most abundant taxane in the Pacific yew bark.

19-Hydroxybaccatin III, 10-deacetylcephalomannine, and 10-deacetyltaxol: new antitumor taxanes from Taxus wallichiana.[Pubmed:7264680]

J Nat Prod. 1981 May-Jun;44(3):312-9.

Activity-guided, chromatographic fractionation for a polar extract of Taxus wallichiana Zucc. (originally identified as Cephalotaxus mannii Hook.) resulted in the isolation of three new KB cytotoxic taxane derivatives. Nmr and ms spectral analyses permitted their characterization as 19-hydroxybaccatin III (3), 10-Deacetylcephalomannine (4), and 10-deacetyltaxol (5). The latter two compounds, which are also active against PS leukemia in vivo, were observed to be especially labile, each forming equilibrium mixtures with their cytotoxic C-7 epimers (9, 10).