Taxane Diterpenoids from Seeds of Texus mairei.

“…Verticillene is considered to be the most likely intermediate between geranylgeranyl pyrophosphate and the taxane diterpenes. [3][4][5] In continuation of our research on the taxane diterpenoids of endemic Taxus species, [6][7][8][9][10][11][12][13][14] a phytochemical study of T. sumatrana was carried out. A chromatographic fractionation of an acetone extract of the leaves and twigs of the plant has resulted in the isolation of three new taxane diterpenes, named tasumatrols M (1), N (2) and O (3).…”

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confidence: 99%

New Bicyclic Taxane Diterpenoids from Taxus sumatrana

Shen

Hsu

Lin

et al. 2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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The chemical constituents of Taxus have been extensively investigated worldwide as a result of the discovery of paclitaxel with its remarkable anti-cancer activity.1,2) Although more than 450 taxane diterpenes have been discovered to date, the biogenesis of paclitaxel and taxoids is still unclear. Verticillene is considered to be the most likely intermediate between geranylgeranyl pyrophosphate and the taxane diterpenes. [3][4][5] In continuation of our research on the taxane diterpenoids of endemic Taxus species, [6][7][8][9][10][11][12][13][14] a phytochemical study of T. sumatrana was carried out. A chromatographic fractionation of an acetone extract of the leaves and twigs of the plant has resulted in the isolation of three new taxane diterpenes, named tasumatrols M (1), N (2) and O (3). In addition, two known taxane, 7-deacetylcanadensene (4) and 2a,7b,13a-triacetoxy-5a,9a-dihydroxy-2(3→20) abeotaxa-4(20),11-dien-10-one were also isolated. The structures of 1-3 were established on the basis of spectroscopic analyses, especially 1-and 2D NMR.The HR-ESI-MS of 1 revealed a quasi-molecular ion peak at m/z 575.2466 [MϩNa] ϩ consistent with the molecular formula C 28 H 40 O 11 and nine degrees of unsaturation. The IR spectrum displayed absorption bands diagnostic of hydroxyl, double bonds and ester groups. Both showed HMBC correlation with C-7, C-8 and C-9 at d C 62.6, 128.2 and 141.1. The relative configuration of 1 was determined through comparing 1 H-NMR data and the coupling constants with those of 7-deacetylcanadensene (4) 17) and from its NOESY spectrum that showed correlations between H-10/H-7; H-1/Me-16; Me-17/H-2 and H-13/Me-16 (Fig. 1). Finally, acetylation of 1 provided compound 5 identical with a product derived from acetylation of 4. Hence, the structure of 1 was established and named tasumatrol M.The HR-ESI-MS of 2 revealed the molecular formula C 28 H 38 O 11 (two protons less than 1), as derived from a quasimolecular ion at m/z 573.2310 ([MϩNa] ϩ ). The 13 C-NMR of 2 (Table 2) Investigation of an acetone extract of the leaves and twigs of Taxus sumatrana has resulted in the isolation of two new bicyclic taxoids, tasumatrols M (1), and N (2) and a new baccatin III derivative, tasumatrol O (3) together with the previous known 7-deacetylcanadensene (4) and 2a a,7b b,13a a-triacetoxy-5a a,9a a-dihydroxy-2(3→20) abeotaxa-4(20),11-dien-10-one. The structures of these taxanes were established on the basis of spectroscopic analyses, especially 1-and 2D NMR, and chemical derivatization.

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“…[1][2][3] Taiwan yew Taxus mairei is an evergreen shrub growing at high altitudes (2600 m) in the northern and central parts of Taiwan. Recent studies on the taxane diterpenoids of T. mairei have resulted in the isolation of taxumairols N and O from the roots, 4) and taxumairol R from the root bark, 5) taxumains A and B from the twigs, 6) taxumairol M and taxumairone A from the seeds, 7,8) 13-deacetylcanadensene and 7-deacetylcanadensene from the needles, 9) and taxumairols U-W from the stem bark. 10) Owing to the special geographic and weather conditions, yew trees grown in Taiwan appear different from Taxus chinensis var.…”

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confidence: 99%