Taxane diterpenoids from the stem bark of Taxus mairei

Advancements in the Cultivation, Active Components, and Pharmacological Activities of Taxus mairei

Taxus mairei (Lemée and H.Lév.) S.Y.Hu, indigenous to the southern regions of China, is an evergreen tree belonging to the genus Taxus of the Taxaceae family. Owing to its content of various bioactive compounds, it exhibits multiple pharmacological activities and has been widely applied in clinical medicine. This article comprehensively discusses the current state of cultivation, chemical constituents, applications in the pharmaceutical field, and the challenges faced by T. mairei. The paper begins by detailing the ecological distribution of T. mairei, aiming to provide an in-depth understanding of its origin and cultivation overview. In terms of chemical composition, the article thoroughly summarizes the extracts and monomeric components of T. mairei, unveiling their pharmacological activities and elucidating the mechanisms of action based on the latest scientific research, as well as their potential as lead compounds in new drug development. The article also addresses the challenges in the T. mairei research, such as the difficulties in extracting and synthesizing active components and the need for sustainable utilization strategies. In summary, T. mairei is a rare species important for biodiversity conservation and demonstrates significant research and application potential in drug development and disease treatment.

Taxanes and taxoids of the genus Taxus - A comprehensive inventory of chemical diversity

The pseudoalkaloid diterpene Taxol® (paclitaxel) emerged as a best-selling anti-cancer drug in the mid-1990s. The compound attracted considerable interest because of its unique mechanism to stabilize microtubules, thus reducing dynamicity and ultimately promoting mitotic arrest. Taxol was originally isolated from members of the genus Taxus. Over the last 50 years, close to 600 metabolites with taxane scaffolds were isolated from various Taxus species and their structures reported. The present review article provides an overview of the known chemical diversity of taxanes, with an emphasis on the functionalization of diterpene scaffolds. The implications of the occurrence of chemically diverse taxane metabolites for unraveling Taxol biosynthesis and enabling pathway engineering are discussed as well.

Cytotoxic Activity and Metabolic Profiling of Fifteen Euphorbia Species

Euphorbia is a large genus of flowering plants with a great diversity in metabolic pattern. Testing the cytotoxic potential of fifteen Euphorbia species revealed highest activity of E. officinarum L. against human colon adenocarcinoma (CACO2) cell line (IC₅₀ 7.2 µM) and of E. lactea Haw. against human hepatoma (HepG2) and human breast adenocarcinoma (MCF-7) cell lines (IC₅₀ 5.2 and 5.1 µM, respectively). Additionally, metabolic profiling of the fifteen tested species, using LC-HRMS, for dereplication purposes, led to the annotation of 44 natural compounds. Among the annotated compounds, diterpenoids represent the major class. Dereplication approach and multivariate data analysis are adopted in order to annotate the compounds responsible for the detected cytotoxic activity. Results of Principle component analysis (PCA) come in a great accordance with results of biological testing, which emphasized the cytotoxic properties of E. lactea Haw. A similarity correlation network showed that the two compounds with the molecular formula C₁₆H₁₈O₈ and C₂₀H₃₀O₁₀, are responsible for cytotoxic activity against MCF-7 and HepG2 cell lines. Similarly, the compound with molecular formula C₁₈H₃₅NO correlates with cytotoxic activity against CACO2.

Tissue-specific study across the stem of Taxus media identifies a phloem-specific TmMYB3 involved in the transcriptional regulation of paclitaxel biosynthesis

Taxus stem barks can be used for extraction of paclitaxel. However, the composition of taxoids across the whole stem and the stem tissue-specificity of paclitaxel biosynthesis-related enzymes remain largely unknown. We used cultivated Taxus media trees for analyses of the chemical composition and protein of major stem tissues by an integrated metabolomic and proteomic approach, and the role of TmMYB3 in paclitaxel biosynthesis was investigated. The metabolomic landscape analysis showed differences in stem tissue-specific accumulation of metabolites. Phytochemical analysis revealed that there is high accumulation of paclitaxel in the phloem. Ten key enzymes involved in paclitaxel biosynthesis were identified, most of which are predominantly produced in the phloem. The full-length sequence of TmMYB3 and partial promoter sequences of five paclitaxel biosynthesis-related genes were isolated. Several MYB recognition elements were found in the promoters of TBT, DBTNBT and TS. Further in vitro and in vivo investigations indicated that TmMYB3 is involved in paclitaxel biosynthesis by activating the expression of TBT and TS. Differences in the taxoid composition of different stem tissues suggest that the whole stem of T. media has potential for biotechnological applications. Phloem-specific TmMYB3 plays a role in the transcriptional regulation of paclitaxel biosynthesis, and may explain the phloem-specific accumulation of paclitaxel.

New Bicyclic Taxane Diterpenoids from Taxus sumatrana

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 2alpha,7beta,13alpha-triacetoxy-5alpha,9alpha-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.

Two New Cytotoxic Clerodane Diterpenoids from Casearia membranacea

In addition to casearlucin A (3), two new clerodane diterpenes, caseamembrols A (1) and B (2) have been isolated from the leaves and twigs of Casearia membranacea by bioassay-guided fractionation. The structures of the new compounds were established on the basis of extensive 1D- and 2D-NMR spectroscopic analysis. Compounds 1-3 exhibited significant cytotoxicity against human prostate (PC-3) cancer cells.

Microbial transformation of baccatin VI and 1β-Hydroxy baccatin I by aspergillus niger

The biotransformation of baccatin VI (1) and 1beta-hydroxybaccatin I (2) with the filamentous fungus Aspergillus niger produced four new taxane diterpenoids taxumairol S(1) (3), taxumairol T(1) (4) and taxumairol S (5), taxumairol T (6), respectively. 1beta-Dehydroxybaccatin VI (7) remained unreacted under the same condition.

New taxane diterpenoids from Taiwanese Taxus sumatrana

Two new taxane diterpenoids, tasumatrols A (1) and B (2), have been isolated from extracts of the leaves and twigs of Taiwanese Taxus sumatrana. Tasumatrol A is a rare 5/6/6 taxene system, having a novel gamma-lactone at C-10 and C-19. The structures of compounds 1 and 2 were determined on the basis of two dimensional (2D)-NMR techniques, including correlation spectroscopy (COSY), 1H-detected heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond connectivity (HMBC) experiments.

Taxumairols X--Z, new taxoids from Taiwanese Taxus mairei

In addition to 19-dydroxybaccatin III, 1beta-hydroxy-5 alpha-deacetylbaccatin I, taxayuntin G and 13-O-deacetyltaxumairol Z (4), three new taxane diterpenoids, taxumairols X (1), Y (2), Z (3) have been isolated from extracts of the Formosan Taxus mairei (LEMEE & LEVL.) S. Y. HU. Compounds 1-2 belong to the 11(15-->1)-abeo-taxane system, having a tetrahydrofuran ring at C-2, C-3, C-4 and C-20. The new compound 3 and 4, which was misidentified previously are derivatives of 11(15-->1)-abeo-taxane with an intact oxirane system. The structures of compounds 1-4 were elucidated on the basis of extensive two dimensional (2D)-NMR analysis.

Multidrug resistant cancer cells susceptibility to cytotoxic taxane diterpenes from Taxus yunnanensis and Taxus chinensis

Twelve taxane diterpenes (1-12), which were isolated previously from the EtOH extract of the aerial parts of Taxus yunnanensis or Taxus chinensis, were evaluated for cytotoxicity against the multidrug resistant cancer cells KB-VIN and KB-7d. Compounds and showed significant cytotoxicity in these cell lines. Compounds and also demonstrated significant activity against KB-7d. The biflavonoid isolated from T. yunnanensis was only marginally cytotoxic against the A549 (lung) cell line, but a simple methoxylated analogue (14) was inactive.

New taxane diterpenoids from the roots of Taiwanese Taxus mairei

Five new taxane diterpenoids, taxumairols G (1), H (2), I (3), J (4), and L (5) were isolated from extracts of the roots of Taiwanese Taxus mairei (LEMEE & LEVL.) S. Y. Hu. Compounds 1-4 belong to the new 11(15-->1)-abeo-taxene system, having a tetrahydrofuran ring along carbons C-2, C-3, C-4 and C-20. Compounds 3 and 4 contain an isopropenyl group at C-1 while compounds 1 and 2 are attached with a benzoxyl group at C-15. The structures of compounds 1-5 were determined on the basis of two-dimensional (2D)-NMR techniques including correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond correlation (HMBC), and nuclear Overhauser effect spectroscopy (NOESY) experiments.