Taxin B

Eight cases of fatal and non-fatal poisoning with Taxus baccata.[Pubmed:23265441]

Forensic Sci Int. 2013 Apr 10;227(1-3):118-26.

This paper describes two fatalities, three non-fatal intentional and three accidental oral ingestions of yew (Taxus baccata) leaves. In all cases the post-mortem external examinations showed no signs of violence. Internal examinations revealed small green, needle-like particles on the tongue, in the esophagus and in the stomach. Yew leaves were also identified in the stomach contents, whereas Taxus leaves were cut into small pieces and then ingested in one case. The analytical method used was based on a liquid-liquid-extraction under alkaline conditions followed by LC-MS/MS analysis (QTRAP 5500). Chromatographic separation was achieved by HPLC on a Kinetex C18 2.6u (100x3) mm. The analytical method allows the simultaneous identification and quantification of the commercially available yew alkaloids taxoids (m/z): paclitaxel (854.2-->105.0/286.1), 10-deacetyltaxol (10-DAT: 812.2-->105.0/286.1), baccatin III (BAC III: 604.0-->105.0/327.0), 10-deacetylbaccatin III (10-DAB III: 562.1-->105.0/327.0), cephalomannine [taxol B] (562.1-->105.0/327.0) and of 3,5-dimethoxyphenol (3,5-DMP: 155.0-->111.9/122.9) also encompassing the qualitative analysis of the alkaloidal diterpenoids (Q1-->194.0/107.0); reference mass spectra obtained from a yew leaves extract: monoacetyltaxine (MAT: 568.4), taxine B (584.2), monohydroxydiacetyltaxine (MHDAT: 626.4), triacetyltaxine (TAT: 652.4), monohydroxytriacetyltaxine (MHTAT: 668.4). In both fatalities, paclitaxel, 10-DAT and cephalomannine were not identified in urine, cardiac and femoral blood but all taxoids and 3,5-DMP were present in stomach content and excreted into the bile. In urine, highest 3,5-DMP concentration was 7500 mug/L and 23,000 mug/L after enzymatic hydrolysis, respectively. In intentional and accidental poisonings, when electrocardiogram (ECG) examinations revealed ventricular tachycardia and/or prolonged QRS intervals, taxines were identified in plasma/serum, even after the ingestion of a few number of yew leaves, when 3,5-dimethoxyphenol was not even found. According to the data from one near-fatal intentional poisoning, elimination half-life of MAT, Taxin B, MHDAT and MHTAT in serum was calculated with 11-13 h and taxines were detected up to t=+122 h post-ingestion of approximately two handfuls of yew leaves.

Taxane-derived compounds protect SK-N-SH cells against oxidative stress injury induced by H2O2.[Pubmed:28330425]

Neurol Res. 2017 Jul;39(7):632-639.

OBJECTIVE: Discussed the protection of taxane-derived compounds, 7-deacetyl-taxine B and 5-cinnamoyloxy-Taxin B, against oxidative stress injury. METHODS: SK-N-SH cells were pretreated with 7-deacetyl-taxine B, 5-cinnamoyloxy-Taxin B or DMSO (control) and then incubated with H2O2 for another 24 h. Cell viability was measured by MTT colorimetric assay. Apoptosis rate, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were detected using flow cytometry assay. Ultrastructure was detected by Transmission electron microscope. RESULTS: Taxane-derived compounds improved H2O2 mediated loss of cell viability in SK-N-SH cell. Ultrastructure of control group cells showed nucleus shrinkage, dense aggregation of chromatin, appearance of apoptotic body and mitochondrial dilation. Treated group showed alleviation of mitochondrial dilation and chromatin margination, and reduction of apoptosis cells induced by H2O2. The apoptosis rate was decreased in treated group compared with control group. DCFH-DA staining showed that ROS were significantly decreased in cells treated with taxane-derived compounds compared with control group. Rhodamine123 staining showed that MMP was significantly decreased in cells treated with taxane-derived compounds compared with control group. CONCLUSION: The anti-oxidative stress and neuroprotective effect of taxane-derived compounds was verified here, wherein it could protect neurocytes from H2O2-induced oxidative stress injury.

New taxoids from the seeds of taxus chinensis[Pubmed:9917305]

J Nat Prod. 1999 Jan;62(1):149-51.

Two new taxoids, 2alpha-acetoxy-2',7-dideacetoxyaustrospicatine (1) and decinnamoyltaxinine E (2), have been isolated from the extracts of the seeds of the Chinese yew Taxus chinensis (Pilg.) Rehd. in addition to taxuspine Z (3), Taxin B (4), taxezopidine G (5), 7, 2'-bisdeacetoxyaustropicatine (6), 5alpha-cinnamoyl-9alpha,10beta, 13alpha-triacetoxytaxa-4(20),11-diene (7), taxachitriene A, 20-deacetyltaxachitriene A, 13-O-acetylbrevifoliol, taxinines A and J, and taxacin. The structures of these compounds were elucidated on the basis of spectral analysis and chemical derivatizations.

Taxane diterpenoids from seeds of Taxus mairei.[Pubmed:10993234]

Chem Pharm Bull (Tokyo). 2000 Sep;48(9):1344-6.

A new 2(3-->20) abeotaxane, taxumairone A (1), and a new cis-p-coumaroyl myo-inositol have been isolated from the seeds of Taxus mairei in addition to Taxin B (2), taxinine A, taxuspine X, decinnamoyltaxinine E, 5alpha-cinnamoyloxy-9alpha,10beta,13alpha- triacetoxy-taxa-4(20)11-diene and 5alpha-cinnamoyloxy-2alpha,9alpha,10beta,+ ++13alpha-tetraacetoxy-taxa-4(20)11-diene. The structure of 1 was determined by 2D-NMR spectral analysis and chemical correlation with Taxin B (2). Compound 1 exhibited potent cytotoxicity against human colon carcinoma cells with an ED50 of 0.1 microg/ml.

Rearranged taxoids from Taxus yunnanensis.[Pubmed:7480192]

Planta Med. 1995 Aug;61(4):375-7.

Two rearranged 2(3-->20)abeotaxanes were isolated from the leaves and stems of Taxus yunnanensis, and designated as Taxin B and 2-deacetylTaxin B. The structure of Taxin B with a unique 6/10/6 skeleton was deduced on the basis of 1H-NMR, 13C-NMR, 1H-1H COSY, DEPT, NOE, and mass spectra and confirmed by X-ray crystallographic analysis. The structure of 2-deacetylTaxin B is elucidated by analog.