Identification of Six Taxine Alkaloids from Taxus baccata Needles

Abstract

Six taxine alkaloids were isolated from Taxus baccata needles and partially separated. An HPLC method for the analysis of the taxine fraction was developed. By NMR and deamination/hydrolysis studies it was established that the taxine fraction consisted mostly of taxicin-I and taxicin-II derivatives in a variable ratio. Four of the six taxine alkaloids isolated have not been reported before. All of the alkaloids were found to be unstable under neutral and basic conditions, and some of them were very easily interconverted.

Quantitative determination of taxine B in body fluids by LC–MS–MS

“…The identity of the substance was confirmed by NMR data [15,26], exact mass measurement and LC-MS-MS.…”

“…This step was followed by a liquid-liquid extraction and column separation over neutral alumina according to Jenniskens et al [15].…”

“…The main pseudo-alkaloid of the taxine fraction is taxine B, and it is assumed to be responsible for the toxicity of the plant [5,15,16]. The toxic action of taxine B is based on cardiac effects.…”

Semisynthesis of Flexible 5,7-Dideoxypaclitaxel Derivatives from Taxine B

“…40%) of an alkaloid mixture from T. baccata, easily obtained in 0.5Ϫ1% yield by acid extraction of dried leaves. [8] Although the structures of taxines 6aϪ6f are quite distinct from paclitaxel, several groups have used these alkaloids to prepare 7-deoxypaclitaxel derivatives in a reasonable number of steps. [9Ϫ14] The crude alkaloid mixture was purified and converted into a mixture of compounds 7a and 7b by iodomethylation, saponification of the acetate groups with concomitant elimination of the trimethylammonium group, protection of the 9-and 10-hydroxy groups with an isopropylidene bridge, and protection of the 1-and 2-hydroxy groups with a benzylidene bridge as previously described (Scheme 1).…”

Semisynthesis of 7‐Deoxypaclitaxel Derivatives Devoid of an Oxetane D‐Ring, Starting from Taxine B

“…40%) of this alkaloid mixture. [15] Although the structures of taxines 11aϪ11f are quite distinct from that of paclitaxel, several groups have used them to prepare 7-deoxypaclitaxel and derivatives. [9,16Ϫ21] These derivatives all lack a hydroxy group at C-7 and sometimes have a substitution pattern at C-9 and C-10 that differs from that of paclitaxel.…”