Screening for pharmaceutically important taxoids in Taxus baccata var. Aurea Corr. with CC/SPE/HPLC-PDA procedure

Needles of 'the golden yew' Taxus baccata var. Aurea Corr. were extracted w ith methanol followed by pre-purification of the crude extract and column c hromatographic (CC) separation on florisil in gradient mode (an increasing concentration of acetone in dichloromethane). The obtained fractions were c oncentrated 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-d eacetylbaccatin III, baccatin III, paclitaxel and cephalomannine), but also , on the basis of chromatographic behaviour and UV spectrum, 10-deacetylate d 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 C orr. the largest amounts isolated were of 10-deacetylbaccatin III, then 10- deacetylpaclitaxel and 7-xyloside-10-deacetylpaclitaxel, all compounds cons idered to be paclitaxel precursors in semisynthesis. The efficient mechanis m of the separation of 10-acetylated taxoids from their 10-deacetylated der ivatives on florisil on the basis of electron acceptor-electron donor inter actions is discussed. Copyright (C) 2000 John Wiley & Sons, Ltd.