[LC-ESI-MS metabolic profiling analysis of taxanes from the extracts of Taxus chinensis cell cultures].

AIM

To develop a rapid analytical method for small amount biological samples of taxanes by using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS) in small amount biological samples.

METHODS

A solution containing five given taxane constituents and the extract from cell cultures of Taxus chinensis were analysed separately. According to the performance of the given taxanes in ESI-MS/MS, run parameters of the mass spectrometer were optimized. Positive and negative electrospray modes were employed to simultaneously scan the cell cultures sample, and the full ion chromatogram and the molecular weight of individual peak were obtained. The qualitative analysis of taxanes was achieved by comparison of the retention time and molecular weight with those of the reference substances or was based on the interpretation of the MS/MS spectra of the analytes and the knowledge of the concerning genetic backgrounds of taxanes published in literatures.

RESULTS

The taxanes with several acetyl substituents tended to produce ammonium adduct ions peak, while multi-hydroxy taxanes were subject to give protonized molecular ion peaks in positive ion ESI-MS. Thirteen taxanes in cell samples were assigned. Eight compounds of them were identified to be 1 -acetyl-5, 7, 10-deacetyl-baccatin I (DAB-I, 1) , baccatin III (B-III, 3), baccatin VI (B-VI, 8), taxol (9), yunnanxane (10 ), taxuyunnanine C (Tc, 11), sinenxane B (12), sinenxane C (13), separately. For the other five constituents, character of taxane and the number of substituents were deduced.

CONCLUSION

The results confirm the feasibility of characterizing taxanes in biological samples by LC-ESI-MS analysis. The analytical methodology provided a rapid, conventional and reliable tool to study metabolic profiling of taxanes for structural elucidation in taxol biosynthesis.