Targeted LC-MS/MS analysis for the quantification of taxanes: assessment of chemodiversity in different European yew (Taxus baccata) populations from Greece

Taxus baccata is a native to Greece medically interesting conifer due to its tetracyclic diterpenes. Amongst them, the anti-cancer agent paclitaxel is the most known. This study evaluated the content of five diterpenes found in the needles of 130 T. baccata trees belonging to three populations from different mountainous areas and one ex-situ collection, as an alternative source of taxanes. In order to assess the chemodiversity of the populations, fresh needles were collected in August from second and third year stems/branches with northern exposure from each tree and freeze-dried. The phytochemical extraction in triplicate was performed according to Mubeen et al. (2018) with modifications, by mixing 500 mg of dried needles with 4 ml acetone:water (3:2 v/v). After evaporation of acetone the pooled water phase was extracted twice with 4 mL dichloromethane. and the two phases were evaporated until complete dry. The residues were dissolved in 1 ml methanol and filtered into glass vials. An analytical method was developed using external standards for quantification, according to Kobusiak-Prokopowicz et al. (2016) and validated to quantify paclitaxel, 10-deacetylbaccatin III (DAB), 10-diacetyltaxol (DAT), baccatin III and cephalomanine, using UPLC-MS/MS (MRM). Analysis revealed that mean concentration of DAB, DAT, cephalomanine and paclitaxel ranged from 162.3-703.4, 14.7-17.5, 19.2-29.3 and 17.8-29.7 mg Kg^-1 dw respectively in the needles of the examined populations [Fig. 1], while baccatin III was identified only in traces. Such chemodiversity could lead to the selection of superior germplasm native to Greece for further exploitation destined to the production of important taxanes.

Fig. 1 The variation of major taxanes (DAB, DAT, Cephalomanine and Paclitaxel) identified in the needles of trees from four different Greek populations of Taxus baccata. Values are expressed as means ± standard error. Biological replicates were n = 23-33 trees per population.

• References

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