European yew tree

Environmental groups objected to this practice, and many demonstrations were staged. A solution was eventually found when the needles of the European yew tree Taxus baccata) provided a source for the paclitaxel precursor without destroying the bark. 

Docetaxel is a semisynthetic taxane derived from the European yew tree. Its mechanism of action, metabolism, and elimination are identical to those of paclitaxel. It is approved for use as second-line therapy in advanced breast cancer and non-small cell lung cancer, and it also has major activity in head and neck cancer, small cell lung cancer, gastric cancer, advanced platinum-refractory ovarian cancer, and bladder cancer. Its major toxicities are listed in Table 54-4. 

Figure 7.4 European yew tree Taxus baccata) close-up of leaves.

With the successful development and commercial manufacture of semi-synthetic Taxol , tile destruction of the Pacific yew tree forests was halted. However, this successful move away from an essentially non-renewable source (extraction of the Pacific yew tree bark) to a renewable source (harvested European yew tree leaves and twigs to obtain 10-DAB, followed by syntliettc transformation to Taxol ) still presented significant environmental challenges. The use of 13 different solvents. 

Paclitaxel (Taxol ) is an anti-cancer agent originally obtained from Pacific yew tree bark. The complexity of the molecule makes chemical synthesis from simple compounds economically unfeasible. For instance, one of the most efficient semisyntheses starts from 10-deacetylbaccatin III, a more abundant taxoid obtained from needles of the European yew tree (Scheme 8.16) [67,68], However, the process is still long, requiring 11 chemical transformations. 

Due to scarcity of paclitaxel, extensive research was carried out leading to the formulation of docetaxel (Fig. 101.4), an esterified product of 10-deacetyl baccatin 111, which is extracted from the renewable and readily available leaves of European yew tree. 

European yew tree needles - http //commons.wikimedia.org/ wiki/File Taxus baccata 0 l ies.jpg... 

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