Cell culture of Taxus as a source of the antineoplastic drug taxol and related taxanes.

Callus cultures of Taxus cuspidata and Taxus canadensis were induced using different tissue explants including green and red arils, seed contents, young stems and needles. Callus derived from stem segments displayed the best growth in defined media. The culture medium was supplemented with reducing agents and phenolic-binding compounds to inhibit callus darkening and subsequent growth reduction. T. cuspidata explant growth was affected by different concentrations and ratios of 2,4-D and kinetin. Callus tissues of T. cuspidata were extracted for taxol after 2 months in culture and analysed by HPLC. The presence of taxol (0.020 +/- 0.005% of the extracted dry weight) was indicated based on retention time, U.V. spectra, peak purity as assessed by photo-diode array spectroscopy and compared with an authentic taxol standard, as well as by 1H-NMR analysis. Suspension cultures of T. cuspidata were established from the callus cultures, subsequently immobilized onto glass fiber mats, and maintained as immobilized cultures for 6 months. The immobilized cell cultures also produced taxol at levels up to 0.012 +/- 0.007% of the extracted dry weight.