Roots of hydroponically grown Taxus plants as a source of taxol and related taxanes

Taxus x media Rehd. cultivars Brownii (TMB), Densiformis (TMD), Fieldii (TMF), Hicksii (TMH) and T. cuspidata Sieb. and Zucc. varities 'improved' (TC-Imp) and 'special' (TC-Sp) were grown hydroponically in Johnson's nutrient solution (JS) for 22 weeks, at which time they were harvested for analysis. One-tenth strength JS produced the highest biomass for all plants. Plants grown in either one-tenth or one-twentieth strength JS had significantly greater root growth, compared with shoot growth. The highest root to shoot ratio (1.9) was achieved by TC-Sp, followed by TC-Imp (1.8) and TMB (1.8). The concentrations of taxol and 10-deacetyltaxol in the roots of all plants were comparable with or greater than the amounts found in the 'above-ground' parts. TMB (212 ± 43 mg/kg), TMH (381 ± 25 mg/kg), and TC-Sp (317 ± 32 mg/kg) roots contained greater than 1.5-fold amounts of taxol, compared with their needles. However, there were no major differences between the needles and the roots with respect to both cephalomannine and 10-deacetyltaxol levels. The highest taxol concentration was observed in the root bark of TMH (619 ± 50 mg/kg taxol). Cumulative amounts of taxol, cephalomannine and 10-deacetyltaxol found in the root bark of TMH and TC-Imp totaled 1158 and 1159 mg/kg dry matter, respectively. The presence of taxol, cephalomanine and 10-deacetyltaxol was detected and quantified by high performance liquid chromatography, and the structure confirmed by fast atom bombardment mass spectrometry.