1. Taxanes: From Yew Tree Bark and Needles and Soil!
Alex Samuels1 and Angela Hoffman, Department of Chemistry, University of Portland, Portland OR now at Washington State University, Chemistry Department, Pullman, WA
Introduction
Methods
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Taxanes are molecules with a large ring structure similar to Taxol (paclitaxel).
Taxol is a cytotoxic diterpene that was originally found in the bark of the Pacific yew tree, Taxus brevifolia in Today, it is an important chemotherapy agent used to treat lung, ovarian, breast and other cancers. It is also used to coat stents implanted into blood vessels, etc.
The most common technique for obtaining the drug is to extract it from Taxus plant material or to extract taxanes such as baccatin III from the plant and produce Taxol by semisynthesis. We have shown that taxanes, including paclitaxel, can be extracted from liquid plant culture medium in which yew tree cuttings have been incubated (Hoffman 1996). Our goal here was to increase the yield of paclitaxel per tree by extracting taxanes from soil, sand, Perlite, and water runoff from trees grown in field and greenhouse.
Extraction of taxanes from soil:
• Measure volume and mix soil with methanol or isopropyl alcohol and shake for a minimum of 1 hour.
• Filter through Miracloth or pour into a large chromatography column; collect and evaporate solvent.
• Remove salts over a C-18 column, and concentrate.
• Separate and quantify by LC; verify taxanes by LCMS.
Extraction of taxanes from sand and Perlite:
• Dry the solids and measure volume. Proceed as for soil.
Extraction of taxanes from runoff water:
• Collect water and store in refrigerator or freezer until it is extracted.
• Pump water through C-18 column or XAD-2.
• Rinse with water several times, remove taxanes with methanol, evaporate. 
Taxol
Figure 1 Top: Mass spectrum for Paclitaxel standard
Bottom: Mass spectrum for greenhouse soil
Conclusions
Simple extraction techniques can be used to remove taxanes, including Taxol, from soil, sand, Perlite and water runoff from a greenhouse.
In addition to the extraction from the yew trees, the additional sources of taxanes can increase the yield of these compounds per tree by at least 10%.
3. In the hydroponics experiment, baccatin III, Taxol and other taxanes were detected despite the small sample size.
4. The greatest amount of Taxol is found in the plant (bark, needles and roots, % of mass, dry weight), followed by growth media (soil, g/ft3; Perlite and sand, g/ft3, Table 1). The lowest level of taxanes is found in the runoff water from Perlite or sand ( ng /20 liters over 4 months).
Results
Acknowledgements
Support was provided by NSF grant no University of Portland, Saturday Academy, Lab 2 Market, Weyerhaeuser (Jeff Mehlschau). Special thanks to David Vo, Steven Cheung, Eric Davis, Jim Carlsen, Daniel Cruse