|Ketchum, Raymond - CORNELL UNIVERSITY|
|Tandon, Manish - CORNELL UNIVERSITY|
|Begley, Tadhg - CORNELL UNIVERSITY|
|Shuler, M - CORNELL UNIVERSITY|
Submitted to: Journal of Natural Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 28, 1999
Publication Date: N/A
Interpretive Summary: Paclitaxel (Taxol) is a potent chemotherapeutic drug with potential against a range of cancers. The very limited supply of this drug from the original source, Pacific yew bark, however, prompted the development of alternative sources of production, including the use of plant cell cultures. When cultures are induced by the chemical methyl jasmonate, significant amounts of paclitaxel, as well as a large amount of other related compounds, are produced. In this study, we have identified three additional taxanes which account for up to 60% of total taxanes in induced cell cultures. These compounds may be of use as semi-synthetic starting materials for taxol and related compounds.
Technical Abstract: Cell suspension cultures of Taxus canadensis rapidly produced paclitaxel (1) and other taxoids in response to elicitation with methyl jasmonate. We have previously shown that paclitaxel (1) was only one of several taxoids produced in response to elicitation and, during the culture cycle, accounted for a maximum of 20% of the total taxoids in a culture (1). Three other taxoids, of potential value in the synthesis of taxoid analogs have been isolated from cell cultures of Taxus canadensis and identified as 13-acetyl-9-dihydrobaccatin-III (2), baccatin-VI (3), and 9-dihydrobaccatin III (4). Of these metabolites, 9-dihydrobaccatin III (4) has not reported in any Taxus species, whereas 13-acetyl-9-dihydrobaccatin-III (2) and baccatin-VI (3) have been isolated from a number of natural sources. This paper describes the 2D NMR techniques, mass spectrometry and partial synthesis used to rigorously elucidate the structure and stereochemistry of fthese natural products.