Secondary metabolites from Taxus X media plant cell culture

Taxol (1) is a novel anti-cancer agent isolated from the Pacific Yew Taxus species. Effective activity against breast and ovarian cancer has been clinically proven, and led to Taxol being approved for marketing (Bristol-Myers Squibb Company) in 1992. However, Taxol's utility was limited not by safety or efficacy but by the lack of sufficient supplies of the therapeutic agent. Pacific Yew trees are scarce; to obtain only one gram of Taxol approximately 3-6 trees need to be harvested. Hence the intensive search for alternative methods to massproduce this precious anti-cancer agent. The main goal of my research was to examine the plant cell culture of Taxus x media for the production of secondary metabolites, especially for the production of Taxol and its simpler analogs that can, by semisynthetic routes be converted to Taxol. This thesis is based on two different types of experiments with the same culture: 1. Microferm experiments, where the culture was grown in bioreactors with mechanical stirring, and 2. Shake flask experiments, where the culture was grown in flasks placed on a rotary shaker. After extensive separation procedure, the secondary metabolites were isolated from the culture, and on the basis of spectroscopic data, the following structures could be assigned. Compounds 36 and 38 were isolated from the culture grown in the Microferm bioreactor. The culture grown in shake flasks produced compounds 36, 38, 39 and 40. It was found that the Taxus x media plant cell culture was not producing taxanes at levels measurable by our techniques. However, the culture was found to be stable and to give reproducible results in terms of metabolite production. We believe that further experiments with a combination of strategies, including nutrient and osmotic manipulations, gas composition effects, and elicitor treatments, to mention a few, would eventually lead to a Taxol and taxane producing cell line.Science, Faculty ofChemistry, Department ofGraduat