Alkaloid Extraction and Purification From Catharanthus roseus Hairy Root Tissue

Plant metabolic engineering of Catharanthus roseus may provide improved ways of producing vincristine (Oncovin®) and vinblastine (Velbe®) which are used in the treatment of cancer.  The tabersonine branch point is very important for the synthesis of vindoline which is a key precursor to vincristine and vinblastine.  Genetically modified C. roseus hairy root lines are used to analyze the flux of metabolites at the tabersonine branch point.  Genes inserted by recombinant DNA techniques can amplify or suppress flux through existing metabolic pathways and can create new metabolic pathways for desired products that are not expressed in the wild-type line.  By suppressing flux to undesired products like hörhammericine, tabersonine flux can be diverted to the vindoline-vinblastine-vincristine pathway.  One of the current research challenges is the lack of commercially available standards to quantify low-level metabolites at the tabersonine branch point.  A biomass extraction and analytical HPLC protocol was adapted for semi-preparative scale in order to obtain tabersonine, lochnericine, and hörhammericine standards from C. roseus hairy root tissue.  Standards will enable improved study of the metabolic pathways originating at the tabersonine branch point and will allow for the determination of previously unidentified co-eluting tabersonine-like compounds.