Production of Anticancer Secondary Metabolites: Impacts of Bioprocess Engineering

Higher plants produce a wide spectrum of secondary metabolites that have been used as sources of a large number of industrial products (e.g. agricultural chemicals and pharmaceuticals). Although some of the natural products have been replaced by synthetic substitutes because of cost considerations, a number of medicinally important high value chemicals are still being extracted from plants. These products are used as intermediate/model compounds for chemical synthesis of many potent analogues/pharmaceuticals. Various natural products are used as antitumour agents or for the synthesis of antitumour agents. Of note, the readily available baccatin III have been exploited for the synthesis of paclitaxel by coupling baccatin III and the N-benzoyl-b-phenylisoserine side chain. However, novel biotechnological approaches (e.g. cell based bioprocess engineering) appears to be the best strategy since the extraction of natural products from plant sources may result in extinction of medicinal plant species (e.g. Taxus species). In fact, this approach confers cost-effective technology for the large-scale production of clinically/commercially important secondary metabolites such as paclitaxel. Since the emergence of the tissue culture technology in early 1950s, it has been increasingly advanced towards industrial production of secondary metabolites to overcome many problems associated with such approach. Given the fact that the plant cells/tissue culture systems not only provide means for biosynthesis of natural products but also serve as 'factories' for bioconversion of low value compounds into high value products, in the current chapter, we will focus on impacts of this robust technology regarding production of anticancer secondary metabolites.

Keywords: Secondary metabolites, natural products, cancer, antitumor, bioprocess engineering, largescale production, biosynthesis, semi-synthetic derivatives, biotechnology, precursor, cell culture, elicitation, immobilized biocatalysts.