Taxoids: Biosynthesis and in vitro production

Abstract

Taxoids viz. paclitaxel and docetaxel are of commercial importance since these are shown to have anti-cancerous activity. These taxoids have been isolated from the bark of Taxus species. There is an important gymnosperm, Taxus wallichiana(common name, ‘yew’) used for the isolation of taxoids. Due to cutting of the trees for its bark, population of the plant species are threatened to be endangered. Therefore, these are required to be protected globally. Plant cell culture techniques have been exploited for the isolation of mutant cell lines, production of secondary metabolites and genetic transformation of the plants. In vitro, culture ofTaxus not only helps in conservation but is also helpful in the production of paclitaxel and other taxoids. Various strategies tested globally for the commercial production of taxoids are discussed. Different Taxus species, their origin, diterpenoids obtained from different parts of the tree and their applications are discussed. Although, detailed taxoid biosynthetic pathway is not well known, an overview of the pathway has been described. Micropropagation of Taxus and regeneration of transgenic plants has been described. Although, several protocols have been reported for the production of some important taxoids, a rapid, reproducible and economically viable protocol required for the efficient production of taxoids has yet to be established. Supplementation of the biotic and abiotic elicitor(s) to the cell suspension cultures of Taxus has been shown to increase the growth of the cell biomass as well as paclitaxel production due to pathway stimulation. Up-scaling of Taxus cell lines capable of over-producing taxoids could only make the industrial production of paclitaxel feasible. Here, we have reviewedTaxus wallichiana cell cultures in terms of their capabilities of biomass and secondary metabolites production. Key words: Docetaxel, paclitaxel, taxanes, taxus.