Secondary Metabolism in Taxus spp. Plant Cell Culture In Vitro

Abstract

Abstract The genus Taxus (yew) is a source of a number of high-value medicinal substances, particularly, paclitaxel (taxol)—a complex diterpenoid compound with a powerful antitumor action (trade name of Taxol®). Paclitaxel is one of the most efficient drugs in chemotherapy owing to its specific ability to suppress proliferation of tumor cells via stabilization of their microtubules. The world-wide demand for taxol is 800–1000 kg a year and these figures annually rise by 20%. The growing need for paclitaxel and its derivatives and the shortage of plant resources necessary for their production made compounds of the taxane group one of the most important objects for development of biotechnological methods of their production. Out of all the possible ways of taxol production (isolation from wild or plantation trees, total chemical synthesis or semisynthesis, use of yew cell cultures, techniques of metabolic engineering, and use of yew endophytic fungi), the most promising is industrial cultivation of Taxus spp. cell cultures. This review examines the papers dealing with investigation of secondary metabolism in dedifferentiated cells in vitro of various yew species and feasibility of industrial use of cell cultures for production of taxoids. We revealed a number of specificity of Taxus spp. cell cultures: (1) from a cytophysiological aspect—difficult initiation of cell cultures, their low growth characteristics, specific media and culturing conditions; (2) from a phytochemical aspect—distinction from intact plants in qualitative composition and content of secondary metabolites accounted for by specificity of cell culture as a biological system; predominant formation of С14-hydroxylated rather than of С13-hydroxylated taxoids; an opportunity for elevation of the content of taxoids—including commercially valuable ones (paclitaxel and baccatin III) with the aid of different tools (elicitation, stress exposures, two-phase cultivation and some others); (3) from a biotechnological aspect—possibility of industrial cultivation of yew cell cultures; existence of several successful industries (Germany and the Republic of Korea).