Seasonal Changes in the Concentration of Major Taxanes in the Biomass of Wild Canada Yew (Taxus canadensis. Marsh.)

Abstract

Seasonal variations in taxane concentrations in Taxus canadensis Marsh. (Canada yew) were measured at 15 sampling dates from September 2004 to September 2005 by clipping 3-year-old shoots from the same 15 plants. Four age classes of needles and stems were separated and individually weighed and analyzed for the three major taxanes in T. canadensis: 10-deacetylbaccatin III (10-DAB III), 9-dihydro-13-acetylbaccatin III (9-DHAB III), and paclitaxel (PAC). The dry weight fraction of each foliage age class decreased with increasing age; that is, proportionately more young than old foliage (current > current + 1 year > current + 2 year) was present in a 3-year-old stem. The ratio of needle:stem dry weight also decreased with increasing foliage age. Taxane concentrations varied widely, depending on the tissue, its age, and time of year. Peak concentrations were observed for a short period at the end of the growing season (August-September). The lowest taxane levels were found during the period of active growth: April through July. PAC and 9-DHAB III concentrations were higher in needles, but young stems contained the highest amounts of 10-DAB III. Levels of all three taxanes were higher in young than in old stems, likely due to increasing amounts of taxane-poor stem wood. Composite taxane concentrations were calculated for 3-year-old foliage from the component needle and stem weights and taxane analyses. It is suggested that summer harvesting between April and July (the low point in annual taxane levels) yields the poorest quality biomass, and harvesting from August onward is preferable.

Isolation and characterization of Stemphylium sedicola SBU-16 as a new endophytic taxol-producing fungus from Taxus baccata grown in Iran

“…Additionally, extraction of taxol from yew trees requires a complex system and specific purification techniques using advanced and expensive technology. Taking into account the facts mentioned above together with the seasonal variation in taxane concentration in Taxus (Cameron & Smith, ) and the ever increasing demand for the drug, there is an urgent need to find other alternative sources of production. Several methods have been developed for taxol production, for example, total chemical synthesis (Holton et al ., , b; Nicolaou et al ., ), semi‐synthesis from its precursor (Holton et al ., ), and plant tissue cell culture (Zhong, ).…”

“…Plant tissue cell culture is an environmentally sustainable source of taxol and offers several advantages as it is not subjected to weather, season, or contamination (Expósito et al ., ). However, these empirical methods have not been able to meet the increasing world demand for taxanes: 400 kg of taxol is currently needed in the USA and Europe every year (Cameron & Smith, ). Ultimately, to lower the price of taxol and increase its availability, a fermentation process involving a microorganism would be the most desirable means of supply.…”

Establishing a sustainable harvest for canada yew (Taxus canadensis marsh.) in Ontario

“…Increased light availability also increased the proportion of stem tissue harvested (Table 3). These results are important for commercial harvests because total taxane concentrations are highest in the foliage and lowest in the woody stem tissue (Cameron and Smith 2008). Thus, increasing the amount harvested per plant or branch generally decreases the total taxane yield per unit of dry weight.…”

“…Spring harvest in Ontario is shorter, starting when snow has melted (late March to early April) but finishing by the end of May or early June when new growth starts. Harvesting companies in Ontario do collect some biomass in summer, but lower taxane concentrations in growing tissue (Cameron and Smith 2008) reduce its value (Cameron et al 2005).…”

Dataset of Targeted Metabolite Analysis for Five Taxanes of Hellenic Taxus baccata L. Populations

“…It has also been used extensively for the semi-synthesis of Taxotere, which shows a more efficient anti-tumor activity than taxol, as well as the analogue of PACL, cephalomannine Data 2020, 5, 22 2 of 6 (CEPH) [6,8]. Other taxanes that are collected from the Taxus species are baccatin III (BAC), brevifoliol and 9-dihydro-13-acetylbaccatin III (9-DAB III) [9].…”