Feverfew (Tanacetum parthenium L): Tissue culture and parthenolide synthesis

Protocols are reported for the tissue culture of feverfew (Tanacetum parthenium L. Schultz-Bip.). Explants of the laminae from young, fully expanded leaves of glasshouse-grown plants regenerated shoots when cultured (50-60 days) on MS-based medium with 4.5 mg/l of both 6-benzylaminopurine and alpha-naphthaleneacetic acid. HPLC analysis of extracts of leaves and roots of cloned axenic plants, plants regenerated from leaf explants, seedling-derived leaves, leaf-derived calli and cell suspensions from pedicel-derived callus, revealed large variations in parthenolide content, from < 5.0 x 10(-3) % dry weight in cell suspensions to 1.72 +/- 0.04% dry weight (mean +/- S.D.; n = 5) in leaves of axenic shoots. Where possible, the corresponding organs from glasshouse-grown plants of the same isogenic line were also analyzed, and the mean parthenolide concentration in the apical leaves of this material (2.77 +/- 0.06% dry weight; n = 3) was more than twice the previously reported maximum for this species. An evaluation, over a 120-day period, of cloned axenic shoots revealed variation with time for individual cultures and also differences between cultures, in the parthenolide content of leaves (0.12-1.72% dry weight). Parthenolide accumulation in the leaves of axenic shoots could be increased from 0.06 +/- 0.01% to 1.92 +/- 0.26% dry weight (n = 5) by altering the carbon source in the culture medium.