Integrating Narcissus-derived galanthamine production into traditional upland farming systems

Abstract

Alzheimer's disease (AD) is a disorder associated with progressive degeneration of memory and cognitive function. Galantamine is a licenced treatment for AD but supplies of the plant alkaloid that it is produced from, galanthamine, are limited. This three-year system study tested the potential to combine Narcissus-derived galanthamine production with grassland-based ruminant production. Replicate plots of permanent pasture were prepared with and without bulbs of Narcissus pseudonarcissus sown as lines into the sward. Two different fertiliser regimes were imposed. The above-ground green biomass of N. pseudonarcissus was harvested in early spring and the galanthamine yield determined. In the second harvest year a split-plot design was implemented with lines of N. pseudonarcissus cut annually and biennially. All plots were subsequently grazed by ewes and lambs and animal performance recorded. Incorporation of N. pseudonarcissus into grazed permanent pasture had no detrimental effects on the health or performance of the sheep which subsequently grazed the pasture. There was no consistency to the effects of fertiliser rates on galanthamine yields. There was no difference in overall galanthamine yield if N. pseudonarcissus was cut biennially (1.64 vs. 1.75 kg galanthamine/ha for annual combined vs biennial cuts respectively; s.e.d = 0.117 kg galanthamine/ha; ns). This study verified the feasibility of a dual cropping approach to producing plant-derived galanthamine.

Figure 1

View across experimental site showing Narcissus pseudonarcissus cv Carlton established under improved permanent pasture at 380 m a.s.l. at a sowing rate of 4 t/ha (Photo—M. Fraser).

Figure 2

Percentage of sampled flowers of Narcissus pseudonarcissus cv Carlton accounted for by different growth stages at point of harvest (where dark yellow = compound fertiliser applied at a rate of 50 kgN/ha, 25 kgP/ha and 25 kgK/ha; light yellow = compound fertiliser applied at a rate of 25 kg N/ha, 12.5 kg P/ha and 12.5 kg K/ha; error bars = s.e.m.).

Figure 3

Effect of fertiliser application and cutting history on (a) estimated biomass yields of Narcissus pseudonarcissus cv Carlton, and (b) corresponding galanthamine yields in 2018 (where cut = harvested the previous year; not cut = no harvest the previous year; Daff/full = compound fertiliser applied at a rate of 50 kgN/ha, 25 kgP/ha and 25 kgK/ha; Daff/half = compound fertiliser applied at a rate of 25 kg N/ha, 12.5 kg P/ha and 12.5 kg K/ha; error bars = s.e.d.).

Figure 4

Illustration of changes in sward nutritional parameters across seasons and years, (where green line = permanent pasture with fertiliser applied at a rate of 50 N kg/ha, 25 P kg/ha and 25 K kg/ha; dark blue line = permanent pasture under-sown with Narcissus pseudonarcissus, with fertiliser applied at a rate of 50 N kg/ha, 25 P kg/ha and 25 K kg/ha; light blue line = permanent pasture under sown with N. pseudonarcissus, with fertiliser applied at a rate of 25 N kg/ha, 12.5 P kg/ha and 12.5 K kg/ha; y = significant treatment effect of sowing N. pseudonarcissus (P < 0.05); z = significant treatment effect of rate of fertiliser application (P < 0.05); error bars = standard errors of the difference).