Dynamics of Growth and Galanthamine Biosynthesis in Hippeastrum papilio (Ravena) Van Sheepen Hydroponic Culture

Abstract

Hippeastrum papilio (Ravena) van Sheepen is a bulbous evergreen species and considered a potential new source of galanthamine. This natural compound approved by the FDA is used for the cognitive treatment of Alzheimer’s disease. To optimize the galanthamine yield from this species, it is necessary to study the effects of plant age and fertilization on the alkaloid content, as well as alkaloid and biomass accumulation dynamics in plant organs. H. papilio plants of different ages, which were ex vitro acclimatized (age 0) and previously grown for one (age 1) and two (age 2) vegetation seasons, were cultivated in a flood and drain hydroponic system with different fertilizer solutions for six months. Samples from the roots, bulbs, and leaves were gathered at the end of the vegetation, and the fresh and dry biomasses were measured and then analyzed by GC–MS to establish their alkaloid content. Depending on the age and fertilizer, the galanthamine content varied from 4.5 ± 1.8 to 11.2 ± 2.8 mg/g DW in the roots, from 3.4 ± 0.5 to 5.8 ± 1.3 mg/g DW in the bulbs, and from 3.2 ± 0.3 to 5.7 ± 0.6 mg/g DW in the leaves. The main part (53–61%) of galanthamine was accumulated in the bulbs, while the leaves and roots stored 25–30% and 13–19%, respectively. Higher amounts of N, K, and Ca in the fertilizer did not positively influence the alkaloid yield in plants of ages 1 and 2. Despite the lower biomass accumulation per individual, the plants grown for two seasons (age 1) showed a comparable galanthamine yield (per square meter) at the end of vegetation to those grown for three seasons (age 2) due to their higher density of cultivation. The dynamics of alkaloid and biomass accumulation, studied in plants from age 1 during the vegetation season, showed that the highest galanthamine content in the plant organs is at the beginning of vegetation. Still, the end of vegetation is the best time to harvest the plant biomass for galanthamine extraction. Hydroponic cultivation of H. papilio is an interesting alternative for the production of galanthamine.