Effect of bulb age on alkaloid contents of narcissus pseudonarcissus bulbs

Narcissus is mostly grown for horticultural/decorative purposes in the fields and home gardens. Previously, galanthamine isolation (from the bulbs to produce medicine for the treatment of Alzheimer's disease) has been established as a novel use. Moreover, recent studies have also shown that Narcissus bulbs are also a source of several other interesting biologically active compounds and particularly some alkaloids. Various metabolites are produced at different time points during the growth cycle of plants. Also, for Narcissus bulbs it is important to find from an economical point of view the optimum time point for harvesting in its growth cycle, as the levels of galanthamine might be correlated with the age of the Narcissus bulbs. The aim of this study was to investigate the differences in the metabolites and specifically in the alkaloid contents based on a 1, 2- or 3-years harvesting cycle of Narcissus bulbs. Moreover, the effect of the cultivation site was studied for Narcissus pseudonarcissus cv Carlton which is well known for galanthamine production. Different methods were used for the analysis of these alkaloids. Untargeted NMR based metabolomics was used for overall metabolic changes and galanthamine quantitation. Whereas targeted GC-FID and GC-MS were used respectively for quantitative and qualitative analysis of major and minor alkaloids. An alkaloid specific acid-base extraction method was used in the GC-MS and GC-FID analysis. The results show that the contents of the metabolites vary significantly with the age of the bulbs. The contents of galanthamine were highest in two years old bulbs. It was also found that the alkaloid contents from the same variety grown at different locations differ from each other. Results presented here clearly indicate that] age of the bulb are important factors to consider for the industrial production of certain alkaloids from the plants as yields of alkaloids may vary, certain conditions may lead to an increase of the yield with 10-15%. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of SAAB.