Seed Germination Inhibitory Activity of Alkaloid Fractions from Narcissus pseudonarcissus cv. Carlton and Narcissus poeticus Leaves

Narcissus species have been cultivated for centuries around the world and are mainly used as cut flowers. Although the bulbs of these species have been widely examined as sources of alkaloids and biological activity, the leaves have been understudied. In the present study alkaloid fractions of leaves from Narcissus pseudonarcissus cv. Carlton and N. poeticus L. were evaluated for inhibitory activity against seed germination of Lolium perenne L. and Trifolium pratense L. Separately, the metabolic profiles from seedlings of the target species were analyzed after treatment with a lycorine solution. The composition of methanolic extracts from seedlings and alkaloid fractions of Narcissus leaves were determined using GC/MS. The N. pseudonarcissus alkaloid fraction was more active than that of N. poeticus. Complete inhibitory activity of the alkaloid fraction was established at a concentration of 1 or 2 mg/mL, depending on the target species. Lycoramine and galanthine were identified as the main alkaloids of N. pseudonarcissus. 8-O-Demethylmaritidine, maritidine and homolycorine were found to be the predominant alkaloids of N. poeticus. Increased accumulation of some amino acids, saccharides and polyols, indicating protein synthesis inhibition, was the most common response of target species seedlings treated with 0.17 µM lycorine. The results showed the promising potential of alkaloid fractions from the leaves of Narcissus species as seed germination inhibitors. The study contributes to full utilization of the resources of these species and presents, to our knowledge, for the first time data on changes in the metabolic profiles of L. perenne and T. pratense seedlings after treatment with lycorine.