Narcissus and Daffodil

276 R.M. Moraes
bulbs of many Narcissus cultivars are available in commercial quantities, offering
the possibility of establishing large-scale cultivation for medicinal purposes in a
short time; secondly, a comprehensive body of information already exists regarding
narcissus propagation, physiology, breeding and cultivation for flower production
(e.g., Rees, 1992; Hanks, 1993). In this chapter, the results of studies on
planting density and depth, bulb size, and alkaloid distribution within the bulb
and at different stages of bulb development, are reported. Agronomically important
aspects of narcissus production for medicinal purposes will also be discussed.
AMARYLLIDACEAE FOR THE SUPPLY OF GALANTHAMINE
The present commercial sources for galanthamine are wild populations of Leucojum
and Galanthus. The sourcing and cultivating of medicinal species are requirements
for the progression of some natural products into pharmaceuticals.
Treatment of large patient populations requires a reliable supply of the active
compound at an affordable price. Therefore, the cultivation of medicinal plants is
a growing segment of the pharmaceutical industry, and there is an urgent need
for high-quality biomass from non-wild sources to benefit consumers and to protect
the environment. Palevitch (1991) has reported the advantages of medicinal
plant cultivation over collection from the wild. These are: quality products with
botanical source assurance, a stable market for consumers with increasing availability
of plant material, and less fluctuation in supply.
Extensive surveys seeking richer galanthamine sources have been carried out on
most of the Old World taxa of the Amaryllidaceae, but New World amaryllids,
especially the numerous neotropical genera, have rarely been examined. Poulev
et al. (1993) reported that Phaedranassa megistophylla, a species native to Peru, contains
7.4% galanthamine on a dry weight basis. It appears to be a very promising
source, since this concentration is several times higher than the highest concentration
reported for any other source of galanthamine.
Galanthamine is not only found in Amaryllidaceae sensu stricto: low concentrations
of galanthamine have been detected in the closely related families of
Agavaceae, Haemodoraceae and Hypoxidaceae using an enzyme immunoassay
procedure (Poulev et al., 1993). Using a different method (Bastos et al., 1996), most
of the findings of Poulev et al. (1993) have been confirmed, and in a survey of
Narcissus, more than 80 taxa were analysed. Extracts from dormant bulbs of
Narcissus ‘Inglescombe’ had the highest galanthamine content, 173.7 mg per 100 g
of dry weight (0.17%). A wide genotypically fixed variation in alkaloid content
among cultivars was found (Bastos et al., 1996; Moraes-Cerdeira et al., 1997b).
ALKALOID CONTENT OF DIFFERENT PARTS OF THE BULB
The importance of galanthamine as a therapeutic drug, and the biological value of
other narcissus alkaloids, prompted the study of the distribution of several alkaloids
in specific bulb parts (Moraes-Cerdeira et al., 1997a). Rees (1969) described
the narcissus bulb as a complex branching system composed of several ‘bulb units’.
Each bulb unit consists of a shoot apex enclosed by bulb scales and leaf bases acting