Narcissus and Daffodil

Agronomic factors and galanthamine production 281
In order to reach maximum yields of galanthamine, bulb lifting might be early in
the spring, when meristematic activity is at a maximum. Harvesting in early spring
may reduce herbicide application and adulteration problems caused by weeds
in heavily infested fields. On the contrary, lifting dormant bulbs may facilitate
biomass-handling processes, but it will require post-harvest treatments to promote
bulb sprouting to enhance galanthamine yield.
CONSIDERATIONS AND PERSPECTIVES FOR SHORT-TERM
GALANTHAMINE PRODUCTION FROM NARCISSUS
The world’s largest producer of narcissus is the UK, with a production area of
about 4500 ha (Rees, 1992). Other major producers include the Netherlands, US
and Poland (Hanks, 1993). Narcissus ‘Ice Follies’ is a fast growing and popular
cultivar, ranking third in flower bulb sales according to the International Bulb
Society, Pasadena, California. In the Netherlands, the cultivated area of Narcissus
‘Ice Follies’ in 1998/99 was given as 101 hectares (Anon., 1999). However, no equivalent
data have been found on production areas of ‘Ice Follies’ in the other major
producer countries. Therefore, we have no information on the overall commercial
availability of bulbs of this cultivar, but as it is among the best selling cultivars one
can expect a reasonable amount of available stock with which to initiate pilot-scale
production. Additionally, ‘Ice Follies’ contains reasonable amounts of galanthamine:
the average content extracted from dormant bulbs is 70 mg per 100 g dry weight
(Moraes-Cerdeira et al., 1997b).
The recommended daily dose of galanthamine to treat an AD patient varies
between 30 and 50 mg (Dal-Bianco et al., 1991). Therefore, a single patient would
need around 20 g of galanthamine per year. Today, there are 4 million AD
patients in the US alone. To treat 30% of these patients with galanthamine hydrobromide,
24 000 kg of the compound would be required per year. Aiming for a
30% market is considered a standard goal for pharmaceutical companies to invest
into a new product.
Under Mississippi climatic conditions, Narcissus ‘Ice Follies’ produced 14 300 kg
of bulbs per hectare in one growing cycle (Moraes-Cerdeira et al., 1997b), representing
a growth increase of 70%. Based on this example of bulb production and
using commercial scale drug isolation of 65% efficiency, the cultivated area necessary
to treat 30% of the US patients in one year would be 10 018 ha. This estimated
area reflects the bulb yield of Narcissus ‘Ice Follies’ grown in Mississippi under suboptimal
climatic conditions (Anderson, 1989) and 36.82% dry weight of the fresh
bulbs with 70 mg of galanthamine per 100 g of dry biomass. Under the UK conditions,
narcissus bulbs are typically planted at a rate of around 17.5 t/ha, and a
weight increase of at least 120% would be expected for an average variety after two
years, a total yield of about 38.5 t/ha (Hanks, 1993). Such high-density plantings
would be a suitable growing system for a cheap cultivar with a low yield of galanthamine,
and on this basis an area of 13 636 ha would be needed to produce the
same amount of galanthamine as in the example above for ‘Ice Follies’ growing in
Mississippi, but for a two-year demand to treat 30% of AD patients. Using chipped
bulbs (eight chips per bulb) and planting 2 t of chipped bulbs per ha, a reasonable
expectation would be a nine-fold increase in weight and number of bulbs after two