|Abstract or Summary
- A pharmacognostic study was made of the root of Heracleum
mantegazzianum, an umbelliferous species which is of value as a
source of natural coumarins.
Three groups of seeds were tested to determine the presence
of a germination requirement for moist cold and the possible value
of gibberellic acid in obviating this requirement. The first group of
seeds was cold-treated for 74 days at a range of from 2 to 5°C. The
second group of seeds was soaked for 20 hours in a solution containing
100 parts per million of gibberellic acid. The third group
of seeds, used as controls, was soaked in water. When planted and
maintained under greenhouse conditions only the cold-treated seeds
germinated. The germination rate was 10.3%. Both seeds treated
with gibberellic acid and the controls failed to germinate, showing
that a cold requirement does exist and that treatment with gibber-ellic acid will not substitute for the cold requirement. A fourth
group of seeds, cold- treated for 294 days, germinated at a rate of
approximately 55%, showing that germination is proportional to total
days of cold treatment.
Sequential selective solvent extraction with a series of increasing
polarity gave the following fractions as average percentages
of dry weight: petroleum ether, 2.4; ether, anhydrous, 2.5; ether
U.S.P., 2.0 alcohol 95%, 8.5; water, 19.4. Copious foaming of
the aqueous fraction showed the possible presence of saponins.
The description and histology of the whole root as well as the
character of the powdered root was recorded. Among diagnostic
characters of the powdered root are its blue coloration when moistened
with iodine water, a slight yellow fluorescence under ultraviolet
light turning to luminescence for several seconds following
extinction of the light, and the presence of numerous clustered
starch grains which gelatinize rapidly in chloral hydrate solution.
Thin-layer chromatography of the ether extract of the air-dried root on Silica Gel G showed seven principal spots fluorescing
under ultraviolet light. R[subscript f] values and colors corresponded to those
of six standard coumarins. The following coumarins are presumed
to be present: isobergapten, pimpinellin, bergapten, isopimpinellin,
sphondin and umbelliferone. The seventh spot was not identified.
The R[subscript f] values in two solvent systems and the fluorescent colors
under ultraviolet light are reported for the extract spots as well as for six coumarins.
Studies were also made to determine the relative stability of
coumarins to heat. Six standard coumarins as well as the extract of
the air-dried root were spotted individually on Silica Gel G plates
and developed two-dimensionally. Following development in the
first direction and prior to development in the second direction the
plates were exposed to a temperature of 65°C. for 30 minutes in an
oven. With the exception of sphondin the chromatograms of the
individual coumarins showed from one to two additional spots. This
indicates that coumarins as a group are subject to modification at a
temperature of 65°C.
Regular two-dimensional chromatography of the ether extract
of the root material which had been dried at 38°C. gave spots for
only five coumarins. It is concluded that the roots should be dried
only at the normal air temperatures.