Page 79 - phytochemistry II -pharmD general

Estimation of ergot alkaloids

The total ergot alkaloids can be determined in the powdered drugs or
pharmaceutical preparations by one of the following techniques:

1. Colorimetrically, based on that the blue color produced with using Van Urk's
reagent is concentration dependent. The absorbance is measured at 590 nm
and compared with a with a standard reference alkaloid.

2. Fluoremetrically, based on that the alkaloids are fluorescent.

Production of ergot alkaloids

Production in artificial culture media:

Tissue culture technique has been adopted for the commercial production of
ergot alkaloids .Some attempts produced only the clavine- type alkaloids that are
of less medicinal value.

Other experiments with certain Claviceps species elaborated good yield of
mixture of lysergic acid derivatives. Results of these latter experiments are of great
commercial significance; as the total lysergic acid amides and /or derivatives can
be easily hydrolyzed to give free lysergic acid that can be converted to ergonovine
by reaction with 2- aminopropanol.

Nux vomica alkaloids

Some Strychnos species (Family Loganiaceae) Strychnos nux- vomica and
Strychnos ignatii contain a number of dihydroindole alkaloids the most important
of which are strychnine and its dimethoxy- derivative brucine.

In Nux vomica the alkaloids are located chiefly in the seeds, but are also
present in the leaves, wood, bark and other organs of the plant in variable amounts.
Some of the alkaloidal content is in the form of N-oxides.

In the seeds strychnine is usually located in the inner parts of the endosperm,
while brucine occurs largely in the outer layers of the endosperm.

The total alkaloidal contents of Nux vomica varies from 0.2 to 5%; and for
pharmaceutical purposes the seed is required to contain not less than 1.2 % of

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