6. Podophyllum
Synonyms Podophyllum
resin; May apple; Mandrakes Root; Indian apple; Vegetable calomel.
Biological Sources
Podophyllum is the dried rhizomes and roots of Podophyllum peltatum L.,
family: Berberidaceae, known as American Podophyllum; and from Podophyllum
hexandrum Royle (Syn. P. emodi Wall. ex Hook. f. & Th.) usually
called Indian Podophyllum.
Preparation Extract
powdered podophyllum (1 killo) by means of slow percolation until it is almost
exhausted of its resin content, using ethanol as the menstruum. Carefully
concentrate the percolate by evaporation until the residue attains the
consistency of a thin syrup. Pour the resulting syrupy liquid with constant
stirring into 1 L of distilled water containing 10 ml of concentrated HCl and
previously cooled to a temperature less than 10°C. Allow the precipitate to
settle down completely, decant the clean supernatant liquid and wash the
precipitate with two 1000 ml portions of cold distilled water slowly, dry the
resin and powder it.
Characteristic Features It
is a light brown to greenish-yellow powder, or small, yellowish, bulky, fragile
lumps usually becoming darker in shade on exposure to either heat (> 25°C)
or light (uvrays).
It has a characteristic faint
odour and a bitter acrid taste. It is freely soluble in ethanol, usually with a
slight opalescence. It is also soluble in dilute alkaline solution. It is found
to be not less than 65% soluble in chloroform and 75% soluble in ether.
Chemical Constituents
Podophyllum contains 3.5 to 6% of a resin whose active principles are lignans,
which are essentially C18-compounds related biosynthetically to
the flavonoids, and are derived by dimerisation of two C6-C3
units. The most important ones present in the podophyllum resin, are
podophyllotoxin (20% in American Podophyllum) and in much higher
quantum almost upto 40% in Indian Podophyllum. Besides, it also contains
α-peltatin (10%) and β-peltatin (5%).
It is pertinent to mention here
that a host of lignan glycosides are also present in the plant, but by virtue
of their water-soluble properties, they are almost eliminated during the normal
preparation of the resin.
Interestingly, all the three
above mentioned chemical constituents are present both in free state and as
their respective glycosides. The Indian Podophyllum is devoid of α-and β-peltatins.
The resin also comprise of the closely related dimethylpodophyllotoxin and
its glycoside; and dehydropodophyllotoxin, as well as quercetin-a
tetra-hydroxy flavonol.
Chemical Tests
1. Podophyllotoxin (active
lactone) present in the resin when dissolved in alkali, cooled to 0°C and
subsequently treated with an acid it yields an unstable gelatinous podophyllic
acid.
2. The resulting podophyllic
acid when treated with dehydrating agents easily loses a molecule of water
and gives rise to picropodophyllin (inactive lactone), which
being an isomer of podophyllotoxin.
The resins obtained from the
American and Indian podophyllum are not quite identical and these two drugs of
the trade may be distinguished chemically as given below:
(a) Prepare an alcoholic
extract from each resin and filter. Add a few drops of strong solution
of cupric acetate 5% (w/v) to each of the above two filtrates. The American
podophyllum containing α-and β-peltatin produces an instant bright green
colouration, while the Indian podophyllum (devoid of peltatin)
fails this test.
(b) An alcoholic solution
of Indian podophyllum resin readily gelatinizes on being treated with
alkali hydroxide, while the American resin does not gelatinize. This is due to
the fact that the former contains podophyllic acid and it gives the
alkali salt of this acid which is gelatinous in nature.
Uses
1. It is used as a drastic but
slow-acting purgative.
2. Podophyllotoxin possesses
anti-tumour (antineoplastic) properties and may be used in the treatment of
cancer.
3. It is invariably prescribed
with other purgatives, henbane or belladonna to prevent gripping in infants.
Source:Pharmacognosy And Pharmacobiotechnology By Ashutosh Kar
Source:Pharmacognosy And Pharmacobiotechnology By Ashutosh Kar
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