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-C3units. 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.
