This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
The pomegranate tree, Punica Granatum, Linne (N.O. Lythrarieoe), is a shrub or small tree indigenous to Northwestern India, but cultivated generally in the warmer parts of the temperate regions, especially in the countries bordering on the
Mediterranean. More than one variety is known, but that producing crimson flowers is the commonest.
The vermifuge action of the pomegranate was well known to the ancients, who employed the juice of the fruit mixed with wine, as well as the small roots and a decoction of the root-bark. The drug appears to have been subsequently forgotten, but at the beginning of the present century its use among the Hindus attracted the attention of English physicians, and it began to be successfully employed. The bark of the root is said to be the most efficacious, especially when administered in the fresh state, but analyses have shown that the stem-bark is only slightly inferior in the proportion of alkaloid it contains (Ewers, 1899). The commercial drug usually consists of both.
Pomegranate bark occurs in irregular, curved or channelled pieces, varying usually from 5 to 10 cm. in length and from 1 to 3 cm. in width; it seldom forms quills.
The root-bark has a rough outer surface of an earthy yellow colour with darker patches and is marked with conchoidal depressions, due to exfoliation of the outer portion. The inner surface is smooth and yellow in colour, with irregular, darker, brown blotches. It breaks with a very short fracture, the fractured surface being nearly white and exhibiting under the lens numerous fine tangential and still finer radial lines.
The stem-bark differs from the root-bark in being smoother. It exhibits no conchoidal depressions, the formation of cork being less abundant, but it presents occasional, shallow, longitudinal furrows and bands of pale cork. Very frequently the minute apothecia of lichens can be detected on it; these are not to be found on the root-bark. The latter, too, is usually in more irregular, curved, flattish or even recurved fragments, whilst the stem-bark is in straighter, channelled pieces and sometimes in quills.
The bark of both stem and root is odourless, but has an astringent, slightly bitter taste.
The student should observe
(a) The short fracture and pale interior,
(b) The yellow colour of the inner surface with brown patches,
(c) The comparatively smooth surface of the stem-bark and the frequent presence of lichens,
(d) The rough surface, conchoidal depressions, and absence of lichens characteristic of root-bark.
Fig. 131. - Pomegranate root-bark. Transverse section. Magnified. (Berg).
The most important constituents of pomegranate bark are the alkaloids it contains. Four of these have been isolated (Tanret, 1878-1880); three, viz. pelletierine, isopelletierine, and methylpelletierine, are liquid, but pseudo-pelletierine is crystalline. These alkaloids exist to the extent of about 0.5 per cent, in the stem-bark, and 0.6 to 0.7 per cent, in the root-bark (Ewers, 1899). The average of commercial bark appears to be about 0.35 per cent. Carr and Reynolds (1908) found only 0.12 to 0.29 per cent.; other authorities give 0.5 to 0.7 per cent. The freshly dried bark has been found (in Java) to yield as much as 3.0 per cent., and indications are not wanting that the percentage of alkaloid diminishes on keeping.
Pomegranate bark contains further about 22 per cent, of gallotannic acid.
Pelletierine (C8H15NO) (Tanret, 1878) or punicine (Bender, 1885) is a colourless liquid boiling at 195°, but rapidly assuming a brown colour. Isopelletierine closely resembles it; methylpelletierine boils at 215°. Pseudopelletierine has also been called n-methylgranatonine (Cimician and Silber, 1893).
Pomegranate bark has an anthelmintic and slightly irritant action, but is somewhat astringent unless taken freely. It is used in the treatment of tapeworm, which is expelled (not actually killed) by the decoction, or by the sulphate of pelletierine.