Ispaghúl Seeds, Spogel Seeds.
Botanical Origin—Plantago decumbens Forsk. (P. Ispaghula Roxb.),[1795] a plant of variable aspect, from an inch to a foot in height, erect or decumbent, with linear lanceolate leaves which may be nearly glabrous, or covered with shaggy hairs. The flower-spikes differ according to the luxuriance of the plant, being in some specimens cylindrical and 1½ inches long, in others reduced to a globular head. The plant has a wide range, occurring in the Canary Islands, Egypt, Arabia, Beluchistan, Afghanistan, and North-western India. Stewart[1796] says it is common in the Peshawar valley and Trans-Indus generally up to 2000 feet; also on the plains and lower hills of the Punjab, but that he has never seen it cultivated in the latter region. It is said to be cultivated at Multan and Lahore, also in Bengal and Mysore.
History—The seeds which are found in all the bazaars of India and are held in great esteem, are generally designated by the Persian word Ispaghúl; but they also bear the Arabic name Bazre-qatúná, under which we find them mentioned by the Persian physician Alhervi[1797] in the 10th century, and about the same period or a little later by Avicenna.[1798] Several other Oriental writers are quoted by Ibn Baytar[1799] as referring to a drug of the same name, which may possibly have included the seeds of other species, as Plantago Psyllium L. and P. Cynops, having similar properties, and known to have been used from an early period.
J. H. Linck, whom we mentioned in our article on Oleum Cajuputi ([p. 278]), described in 1719 the seed under notice, yet without knowing its name; it further attracted the notice of Europeans towards the close of the last century,[1800] and has been often prescribed as a demulcent in dysentery and diarrhœa. It was admitted to the Pharmacopœia of India of 1868.
Description—The seeds, like those of other species of Plantago, are of boat-shaped form, the albumen being deeply furrowed on one side and vaulted on the other. They are a little over ⅒ of an inch in length and nearly half as broad, and so light that 100 weigh scarcely three grains. Their colour is a light pinkish grey with an elongated brown spot on the vaulted back, due to the embryo, which at this point is in close contact with the translucent testa. From this brown spot the thick radicle runs to the top of the seed. The hollow side of the seed is also brown and partially covered with a thin white membrane.
The seeds are highly mucilaginous in the mouth, but have neither taste nor odour. Those of the allied P. Psyllium have nearly the same form, but are shining and of a dark brown hue.
Microscopic Structure—This can be best investigated by immersing the seed in benzol, as in this medium the mucilage is insoluble. When thus examined, the whole surface is seen to consist of polyhedral cells, separated by a very thin brown layer from the albumen, which on the back of the seed is only 70 mkm. thick. The albumen is made up of thick-walled cells, loaded with granules of matter which acquire an orange hue on addition of iodine. The two cotyledons adhere in a direction perpendicular to the bottom of the furrow; their tissue is composed of thin-walled smaller cells, containing also albuminous granules and drops of fatty oil.
If the seed is immersed in water, the cells composing the epidermis instantly swell and elongate, and soon burst, leaving only fragments of their walls. When examined under glycerin, the change is more gradual, and the outer walls of the cells yielding the mucilage display a series of thin layers, which slowly swell and disappear by the action of water. The mucilage is consequently not contained within the cells, but is formed of the secondary deposits on their walls, as in linseed and quince pips.
Chemical Composition—Mucilage is so abundantly yielded by these seeds, that one part of them with 20 parts of water forms a thick tasteless jelly. On addition of a larger quantity of water and filtering, but little mucilage passes, the greater part of it adhering to the seeds. The mucilage separated by straining with pressure does not redden litmus, is not affected by iodine, nor precipitated by borax, alcohol or ferric chloride. The fat oil and albuminous matter of the seed have not been examined.
Uses—A decoction of the seeds (1 p. to 70 p. of water) is employed in India as a cooling, demulcent drink. The seeds powdered and mixed with sugar, or made gelatinous with water, are sometimes given in chronic diarrhœa.