Linum. U. S. (Br.)
Related entries: Oil of Flaxseed
"The ripe seeds of Linum usitatissimum Linné (Fam. Linaceae), without the presence or admixture of more than 3 per cent. of other seeds or foreign matter. Preserve it in tightly-closed containers and add a few drops of carbon tetrachloride or chloroform from time to time to prevent attack by insects." U. S. "Linseed consists of the dried ripe seeds of Linum usitatissimum, Linn." ".
Lini Semina, Br.; Semence de Lin, Fr. Cod.; Grains de Lin, Fr.; Semen Lini, P. G.; Leinsamen, Flachssamen, G.; Lino, Semi di Lino, It.; Lino (Semilla de), Linaza, Sp.
Off. Prep.—Lini Semina Contusa, Br.; Species Emollientes, N. F.
Linum catharticum L. Purging Flax.—Purging flax is an European annual of the Fam. Linaceae, six to eight inches high. The whole plant is very bitter and somewhat acrid, and imparts its virtues to water, which acquires a yellow color. It appears to owe its activity to a peculiar drastic principle, which has received the name of linin, and which is afforded most largely by the plant after the flower has fallen. Schroeder (N. R. Pharm., xi, 11) obtained it in lustrous, white, silky crystals, which are neutral in reaction and have a strong persistent bitter taste in alcoholic solution. Purging flax has enjoyed some reputation in Europe as a gentle cathartic, useful in muscular rheumatism, catarrhal affections, and dropsy with disease of the liver. Dose, of the extract, from four to eight grains (0.26-0.5 Gm.); of the powder, one drachm (3.9 Gm.).
Lini Semina Contusa. Br.
"Crushed Linseed is Linseed reduced to a coarse powder. It should be recently prepared."
Linum Contusum, Br. 1898; Crushed Flaxseed.
Common flax is an annual plant, with an erect, slender, round stem, about two feet in height, branching at top, and, like all other parts of the plant, entirely smooth. The leaves are small, lanceolate, acute, entire, of a pale-green color, sessile, and scattered alternately over the stem and branches. The flowers are terminal, and of a delicate-blue color. The calyx is persistent, and composed of five ovate, sharp.. pointed, three-nerved leaflets, which are membranous on their border. The petals are five, obovate, striated, minutely scalloped at their extremities, and spread into funnel-shaped blossoms. The filaments are also five, united at the base, and the germ, which is ovate, supports five slender styles, terminating in obtuse stigmas. The fruit is a globular capsule, about the size of a small pea, having the persistent calyx at the base, crowned with a sharp spine, and containing ten seeds in distinct cells. This highly valuable plant, now almost everywhere cultivated, is said by some to have been originally derived from Egypt, by others from the great elevated plain of Central Asia. It flowers in June and July, and ripens its seed in August.
The flax plant was cultivated for its fiber by the American colonists soon after the landing of Columbus. Soon thereafter it was grown for its seed and already in 1792 the United States exported nearly 300,000'' bushels of .flaxseed. Very early the linseed oil industry was developed in the United States and in 1810 there were nearly 300 linseed oil mills in the 14 states, more than half of them being in Pennsylvania. It is estimated that at the present time 12,000,000 bushels of seed are crushed annually for the oil. "The annual crop of flaxseed in the United States approximates 30,000,000 bushels. A large quantity of seed is annually exported as well as oil-cake, the latter being extensively used as a cattle food.
Properties.—The official description of flax-seed is as follows: "Ovate or oblong-lanceolate, flattened, obliquely pointed at one end, from 3 to 5 mm. in length; externally chestnut-brown, very smooth and shiny, the raphe extending as a distinct, light-yellow ridge along one edge; easily cut with the finger-nail; internally olive-green; oily; odor slight; taste mucilaginous and oily. Under the microscope, transverse sections of Linseed when mounted in hydrated chloral T.S. show an epidermis with a mucilaginous layer from 0.01 to 0.03 mm. in thickness, covered by a very thin layer of cutin which is often more or less broken; two layers of parenchyma which overlie a continuous ring of stone cells having yellowish, porous walls and rather large lumina; a pigment layer, the cells having a reddish-brown .content; an endosperm consisting of from 6 to 10 rows of cells surrounding the two large plano-convex cotyledons; the cells of both the endosperm and the cotyledons contain a fixed oil and aleurone grains, the latter being from 0.003 to 0.02 mm. in diameter." U. S.
"Seeds small, brown, glossy, nearly flat; from about four to six millimetres long; ovate, somewhat obliquely pointed; surface glabrous and minutely pitted. Internally yellowish-white, with a narrow oily endosperm and two large oily cotyledons. Epidermal cells filled with mucilage which swells and dissolves in water. No odor; taste mucilaginous, oily." Br.
The linseeds in commerce have been divided by E. M. Hohnes into two groups. The first group, characterized by the seeds being of sufficient size for six or seven to weigh a grain, contains Bombay, Bold Calcutta, Sicilian, and Ionian seed; in the group of small seeds (10 to 12 to the grain) are English, Dutch, Russian, and ordinary Calcutta varieties. An important practical point noticed by Holmes is that much of the drug of commerce is adulterated with weed seeds, which are nearly always smaller than the linseeds, and can therefore be separated by the sieve. When linseed meal is to be made for medicinal use, this separation should always be insisted upon, as many of the weed seeds are from Cruciferae, and are irritating. For detailed information as to varieties of linseed, weed seeds, etc., the reader is referred to Holmes's paper. (P. J., July, 1881; also N. R., 1881.)
The ground seeds are found in commerce under the name of flaxseed meal. This is of a dark-gray color, highly oleaginous, and when mixed with hot water forms a soft adhesive mass, much employed for luting by practical chemists. "The powder of flaxseed is lemon-yellow or light brown, consisting chiefly of large, oily globules and irregular fragments of endosperm and seed-coat; the seed-coat is characterized by the tabular pigment cells filled with a reddish-brown, insoluble content and the somewhat elongated stone cells with yellowish walls; mounts made from material from which the fixed oil has been removed show aleurone grains from 0.003 to 0.02 mm. in diameter, both free and in the cells of the endosperm and embryo. Linseed Meal or Flaxseed Meal is light olive-brown with reddish-brown fragments; the latter being very coarse and the cellular tissues are the same as those of the powder. Powdered Linseed or Flaxseed and Linseed Meal or Flaxseed Meal must be free from any unpleasant or rancid odor. The powder, upon extraction with purified petroleum benzin, yields not less than 30 per cent. of a fixed oil, at least 98 per cent. of which is saponifiable. Boil 1 Gm. of the fat-free Linseed or Flaxseed Powder or Meal, with 50 mils of water, cool and filter; the filtrate gives not more than a faint blue color, on the addition of iodine T.S. Linseed yields not more than 6 per cent. of ash." U. S.
Crushed flaxseed is "a coarse, brownish-yellow powder, with readily visible fragments of the brown seed-coats. Bland, not pungent or rancid, odor when mixed with warm water. Yields not less than 30 per cent. of oil when exhausted by carbon disulphide; the oil thus obtained responds to the tests described under 'Oleum Lini'; the residual powder exhibits no starch grains when examined under the microscope. Ash not more than 5 per cent." Br.
The average composition of linseed oil cake is thus given by Schaedler (Technologie der Fette und Oele, 1883): moisture, 10.56 per cent.; oil, 9.83 per cent.; non-nitrogenous fiber, 44.61 per cent.; ash, 6.5 per cent.; proteid matter, 28.5 per cent.
Much of the linseed meal of commerce is simply cake meal, which was, indeed, official in the former Br. Ph., but such meal is unfit for medicinal use, not only because it contains very little oil, but also because the oil which is in it has, through rupture of the cells and partial expression, been so exposed to the air as to become rancid. Linseed meal is sometimes adulterated with corn meal, or other meals containing starch, whose presence is at once revealed by the iodine test. It is sometimes found in the market adulterated with petroleum or other mineral oil, doubtless made by powerfully pressing the pure linseed meal and substituting for the linseed oil the less expensive product, petroleum. (A. J. P., 1902, 31.)
The absolute value of a sample of crushed linseed can be determined by analysis. It should contain from 25 to 35 per cent. of oil, not more than 8 or 8.5 per cent. of husk, and less than 8 per cent. of ash. The following test is said to be sufficient for practical purposes: "Put half an ounce of the meal into a glass vessel, pour six ounces of boiling water over it, stir well, and allow it to stand for twelve hours. If first-class, it should absorb all the water, and show a thin scum of white glutinous liquid on the top, which will adhere closely to a glass rod or a wooden pencil dipped into it. If the meal does not absorb nearly all the water, it is of inferior quality. The amount of inferiority must be judged by the amount of water not absorbed, and by the character of the fluid on the top of the solution. If it is thin and non-glutinous, the meal is of inferior quality."
Meyer found in linseed fixed oil, wax, resin, extractive, tannin, gum, nitrogenous mucilage, starch, albumen, gluten, and various salts. Meurein could find no starch, but detected phosphates, which had escaped the notice of Meyer. (J. P. C., 3e ser., xx, 97.) For some years there has been a discussion concerning the reaction for starch which is sometimes ascertained in commercial flaxseed. Apparently starch grains are not usually present, although it is stated that they may occur in appreciable quantities in the unripe seed. (Ph. Ztg., li, p. 658.) Certain tissues of the seed coat beneath the mucilaginous epidermis may give a starch reaction, and it is stated that even the cells may contain starch. (Proc. A. Ph. A., 1907, lv, p. 326.) Their investing coat abounds in a peculiar gummy matter or mucilage, which is readily imparted to hot water, forming a thick viscid fluid, that lets fall white flakes upon the addition of alcohol, and affords a copious dense precipitate with lead subacetate. The viscid mucilage of linseed cannot be filtered until it has been boiled. It contains in the dry state more than 10 per cent. of mineral substances; when freed from these and dried at 110° C. (230° F.), it has, like althaea mucilage, the formula C12H20O10. The seeds by exhaustion with cold or warm water afford about 15 per cent. of this mucilage. By boiling with nitric acid, it yields crystals of mucic acid; by diluted mineral acids, it is broken up into dextrogyrate gum, sugar, and cellulose. (Kirchner and Tollens, Ann. Ch. Ph., clxxv, 215.) For further information on the histology and pharmacognosy of the flaxseed, see Winton and Moeller, "The Microscopy of Vegetable Foods;" Kate B. Winton, Bot. Gaz., lvii, p. 2445; Collin, J. P. C., 1909, xxix, p. 369.
Jorissen and Hairs (Drogues Simples, t. ii, 685) obtained from the young plant a glucoside, to which they gave the name of linamarin, which crystallizes in colorless needles, melting at 134° C. (273.2° F.), without odor, but possesses a fresh and bitter taste. It differs from amygdalin in not being decomposed by emulsin, but diluted acids decompose it into sugar, hydrocyanic acid, and a third product which is volatile and possesses certain of the characters of the acetones. No benzaldehyde is formed. Linseed contains about 4 per cent. of nitrogen, corresponding to about 25 per cent. of proteid substances. After expression of the oil these substances remain in the cake, so that the latter contains 5 per cent. of nitrogen and constitutes a very important article for feeding cattle and. is termed cake meal. The interior of the seed, or nucleus, is rich in a peculiar oil, which is separated by expression, and extensively employed in the arts on account of its drying properties. (See Oleum Lini.)
Uses.—Flaxseed is demulcent and emollient. The mucilage obtained by infusing the entire seeds in boiling water, in the proportion of half an ounce to the pint, is much and very advantageously employed in catarrh, dysentery, nephritic and calculous complaints, strangury, and other inflammatory affections of the mucous membrane of the lungs, intestines, and urinary passages. The whole seed is occasionally given in tablespoonful doses as a laxative. By decoction, water extracts a portion of the oleaginous matter, which renders the mucilage less fit for administration by the mouth, but superior as a laxative enema. The meal mixed with hot water forms an excellent emollient poultice.
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.