LINSEED OIL- Flax seed.

: In this ppt the viewers will come to know about Linseed Oil that is one of the Lipid containing crude drugs obtained from the plant sources Linseed is the dried, ripe seed of Linum usitatissimum Linn. Linseed oil is obtained by expression of linseeds, belonging to family Linaceae. This drug becomes important since it is obtained from fruit source. Here the synonyms, biological sources (scientific names & Family), geographical sources (what are the countries where it can be collected), chemical constituents, identification tests and uses has been discussed in brief.

1. LINSEED OIL BY Dr. Jitendra Patel Associate Professor AIPS, Hyderabad, India.

2. Synonyms Flax seed , Alsi ( Hindi).

3. Biological Source Linseed is the dried, ripe seed of Linum usitatissimum Linn. Linseed oil is obtained by expression of linseeds, belonging to family Linaceae .

4. Geographical Source Linseed is cultivated in many sub-tropical countries such as South America, India, United States, Canada, England, Russia , Greece, Italy, Spain, and Algeria.

5. Collection Linseed in an erect annual herb, 60–120 cm high with sky-blue flowers, and a globular capsule . The plant is cultivated for its seeds and fibre (flax ). A moderate rainfall is best suited for its growth . It grows in almost all types of soils where sufficient moisture is available, but thrives best in heavy soils with high moisture retaining capacity. As a mixed crop it is sown either on the margins of fields or in rows alternating with the other crop . Nitrogenous fertilizers yield better crop . The crop is harvested in February and March before the capsules are dried . Plants are cut close to the ground, dried in the field, and threshed to separate seeds.

6. Morphology of Seeds The seeds are oval, flattened, elongated, 4–6 mm long, and 2–3 mm wide. Testa is glossy, smooth, reddish-brown with minutely pitted surface. Seeds are rounded at one end . The other end is obliquely pointed where the hilum and micropyle are present in a slight depression . Raphe is present along one edge. Endosperm is narrow and encircles the embryo . It consists of two thick flattened, plano -convex cotyledons , and a radicle . The seeds art odourless but possess an oily and mucilaginous taste.

7. Preparation The dried seeds are crushed in rollers, moistened and heated to 80–90°C in steam to soften the seed tissues . They are then pressed through hot hydraulic press at a high pressure. The oil so obtained is treated with alkali to separate free fatty acids and bleached with fuller’s earth or charcoal . On cooling the oil waxy substances are removed. Linseed oil is a yellowish liquid, with a peculiar odour and bland taste . On exposure to air it gradually thickens, becomes darker and acquires a more pronounced odour and taste . On drying it forms a hard varnish. It has a high iodine value (~170) which indicates the presence of excess amount of glycerides of unsaturated fatty acids . The oil is slightly soluble in alcohol, miscible with chloroform, ether, petroleum ether, carbon disulphide, and terpentine oil . It has density 0.925–0.935, viscosity 1.47, congealing point ~20°C , saponification number 187–195, refractive index 1.47–1.48 , and unsaponifiable matters not over 1.5 %. A water-soluble resinous matter with antioxidant properties has been isolated from the oil.

8. Chemical constituents Linseed contains fixed oil (30–40%), mucilage (6–10 %), protein (25%) ( linin and colinin ), small amount of enzyme lipase , and linamarin which is a cyanogenetic glycoside. The carbohydrates present are sucrose, raffinose , cellulose, and mucilage . Linamarin is a glucose either of acetone cyanohydrin and is identical to phaseolunatin . Unripe seeds contain starch which is converted to mucilage on ripening the seeds. The mucilage can be fractionated into a neutral fraction a remified , arabinoxylan composed of D- xylose , L- arabinose , D-glucose and D- galactose ; and an acidic fraction mainly com posed of L- rhamnose and D- galactose . Mucilage swells with water and forms red colour with ruthenium red. Linamarin on hydrolysis yields acetone, hydrocyanic acid, and glucose. The other constituents are phytin , lecithin, wax, resin, pigments, malic acid, cyanogenic glycosides linustatin neolinustatin , and secoisolariciresinol and phenylpropanoid glucoside linusitamarin . On hydrolysis Linseed oil produces unsaturated acids like linolenic acid (30–50%), linoleic acid (23–24%), oleic acid (10–18 %) together with saturated acids- myristic , stearic , and palmitic (5–11%).

9. Uses Linseed is used as demulcent and in form of poultices for gouty and rheumatic swellings. Internally it is used for gonorrhoea and irritation of the genito -urinary system . Linseed oil has emollient, expectorant, diuretic, demulcent, and laxative properties and is utilized externally in lotions and liniments . Nonstaining iodine ointment soap, linoleum , greases, polishes, polymers, varnishes, paints, putty , oil cloths, printing inks, artificial rubber, tracing cloth , tanning and enamelling leather, etc. are also prepared from Linseed oil. The mucilaginous infusion is used internally as a demulcent in colds, coughs, bronchial affections, inflammation of the urinary tract, gonorrhoea, and diarrhoea.

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