: 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.

3. Synonyms
1. Flax seed,
2. Alsi (Hindi).

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

5. 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.

6. 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.

7. 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.

8. 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.

9. 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%).

10. 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.

11. Thank You