2.6.3 Linseed
Synonym Flax seed.
Biological Source It
consists of the dried fully ripe seeds of Linum usitatissimum Linn. Belonging
to family Liliaceae.
Geographical Sources It
is cultivated extensively as a source of fibres in Algeria, Egypt, Greece, Italy
and Spain; as a source of oil in Afghanistan, India and Turkey; and in Russia
(now CIS – countries) for both oil and fibre. It is also found in several
temperate and tropical zones.
Preparation The cyanogenetic
glycoside linamarin is prepared from the defatted oil meal, seedskins
or embryos of flax by standard methods available for glycosides.
Description
Colour : Reddish brown
Odour : Characteristic
odour
Shape : Oval and
strongly flattened
Size : Length = 4-6 mm;
Width = 2-3 mm.
Chemical Constituents The
ripe seeds of linseed contain small quantitites of a cyanogenetic glycosides
known as linamarin (or phaseolunatin) as given below:
Interestingly, linamarin evolved
HCN with linseed meal only but not with emulsin. However, pure linamarin is a
bitter needle like crystalline substance. It is freely soluble in water, cold
alcohol, hot acetone, slightly in hot ethyl acetate, ether, benzene, chloroform
and practically insoluble in petroleum ether.
Besides, linseed seeds comprise
of fixed oil (33-43%) mucilage present in testa (6%), proteins (25%) and an
enzyme called linase.
Linamarin upon
enzytmatic hydrolysis yields HCN which actualy renders the seeds highly poisonous.
Chemical Test The
mucilage of linseed seed gives a distinct red colour on being treated with Ruthenium
Red Solution.
Uses
1. Therapeutically, the linseed
oil is mostly recommended for the external applications only; liiments and
lotions.
2. It is employed in the
treatment of scabies and other skin disease in combination with pure flowers of
sulphur.
3. As the linseed oil has an
inherent very high ‘iodine value’ it is used mostly in the preparation
of non staining ‘Iodine Ointment’ and several other products such as: ‘Cresol
with Soap’.
4. Commercially, it is one of
the most important ‘drying oil’; and, therefore, substantially huge amounts
are exclusively used for varnishes and paints.
5. Linseed oil finds its
extensive application in the manufacturer of soap, grease, polymer,
plasticizer, polish and linoleum.
Source: Pharmacognosy And Pharmacobiotechnology By Ashutosh Kar
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