Squill

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Chapter: Pharmacognosy and Phytochemistry : Drugs Containing Glycosides

Squill consists of the dried slices of the bulb of white variety of Urginea maritima (Linn.) Baker, belonging to family Liliaceae.


SQUILL

 

 

Synonyms

 

Scillae Bulbus, Squill, Scilla Bulb, White Squill, European Scilla, Urginea scilla, Drimia maritime.

 

Biological Source

 

Squill consists of the dried slices of the bulb of white variety of Urginea maritima (Linn.) Baker, belonging to family Liliaceae.

 

Geographical Source

 

It is mainly found in Spain, Portugal, Morocco, Algeria, Corsica, southern France, Italy, Malta, Dalmatia, Greece, Syria and Asia.

 

Cultivation and Collection

 

The plant prefers light (sandy) and medium (loamy) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It requires dry or moist soil. The plant can tolerate strong winds but not maritime exposure. Seeds are sown as soon as it is ripe in a greenhouse. The seeds were sown thinly so that the seedlings can be left in the pot for their first growing season. Fertilizers are to be used regularly. Once the plant becomes dormant the young bulbs are divided, placing two to three bulbs in each pot. After an year they are transplanted to the field. Division of offsets is done in late summer when the bulb is dormant. Larger bulbs can be replanted immediately into their permanent positions. It is probably best to pot up smaller bulbs and grow them on in a greenhouse for a year before planting them out when they are dormant in late summer.

 

The bulb is large and 18–20 cm high with 12 cm to 15 cm in diameter. Bulbs are dug out from the soil in the end of August and external scaly leaves and central portion are removed. The slices are dried completely in the sunlight or by heat of the stove. The drug is stored in airtight and especially in moisture proof containers.

 

Characteristics

 

It is a perennial plant with fibrous roots proceeding from the base of a large, tunicated, nearly globular bulb, 4–6 inches long, the outer scales of which are thin and papery, red or orange-brown in colour. The bulb, which is usually only half immersed in the sand, sends forth several long, lanceolate, pointed, somewhat undulated, shining, dark-green leaves, when fully grown, feet long. From the middle of the leaves, a round, smooth, succulent flower-stem rises, from 1 to 2 feet high, terminating in a long, close spike of whitish flowers, which stand on purplish peduncles, at the base of each, is a narrow, twisted, deciduous floral leaf or bract.

 

The undried bulb is somewhat pear-shaped, and generally about the size of a man’s fist, but often larger, weighing from 1/2 lb to more than 4 lb It has the usual structure of a bulb, being formed of smooth juicy scales, closely wrapped over one another. It has little odour, but its inner scales have a mucilaginous, bitter, acrid taste, owing to the presence of bitter glucosides. The dried slices are narrow, flattish, curved, yellowish-white, or with a roseate hue, according to the variety of squill from which they are obtained, from 1 to 2 inches long, more or less translucent.

 


                (a) Squill bulb, (b) Dried slice of squill bulb


Chemical Constituents

 

Squill contains cardiac glycosides of bufadienolides types, scillaren A and B and enzyme scillatenase. The other con-stituents present are glucoscillaren A (cardiac glycoside), proscillaridin A, flavonoid, mucilage, volatile substances and sinistrin. The cardiac glycoside (glucoscillaren A) on hydrolysis gives three glucose molecules, 2 molecules of glucose and a molecule of rhamnose along with scillarenin. Scillaren A is crystalline and responsible for the activity of the drug. Scillaren B is amorphous and its exact chemical structure is not known. Scillaren-A on hydrolysis with enzyme yields proscillaridin A and glucose. Proscillaridin A on further acid hydrolysis yields the aglycone scillarenin A and rhamnose. If scillaren A is hydrolysed with acid directly scillarenin A and an intermediary disaccharide scillabiose are obtained; Scillabiose on hydrolysis yields glucose and rhamnose.

 


 

 

Chemical Tests


1. They show negative results for Baljet test and Legal test.

 

2. The Lieberman’s sterol test is positive in squill gly-cosides.

 

3. In the mesophyll region of squill, mucliage, calcium oxalate and yellow colouring matter xanthoscillide are present. Mucilage does not give colour reaction with ruthenium red but stains red with corallin soda and pale yellow with iodine.

 

Uses

 

It is largely used for its stimulating, expectorant and diuretic properties, and is also a cardiac tonic, acting in a similar manner to digitalis, slowing and strengthening the pulse, though more irritating to the gastrointestinal mucous membrane. It is considered most useful in chronic bronchitis, catarrhal affections and asthma. It is a potential substitute for foxglove in aiding a failing heart.

 

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