Liquorice – Source, diagnostic characters, constituents and uses

Liquorice

Source, diagnostic characters, constituents and uses

Objectives

At the
end of this lecture, student will be able to

• Steroidal Saponins

Source,
diagnostic characters, constituents and uses of Liquorice

Steroidal Saponins

• Medicinally and commercially important

• Aglycone – soap like action

• Foamin property, colloidal solutions

• Haematotoxic- cause haeolysis; used as fish poisons

• Non crystalline, soluble in water and alcohol, insoluble
in organic solvents

• Aglycone – Sapogenin

• Harmful sapogenin – sapotoxins

• Steroidal saponins (Tetracyclic triterpenoid saponins)

– Raw material for various medicinally useful steroids

• Pentacyclic triterpenoid saponins

• Aglycone + sugars or uronic acid

• Sapogenin types – α-amyrin, β-amyrin
and lupeol

Liquorice

Synonym

• Glycyrrhiza, Glycyrrhizae radix, Mulethi

Source:

• Dried roots and stolons of Glycyrrhiza glabra
and other species of Glycyrrhiza

Family

• Leguminosae

Cultivation and Collection

• Propagation– vegetative, stolon with 2-3 buds

• Deep sandy soil, well prepared, farmyard manures added

• Stolon planted in March

• Fertilizers applied during the development of green parts

• Crops kept weed free

• Roots dug after 3-4 yrs in October

• Buds, rootlets removed

• Washed, dried in sun, then under shade

Morphology:

• Condition: Dry, occurs in peeled or unpeeled form

• Shape: Straight, nearly cylindrical (unpeeled) or angular
(peeled)

• Surface:  Yellowish
brown with longitudinal wrinkles (unpeeled), peeled one are yellow coloured
with fine longitudinal ridges. In case of stolons, scars of buds can be seen

• Size: 20-50cm long and 1-2cm in diameter

• Fracture:  Coarsely
fibrous in bark region and splintery in wood

• Odour: Characteristic, Taste: Sweet

Microscopy

Powder characters

Organoleptic characters: Taste, Colour, odour, taste

• Fibres

• Calcium oxalate (twin prisms)

• Wood elements

• Starch grains

Constituents

Triterpenoidal saponin glycosides – Glycyrrhizin
(3-9%), which is calcium and potassium salt of glycyrrhizinic acid

– Glycyrrhizinic acid on hydrolysis yields Glycyrrhetinic
acid

• Bitter principle: Glycyramarin

• Flavonoid Glycosides: Liquiritin, Isoliquiritin,
Liquiritigenin, Isoliquiritigenin

• Asparagin, fat

Test

• Thick section or powder + 80% sulphuric acid – deep
yellow colour

Varieties

G. glabra var. typica – Spanish liquorice

G. glabra var.glandulifera – Russian liquorice

G. glabra var. violacea – Persian liquorice

• Machurian liquorice – G. uralensis

Uses:

• Demulcent (Soothing), Sweetening agent

• Expectorant

• Treatment of Peptic ulcer, Spasmolytic agent

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