NIS - libdoc.who.int - World Health Organization

Radix Glycyrrhizae
Glycyrrhiza uralensis Fisch.
The roots and rhizomes are cylindrical, fibrous, flexible, 20–100 cm long,
0.6–3.5 cm in diameter, with or without cork. Externally reddish brown
or greyish brown, longitudinally wrinkled, furrowed, lenticellate, and
with sparse rootlet scars. Texture compact, fracture slightly fibrous, yellowish
white, starchy; cambium ring distinct, rays radiate, some with
clefts. Rhizomes cylindrical, externally with bud scars, pith present in the
centre of fracture (6, 7, 16, 17).
Organoleptic properties
Odour slight and characteristic (1, 6, 7); taste, very sweet (1, 6, 7, 13, 15, 17).
Microscopic characteristics
In transverse section the cork is thick, brown or purplish brown, formed of
several layers of flattened polygonal thin-walled cells; cortex of phelloderm
in root somewhat narrow, yellow fibres of parenchyma cells contain isolated
prisms of calcium oxalate; phloem, wide, yellow, traversed by numerous
wavy parenchymatous medullary rays, 1–8 cells wide and consisting of
numerous radial groups of fibres, each surrounded by a crystal sheath of
parenchyma cells. Each cell usually contains a prism of calcium oxalate and
layers of parenchyma alternating with sieve tissue, the latter occasionally
obliterated, appearing as refractive irregular structures; phloem fibres, very
long, with very narrow lumen and strongly thickened stratified walls which
are cellulosic in the inner part of the phloem and slightly lignified in the
outer; xylem, yellow, distinctly radiate; xylem rays, consisting of small pale
yellow parenchyma, groups of fibres similar to those of the phloem but
more lignified, and surrounded by crystal-sheath, tracheids, and large wide
lumen vessels, 80–200 µm in diameter, with thick yellow reticulate walls or
with numerous oval bordered pits with slit-shaped openings. Other parenchyma
cells contain small round or oval starch granules. Pith, only in rhizome,
dark yellow, parenchymatous. Root, with 4-arch primary xylem, no
pith and shows 4 broad primary medullary rays, radiating from the centre
at right angles to one another. In peeled liquorice, the cork, cortex, and
sometimes part of the phloem are absent (1).
Powdered plant material
Light yellow in the peeled or brownish yellow or purplish brown in the
unpeeled root. Characterized by the numerous fragments of the fibres
accompanied by crystal-sheath, the fibres 8–25 µm, mostly 10–15 µm, in
diameter; dark yellow fragments of vessels, 80–200 µm in diameter, containing
solitary prismatic crystals of calcium oxalate, free or in cells 10–
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