NIS - libdoc.who.int - World Health Organization

Herba Polygoni avicularis
Powdered plant material
Greenish-brown. Fragments of the leaf epidermis with polygonal to sinuous
cell walls and numerous anisocytic stomata; fragments of leaves and stems
containing numerous calcium oxalate clusters, some of them very large;
groups of thick-walled fibres from the hypodermis of the stem; globular pollen
grains with smooth exine and 3 germinal pores; occasional brown fragments
of the exocarp composed of cells with thick sinuous walls.
General identity tests
Macroscopic and microscopic examinations, thin-layer chromatography
for the presence of characteristic constituents, caffeic acid and chlorogenic
acid (1) or flavonoids (29), and colour reaction of cut drug with aluminium
chloride for the detection of flavonoids (2) and colour reaction of
water extract of pulverized drug with ferric chloride (30).
Using a 675 g/l solution of potassium hydroxide and gently heating,
the epidermis of the leaves and a few cells of the mesophyll stain red to
reddish-violet when examined using a 0.1 g/l solution of ferric chloride,
some leaf fragments stain almost black (1, 2, 7).
Purity tests
Microbiological
Tests for specific microorganisms and microbial contamination limits are
as described in the WHO guidelines on quality control methods for medicinal
plant materials (31).
Chemical
No information available.
Foreign organic matter
Not more than 2% of roots and not more than 2% of other foreign matter
(1, 2). Brownish and blackish parts of plant, not more than 3%. For cut
drug: not more than 10% of fragments of drug having a diameter less than
0.5 mm and not more than 10% of fragments of drug having a diameter
more than 7 mm (2). Not more than 3% (30).
Total ash
Not more than 10% (1), 13% (2, 30).
Acid-insoluble ash
Not more than 3% (30).
331