NIS - libdoc.who.int - World Health Organization

WHO monographs on medicinal plants commonly used in the Newly Independent States (NIS)
late trichomes of the ovary (1–3, 31). According to the Österreichisches
Arzneibuch (32) and Pharmacopoeia Helvetica VII (33), adulterants can
be recognized microscopically by the densely pubescent bracts (e.g.
T. americana L. and T. tomentosa Moench), and/or by the flowers having
petalaceous staminodes (e.g. T. tomentosa).
Powdered plant material
Pale green powder; lower epidermis of bract has sinuous anticlinal walls,
striated cuticle, anomocytic stomata, stellate trichomes and glandular trichomes;
epidermal cells of petals elongated, straight anticlinal walls; mesophyll
with large cells containing mucilage which stains pink with ruthenium
red solution; cluster crystals of calcium oxalate; tetragonal pollen
grains with finely warty exine (3).
General identity tests
Macroscopic and microscopic examinations, thin-layer chromatography
for the presence of rutin, hyperoside, caffeic acid and other characteristic
constituents (2), and colour reaction of the cut drug with 5% ammonia
solution for the detection of flavonoids. If the cut drug is soaked for
3–5 minutes in cold water, the fragments of drug are mucilaginous to the
touch (1). The mesophyll has large cells containing mucilage, which stain
pink with ruthenium red solution (3).
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 (34).
Chemical
To be established according to national requirements. The German pharmacopoeia
(35) describes identification by detection of the flavonoids using
the Shinoda reaction, and also by separation by thin-layer chromatography
(6).
Foreign organic matter
Not more than 2% (2, 3). There should be no inflorescences with a bract
bearing at the abaxial face stellate, 5–8-rayed trichomes and flowers having
an apparent double corolla by transformation of 5 stamens into petal-like
staminoids and having a pistil which is not lobular nor indented. Hexamer-
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