WHO monographs on selected medicinal plants - travolekar.ru

<strong>WHO</strong> <strong>monographs</strong> on selected medicinal plants
shows 1-layered epidermis, some epidermal cells elongate forming unicellular
hairs. Hypodermis single-layered. Cortex 8–14 layered, consisting
of oval to polygonal, thick-walled parenchymatous cells. Primary stele,
tetrarch to heptarch, enclosed by a single-layered pericycle and singlelayered
thick-walled cells of endodermis. Mature roots show 4–15 layers
of cork, 1–2 layers of cork cambium. Vessels vary in size and shape, some
cylindrical with tail-like, tapering ends; some drum shaped with perforation
on end walls or lateral walls. Tracheids cylindrical with tapering
pointed ends (1).
Powdered plant material
Dusty grey in colour. Groups of cork cell fragments, thick-walled parenchyma,
pitted vessels and aseptate fibres. Simple round to oval starch
grains, 25–105 μm in diameter (1).
General identity tests
Macroscopic and microscopic examinations, microchemical tests and
thin-layer chromatography (1, 2), and high-performance liquid chromatography–mass
spectrometry (11).
Purity tests
Microbiological
Tests for specific microorganisms and microbial contamination limits are
as described in the <strong>WHO</strong> guidelines for assessing quality of herbal medicines
with reference to contaminants and residues (12).
Foreign organic matter
Not more than 2% (1).
Total ash
Not more than 7% (1, 2).
Acid-insoluble ash
Not more than 3% (2).
Water-soluble extractive
Not less than 20% (1).
Alcohol-soluble extractive
Not less than 30% (2).
Loss on drying
Contains not more than 13% water (2).
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