WHO monographs on selected medicinal plants - travolekar.ru

<strong>WHO</strong> <strong>monographs</strong> on selected medicinal plants
Plant material of interest: dried stem, trunk or root bark
General appearance
Trunk bark: rough, 2–7 mm thick, plate-like or semi-tubular bark rolled
into large, tight cylinders. The outer surface is greyish white to greyish
brown, and rough, sometimes cork layer removed, and externally brown.
Inner surface smooth, light brown to purplish brown. Cut surface extremely
fibrous, light reddish brown to purplish brown (1, 3, 4). Stem
bark: quilled or double-quilled, 30–35 cm long, 2–7 mm thick, commonly
known as tongpu. Root bark: quilled singly or irregular pieces some
curved like chicken intestine, commonly known as jichangpo (2).
Organoleptic properties
Odour: aromatic; taste: pungent and slightly bitter (1–4).
Microscopic characteristics
Transverse section reveals a thick cork layer or several thin cork layers.
The outer surface of the cortex shows a ring of stone cells and scattered
on the inner surface are numerous oil cells and groups of stone cells. Phloem
rays 1–3 cells wide; fibre groups, mostly several in bundles, scattered.
Bast fibre groups lined stepwise between the medullary rays in the secondary
cortex. Most of the oil cells are scattered in the primary cortex,
with small numbers scattered in the secondary cortex, but some can also
be observed in the narrow medullary rays (1–4).
Powdered plant material
Yellow-brown powder consisting of a yellowish to red-brown cork layer;
stone cells of various sizes or groups; numerous fibres, 12–32 μm in diameter,
walls strongly thickened, sometimes undulate or serrate on one side, 1ignified,
pit canals indistinct; oil cells containing a yellowish-brown to red-brown
substance; single starch grains of about 10 μm in diameter and 2- to 4-compound
starch grains, and parenchyma cells containing starch grains (1, 2, 4).
General identity tests
Macroscopic and microscopic examinations (1–4), microchemical test (4)
and thin-layer chromatography (1–3).
Purity tests
Microbiological
Tests for specific microorganisms and microbial contamination limits are
as described in the <strong>WHO</strong> guidelines on assessing quality of herbal medicines
with reference to contaminants and residues (12).
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