NIS - libdoc.who.int - World Health Organization

Herba Leonuri
ing trichomes, uniseriate, composed of 2–8 cells with slight swellings at
the junctions and thick warty walls; glandular trichomes of the typical
Lamiaceae type with a short, unicellular stalk and a head composed of a
single cell, or less frequently, multicellular and rounded, composed of
4–8 cells; cortex narrow, parenchymatous with collenchyma at the ridges;
phloem narrow, thin-walled; xylem lignified with small, spirally and annularly
thickened vessels and groups of thick-walled fibres. Leaf: upper
epidermal cells of leaf straight-walled with a striated cuticle and scattered
large, rounded, diacytic and anomocytic stomata; lower epidermal cells
with sinuous walls and more numerous stomata; abundant covering and
glandular trichomes on both surfaces, particularly on the lower surface,
similar to those occurring on the stem, with both types of glandular trichomes
equally numerous. Flower: epidermal cells of the calyx with sinuous
anticlinal walls; mesophyll cells containing numerous small cluster
crystals of calcium oxalate; inner epidermis of the corolla with very numerous
covering trichomes similar to those occurring on the stem and
leaves; fibrous layer of the anther; pollen grains spherical, about 25–30 µm
in diameter, with 3 pores and 3 furrows and a smooth exine; occasional
brown fragments of pericarp with single crystals of calcium oxalate (1, 2,
28, 29).
Powdered plant material
Greenish-grey powder with a strong, aromatic odour and a bitter taste.
The powder has the same microscopic characteristics as the entire stem,
leaf and flower (see Microscopic characteristics) (28).
General identity tests
Macroscopic and microscopic examinations, luminescence microscopy
and thin-layer chromatography for the characteristic constituents, iridoids
and flavonoids (1, 2, 5, 28).
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 (30).
Chemical
No information available.
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