WHO monographs on selected medicinal plants - travolekar.ru

Lichen Islandicus
bands, 0.3–1.5 cm wide and 0.5 mm thick, sometimes serrated with the
margin appearing ciliated (pycnidial) thick; lower surface pale greyish,
with scattered small, white, ovoid, depressed spots; occasional, dark reddish-brown,
cup-shaped, fruiting bodies (apothecia), about 6 mm in diameter,
on the upper surface (greenish to greenish brown) near the margins;
texture harsh, springy and brittle; on the apex of the terminal lobes,
very rarely, there are brown, discoid apothecia (1).
Organoleptic properties
Odour: none; taste: mucilaginous and distinctly bitter (1).
Microscopic characteristics
Cut transversely, branches show upper and lower colourless cortical regions
composed of closely-packed hyphae, appearing as small-celled pseudoparenchyma;
below the upper cortex, the algal or gonidial layer containing
numerous yellowish-green, subspherical cells of the alga Chlorococcum
humicola; a central medulla with more closely-packed, greyish-brown hyphae
filaments. Section through an apothecium shows a hymenium layer
in the upper cortex with flask-shaped asci, each containing eight ascospores,
separated by numerous, narrow, thread-like paraphyses (3).
Powdered plant material
A greyish brown powder, abundant fragments of pseudoparenchyma consisting
of narrow-lumened, thick-walled hyphae from the marginal layer and
wide-lumened hyphae from the adjacent layer consisting of loosely entwined
hyphae, in the medullary zone of which, yellowish green algal cells about
15 m in diameter are embedded; occasionally marginal fragments of the thallus
with tube-like or cylindrical spermogonia, up to about 160 m wide and
400 m long. Many of the particles stain blue-black with iodine water (1).
General identity tests
Macroscopic and microscopic examinations and microchemical tests (1,
3), thin-layer chromatography for characteristic lichen acid profile (1),
and high-performance liquid chromatographic analysis of protolichesterinic
and fumarprotocetraric acids (8).
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 (9).
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