WHO monographs on selected medicinal plants - travolekar.ru

Rhizoma Picrorhizae
Description
A perennial herb with a long rhizome. The leaves are basal and alternate,
approximately 5–10 cm long. Spikes terminal. Calyx nearly equally in
5 segments. The corolla has 4 or 5 lobes, bilobiate with lobes more or less
spreading or nearly actinomorphic. Stamens 4, inserted on corolla tube,
slightly didynamous, as long as corolla or strongly exerted. Stigma capitate.
Fruit an acute capsule, tapered at top, dehiscing first septicidally and
then loculicidally into 4 valves, 12 mm long. Seeds numerous, ellipsoid:
seed coat very thick, transparent and alveolate. Pollen grains spheroidal,
3-colpate, with partial or perforate tectum, the partial tectum microreticulate,
colpus membrane smooth or sparsely granular (3, 10).
The corolla of Picrorhiza kurrooa Royle is 4–5 mm long and 5-lobed,
whereas the corolla of Neopicrorhiza scrophulariiflora is 9–10 mm long
and 4-lobed (3).
Plant material of interest: dried rhizome with root
General appearance
Rhizome: 2.5–12.0 cm long and 0.3–1.0 cm thick, subcylindrical, straight
or slightly curved, externally greyish-brown, surface rough due to longitudinal
wrinkles, circular scars of roots and bud scales and sometimes
roots attached, tip ends in a growing bud surrounded by a tufted crown
of leaves, in places cork exfoliates exposing dark cortex; fracture, short.
Root: thin, cylindrical, 5–10 cm long and 0.5–1.0 mm in diameter, straight
or slightly curved with a few longitudinal wrinkles and dotted scars,
mostly attached with rhizomes, dusty grey, fracture short, inner surface
black with whitish xylem (1, 2, 4).
Organoleptic properties
Odour: pleasant; taste: bitter (1).
Microscopic characteristics
The rhizome portion shows 20–25 layers of cork consisting of tangentially
elongated, suberized cells; cork cambium 1–2-layered; cortex singlelayered
or absent, primary cortex persists in some cases, 1 or 2 small vascular
bundles present in the cortex. Vascular bundles surrounded by
fibrous bundle sheath. Secondary phloem composed of parenchyma cells
and a few scattered fibres. Cambium 2–4-layered. Secondary xylem consists
of vessels, tracheids, fibres and parenchyma cells. Vessels vary in size
and shape, have transverse oblique articulation; tracheids long, thickwalled,
lignified, more or less cylindrical with blunt tapering ends. Starch
grains abundant, 25–105 μm in diameter. Root portion, when young,
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