Page 236 - Pharmacognosy 2 PG303 (1)

Pharmacognosy-2 (PG303) Level 2 Clinical Pharmacy-Pharm D

It is native in North-western China and Tibet, cultivated to some extent
in Europe. The drug is imported from China and India; Pakistan also supplies
rhubarb, which mostly doesn't meet pharmacopeial standards.

Macroscopical Characters
The drug consists of peeled underground organs (turnip-shaped roots
with very small rhizomes). The ochre-yellow to brownish pieces are often
covered on the outside with powder and they exhibit orange striations or an
orange-red mottling. The fracture is granular and crumbly (not fibrous) and
reddish brown; Odor: characteristic and faintly smoky. Taste: somewhat bitter
and harsh and slightly astringent. It is very gritty between the teeth and colors
the saliva yellow.

Chinese rhubarb. Shensi; A. Shensi flat. B, Shensi round. C. end of
Shensi round. D. detail of the reticulation. h, hole with embedded string;
k, knife-mark; l.s.p., star spot cut longitudinally; m.r., medullary ray; r,
reticulation; s, starchy parenchyma; s.p.,star-spot.

Rhubarb occurs in sub-cylindrical, barrel-shaped, conical, plano-convex,
or rectangular pieces, each occasionally; showing a perforation; 5-17 cm long,
4-10 cm wide. Externally, it is usually dusted with a fine bright, brownish yellow
powder and showing longitudinal reddish-brown lines and dots, embedded in a
grayish white ground tissue. This. frequently forms a network of whitish lines,
in the rneshess of which are alternating white phloem parenchyma, and orange
or brownish red lines, the medullary rays, and occasional star spots and rarely
small patches of brown cork. The pieces are compact, firm, hard and heavy.
Fracture, granular and uneven. Internally, it is pinkish brown to grayish, not
discolored or lacunous. It shows numerous reddish-brown lines, embedded in

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