Page 252 - Pharmacognosy 2 PG303

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

On micro-sublimation, powdered Gentian gives pale yellow almost straight
crystals, isolated or in groups, insoluble in water, in alcohol and in ether, but is
soluble in chloral hydrate T. S. and in KOH T. S., giving a yellow but no red solution
(distinction from Rumex).

Tests for Purity
Powdered Gentian contains no sclereids or fibers (Rumex species, Coco
Nutshell, or stems of Gentian), no starch granules over 20 µ in diameter (foreign
starches).

Constituents
Seco-iridoid bitter substances including 2-3% gentiopicroside (gentiopicrin),
the main component, and swertiamarin and sweroside. Xanthone derivatives
(gentisin, isogentisin, gentioside,..etc.).

The darker internal color of the dried European root as compared with the
dried Japanese product may be due to greater hydrolysis of the colorless
glycosides to the yellow xanthones during the drying process. Besides
saccharose, and the trisaccharide gentianose, there is the bitter-tasting
gentiobiose (5-8%), also present are phytosterols and pectins, or similar gel-forming
substances, which may be responsible for the swelling that the drug undergoes
when moistened. The alkaloids, e.g., gentianine are probably artifacts arising during
work-up. The small amount of essential oil obtained on distillation has a
complex composition. Starch is absent.

Uses
Strong appetite bitter stimulant, and as tonic. By stimulating the taste buds
and affecting the encephalic phase of the secretion, the drug brings about reflex
promotion of gastric juice and saliva production. It also has a cholagogue effect.

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