NIS - libdoc.who.int - World Health Organization

Radix Glycyrrhizae
Dilute alcohol-soluble extractive
Not less than 25% (7).
Pesticide residues
To be established in accordance with national requirements. Normally,
the maximum residue limit of aldrin and dieldrin for Radix Glycyrrhizae
is not more than 0.05 mg/kg (20). For other pesticides, see WHO guidelines
on quality control methods for medicinal plants (18) and guidelines
for predicting dietary intake of pesticide residues (21).
Heavy metals
Recommended lead and cadmium levels are no more than 10 and 0.3 mg/
kg, respectively, in the final dosage form of the plant material (18).
Radioactive residues
For analysis of strontium-90, iodine-131, caesium-134, caesium-137, and
plutonium-239, see WHO guidelines on quality control methods for medicinal
plants (18).
Other purity tests
Alcohol-soluble extractive, chemical, and foreign organic matter tests to
be established in accordance with national requirements.
Chemical assays
Assay for glycyrrhizin (glycyrrhizic acid, glycyrrhizinic acid) content (at
least 4%) by means of spectrophotometric (1, 2), thin-layer chromatographic–densitometric
(22, 23) or high-performance liquid chromatographic
methods (24–26).
Major chemical constituents
The major constituents are triterpene saponins. Glycyrrhizin (glycyrrhizic
acid, glycyrrhizinic acid) is the major component (2–9%); minor components
occur in proportions that vary depending on the species and geographical
location (24–27). Glycyrrhizin occurs as a mixture of potassium
and calcium salts (9). It is a monodesmoside, which on hydrolysis releases
two molecules of d-glucuronic acid and the aglycone glycyrrhetic (glycyrrhetinic)
acid (enoxolone) (28). Glycyrrhizin is generally regarded as
the active principle of Radix Glycyrrhizae and is responsible for its sweetness,
which is 50 times that of sucrose (27). Flavonoid constituents include
liquiritigenin and isoliquiritigenin.
165