NIS - libdoc.who.int - World Health Organization

WHO monographs on medicinal plants commonly used in the Newly Independent States (NIS)
Glycyrrhizin reduces the toxic action of carbon tetrachloride- and galactosamine-induced
cytotoxicity in cultured rat hepatocytes, through its
antioxidant activity (9, 27). Glycyrrhizin inhibited histamine release from
rat mast cells and prevented carbon tetrachloride-induced liver lesions and
macrophage-mediated cytotoxicity (27). Intragastric administration of a
flavonoid fraction isolated from Radix Glycyrrhizae to mice protected
against carbon tetrachloride hepatotoxicity (39). Glycyrrhizin protected
the liver apparently through its membrane stabilization effects (27).
The anti-inflammatory and antiallergic actions of the drug have been
attributed to the corticosteroid-like activity of glycyrrhizin and glycyrrhetic
acid (enoxolone). These compounds act indirectly by potentiating
the activity of corticosteroids. In vitro, glycyrrhetic acid inhibits
Δ 4 β-reductase, an enzyme that competitively inactivates steroid hormones,
and 11β-hydroxysteroid dehydrogenase, the enzyme that deactivates cortisol
(27). Glycyrrhizin given intraperitoneally suppressed contact dermatitis
in mice, and was more effective than prednisolone, but no effects
were observed after oral administration (9).
In vitro, the drug inhibits the growth of Bacillus subtilis (40), Mycobacterium
tuberculosis (41), Aspergillus spp. (42), Staphylococcus aureus,
Mycobacterium smegmatis, and Candida albicans (43).
Clinical pharmacology
Oral administration of Radix Glycyrrhizae to 15 patients with peptic ulcer
reduced symptoms and improved healing in 75% of the cases (44).
Glycyrrhetic acid (enoxolone), the active constituent, produced its antiulcer
activity by inhibiting 15-hydroxyprostaglandin dehydrogenase and
Δ 13 -prostaglandin reductase (45). Inhibition of these two enzymes stimulated
an increase in the concentration of prostaglandins E and F 2α
in the
stomach, which promoted the healing of peptic ulcers owing to a cytoprotective
effect on the gastric mucosa (45). Carbenoxolone, a derivative
of glycyrrhetic acid, has been used clinically for years in the treatment of
gastric and duodenal ulcers (46).
Oral administration of deglycyrrhizinated liquorice (380 mg, 3 times
daily) to 169 patients with chronic duodenal ulcers was as effective as
antacid or cimetidine treatments (47). These results indicate that, in addition
to glycyrrhetic acid, other unidentified constituents of Radix Glycyrrhizae
contribute to its antiulcer activity.
Reports on the usefulness of liquorice extracts on body fluid homeostasis
in patients with Addison disease are contradictory. One study found
no positive effects (48), while three other studies noted an increase in
weight gain and sodium retention (49–51).
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