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the drug have been confirmed by the results of laboratory and clinical studies. 608,611 In essential
hypertension, glycyrrhizin caused a marked reduction in elevated plasma renin activity, with a con-
comitant reduction in serum potassium concentration and plasma aldosterone.
The antitussive properties have been evaluated using the water-extracted (WE) polymeric frac-
tion of Glycyrrhiza glabra . This arabinogalactan protein-enriched fraction, 85% or more of which
becomes precipitated with Yariv reagent, consisted mainly of 3- and 3,6-linked galactopyranosyl
and 5- and 3,5-linked arabinofuranosyl residues. Per oral administration of this polymer in a dose
of 50 mg/kg body weight decreased the number of citric acid-induced cough efforts in guinea pigs
more effectively than codeine. It did not induce significant change in the values of specific airway
resistance or provoke any observable adverse effects. 609
The cardioprotective effect of Glycyrrhiza glabra against ischemia-reperfusion (I-R) injury
induced by ligation of the left anterior descending coronary artery (LADCA) in rats has been
reported. 610 Ligation of the LADCA for 45 min followed by 60 min of reperfusion has induced
significant ( p < 0.05) heart dysfunction as evidenced by a significant ( p < 0.05) decrease in mean
arterial pressure (MAP), heart rate (HR), and contractility; (+)LVdP/dtmax and relaxation; and
(−)LVdP/dtmax along with increased left ventricular end diastolic pressure (LVEDP). Ligation
induced I-R injury also significantly ( p < 0.05) decreased myocyte injury enzymes, creatine phos-
phokinase-MB (CK-MB) isoenzyme, and lactate dehydrogenase (LDH) as well as antioxidant
enzymes; and SOD, CAT, and glutathione peroxidase (GSH-Px). Furthermore, I-R injury also
induced lipid peroxidation, as evidenced by significant ( p < 0.05) increase in malondialdehyde
(MDA) formation and histological perturbations concomitant to depletion of GSH from the heart.
However, pretreatment with G. glabra significantly ( p < 0.05) prevented the depletion of the anti-
oxidant enzymes; SOD, CAT, GSH-Px, and myocyte injury marker enzymes; CK-MB isoenzyme
and LDH. Pretreatment with G. glabra also prevented GSH depletion and inhibited lipid peroxida-
tion in the heart. In addition to improving biochemical indices of myocardial function, G. glabra
significantly ( p < 0.05) reinstated MAP, HR, (±)LVdP/dtmax and attenuated an abrupt rise in
LVEDP. Histopathological preservation evidenced by reduced infiltration of cells and myonecrosis
depicted the myocardial salvaging effect of G. glabra . These findings suggest the cardioprotective
potential of G. glabra against myocardial infarction by amelioration of oxidative stress and favor-
able modulation of cardiac function.
Clinical Properties — Clinical reports on glycyrrhizin, its aglycone, or any of the semisyn-
thetic derivatives are usually listed under the generic name of carbenoxolone, which is actually
the name of the semisynthetic succinic acid ester of 18-glycyrrhetic acid. Clinical studies have
shown that liquorice exerts an inhibitory activity against prostaglandin and thromboxane synthesis
in humans. 611 The drug is used as oral tablets at a dose of 5-10 g or is incorporated into tropical
preparations for the treatment of skin diseases. Liquorice roots are used in Japan and China in the
treatment of allergic inflammation and atopic dermatitis. 606 Its deoxycorticosterone effects have led
to its use in the treatment of rheumatoid arthritis, Addison's disease, and various inflammatory con-
ditions. It is a major ingredient in the Japanese Kampo drugs and features in nearly every Kampo
prescription included in recent reviews. 612 In the drug preparation called Shakuya-du-kanzo-to (Tj-
68), glycyrrhiza root and peony root are used in equal proportions in the treatment of inflammation
and hyperandrogenism. Other clinical uses of glycyrrhiza, including the treatment of gastric ulcer,
cancer, and AIDS, are discussed elsewhere in related texts on phytotherapy. Its use for the treat-
ment of ulcer may be due partly to its effect on adhesion of harmful organisms to gut. It has been
shown that an aqueous extract (1 mg/ml) of Glycyrrhiza glabra significantly inhibited the adhesion
of Helicobacter pylori to human stomach tissue. 609 This effect was related to the polysaccharides
isolated from the extract, with one purified acidic fraction (0.25 SPB) as the main active polymer.
Purified polysaccharides did not exhibit direct cytotoxic effects against Helicobacter pylori and did
not influence hemagglutination. In addition, raw polysaccharides from Glycyrrhiza glabra were
shown to have strong antiadhesive effects against Porphyromonas gingivalis . 1078
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