Anti-inflammatory Glycyrrhetinic acid inhibits the
enzymes (
15-hydroxyprostaglandin dehydrogenase and delta-13-prostaglandin reductase) that metabolize the
prostaglandins PGE-2 and PGF-2α to their respective, inactive 15-keto-13,14-dihydro
metabolites. This increases prostaglandins in the digestive system. Prostaglandins inhibit gastric secretion, stimulate
pancreatic secretion and mucous secretion in the
intestines, and markedly increase intestinal motility. They also cause cell proliferation in the
stomach. The effect on
gastric acid secretion, and promotion of mucous secretion and cell proliferation shows why licorice has potential in treating peptic ulcers. Excessive consumption of glycyrrhetinic acid can cause a significant rise in blood pressure.
Liquorice root should not be consumed during pregnancy. The structure of glycyrrhetinic acid is similar to that of
cortisone. Both molecules are flat and similar at positions 3 and 11. This might be the basis for liquorice's
anti-inflammatory action.
Hypertensive 3-β-D-(Monoglucuronyl)-18-β-glycyrrhetinic acid, a metabolite of glycyrrhetinic acid, inhibits the conversion of 'active'
cortisol to 'inactive'
cortisone in the
kidneys. This occurs via inhibition of the enzyme
11-β-hydroxysteroid dehydrogenase. As a result, cortisol levels become high within the collecting duct of the kidney. Cortisol has intrinsic mineralocorticoid properties (that is, it acts like
aldosterone and increases
sodium reabsorption) that work on ENaC channels in the collecting duct.
Hypertension develops due to this mechanism of sodium retention. People often have high blood pressure with a low
renin and low
aldosterone blood level. The increased amounts of cortisol binds to the unprotected, nonspecific mineralocorticoid receptors and induce sodium and fluid retention,
hypokalaemia, high blood pressure, and inhibition of the renin-angiotensin-aldosterone system. Therefore, licorice should not be given to patients with a known history of hypertension in doses sufficient to inhibit 11-β-hydroxysteroid dehydrogenase. ==Derivatives==