Carbenoxolone, a synthetic derivative of glycyrrhetinic acid, is a licensed drug (in the UK) for oesophageal ulceration and inflammation. Other uses include treatment of oral and perioral lesions.
Carbenoxolone (aka Carbenoxolone, CBX) is also used as a blocker of the enzyme 11β-hydroxysteroid dehydrogenase (11β-HSD), of pannexon membrane channels (comprising 6 subunits of pannexin) and the related innexon channels (consisting of invertebrate innexins), and at higher concentrations, as a blocker of connexon channels ("hemichannels" made up of 6 connexin subunits each) and of gap junctions (2 connexons joined together). Animal and in vitro studies suggest that this blockade can increase insulin sensitivity.
Carbenoxolone has also been investigated for nootropic effects.
This research started from an observation that long-term exposure to glucocorticoids may have negative effects on cognition. Carbenoxolone may decrease the amount of active glucocortocoid in the brain, because the drug inhibits 11Beta-hydroxysteroid dehydrogenase type 1, an enzyme which degrades cortisol, an active glucocorticoid to cortisone (inactive). In the research trial investigating this use of carbenoloxone, it was shown that the drug improved verbal fluency in elderly healthy men (aged 55–75). In type 2 diabetics aged 52–70, the drug improved verbal memory. However, potassium-sparing diureticamiloride was co-administered with carbenoxolone, since carbenoxolone used by itself may cause hypertension by increasing cortisol in the kidneys.