Glycyrrhetic acid monoglucuronide: sweetness concentration–response and molecular mechanism as a naturally high-potency sweetener

Glycyrrhetic acid monoglucuronide (GAM) is obtained from the natural sweetener glycyrrhizin through enzymolysis. Its sweetness concentration–response (C–R) behavior in room-temperature in water was determined using two-alternative forced choice discrimination tests. The C–R equation of resultant hyperbolic curve relating sucrose equivalent (SE, %) to GAM concentration ([GAM], mg/L) was SE = 19.6 × [GAM]/(194.8 + [GAM]). From the C–R function, Pw (2) of GAM, relative to a 2% (w/v) sucrose reference, is more than 900, which has much higher potency than its precursor glycyrrhizin. Molecular modeling showed that GAM is finely bound into protein 1EWK through conventional hydrogen bonds, π-Alkyl interactions and Van der Waals bonds, which exhibited better protein inclusion than Glycyrrhizin. Thus, GAM could be developed as a new zero-calorie, naturally high-potency sweetener.