Biochemical characterization of glycyrrhizin as an effective inhibitor for hyaluronidases from bovine testis

The inhibitory effects of several anti-inflammatory agents, including glycyrrhizin (GL), on the activities of hyaluronidases (HAses) purified from bovine testes and Streptomyces were investigated in vitro. It was found that (i) GL inhibits the activity of HAse (p55) from bovine testes in a dose-dependent manner, but does not affect HAse from Streptomyces; (ii) GL was the most effective of the compounds tested on bovine testis HAse activity (50% inhibition with approx. 3 microM GL); and (iii) glycyrrhetinic acid (GA), a derivative (oGA) of GA and diglucuronic acid had no detectable effects on HAse activity at 9.0 microM. The GL-induced inhibition of HAse activity is uncompetitive for its substrates. Data are provided to support the contentions that (i) bovine testis HAse (p55) is a GL-binding protein; and (ii) GL acts as a potent inhibitor of HAse in vitro.