• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.125-125
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• 1998

Glycyrrhizin (18$\beta$-glycyrrhetic acid $\beta$-D-glucuronyl a-D-glucuronic acid, GL), a main component of liquore extract (Glycyrrhiza glabra), is ingested orally as a component in the oriental medicine. By human intestinal bacteria, glycyrrhizin (18$\beta$-glycyrrhetinic acid $\beta$-D-glucuronyl a-D-glucuronic acid, GL) was metabolized to glycyrrhetinic acid (GA): main pathway metabolizing GL to GA by glucuronidases of Bacteroides J-37 (Kim et al., 1997) and Eubacterium sp strain GLH (Akao et al., 1987) and minor pathway metabolizing GL to GA via 18$\beta$-glycyrrhetic acid D-glucuronic acid (GAMG) by $\beta$-glucuronidase of Streptococcus LJ-22 and glucuronidases of Bacteroides J-37 / E. coli. $\beta$-Glucuronidase from Streptococcus LJ-22 hydrolyzed GL to GAMG, not GA. $\beta$-Glucuronidase of Streptococcus LJ-22 hydrolyzed $\beta$-glucuronic acid conjugates of polysaccharides rather than aglycone-$\beta$-glucuronides Optimal pH of Streptococcus LJ-22 $\beta$-glucuronidase was 5-6 and its molecular weight was 250 kDaltons. Km for GL was 0.37mM.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.57-60
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• 2004

Glycyrrhizin (18$\beta$-glycyrrhetinic acid-3-O-$\beta$-D-glucuronopyranosyl-(1$\rightarrow2)-\beta$-D-glucuronide, GL) was transformed to 18$\beta$-glycyrrhetinic acid-3-O-$\beta$-D-glucuronide (GAMG) by Streptococcus LJ-22. The antiallergic activities of GL and GAMG was measured using a RBL cell assay system and contact hypersensitivity model mice. GAMG exhibited anti-allergic activity with $IC_{50}$ values of 0.28 mM. GAMG, which is sweeter than GL, and 18$\beta$-glycyrrhetinic acid, which is a GAMG metabolite by human intestinal bacteria, also inhibited the passive cutaneous anaphylaxis and skin contact inflammation. In conclusion, GAMG may be useful as a new sweet food additive and an anti-allergic agent.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.792-799
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• 2005

Two novel $\beta$-glucuronidases, which metabolize glycyrrhizin (GL) to 18$\beta$-glycyrrhetinic acid-3-O-$\beta$-D-glucuronide (GAMG), were purified from Streptococcus LJ-22 isolated from human intestinal microflora. $\beta$-Glucuronidases I and II were purified to apparent homogeneity, using a combination of ammonium sulfate fractionation, butyl toyopearl, Q-Sepharose, hydroxyapatite Ultrogel, and GL-attached Sepharose column chromatographies, with the final specific activities of 137 and 190 nmole/min/mg, respectively. The molecular sizes of both $\beta$-glucuronidases were found to be 140 kDa by gel filtration, and they consisted of two identical subunits (M.W. 67 kDa by SDS-PAGE). $\beta$-Glucuronidases I and II showed optimal activity at pH 7.0 and pH 6.5, respectively. Both purified enzymes were potently inhibited by $Cu^{2+}$ and PCMS, and had maximum activity on glycyrrhizin, but did not hydrolyze p-nitrophenyl-$\beta$-glucuronides, baicalin, or GAMG These findings suggest that the biochemical properties and substrate specificities of these enzymes are different from those of the previously purified $\beta$-glucuronidases. This is the first reported purification of sugar (not aglycone)-recognizing $\beta$-glucuronidases from intestinal bacteria.

• Archives of Pharmacal Research
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• v.23 no.2
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• pp.172-173
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• 2000

The relationship between the metabolites of glycyrrhizin (18$\beta$-glycyrrhetinic acid-3-O--D-glu-curonopyranosyl-($1{\rightarrow}2$)-$\beta$-D-glucuronide, CL) and their biological activities was investigated. By human intestinal microflora, CL was metabolized to 18$\beta$-glycyrrhetinic acid (GA) as a main product and to 18$\beta$-glycyrrhetinic acid-3-O-$\beta$-D-glucuronide (GAMG) as a minor product. The former reaction was catalyzed by Eubacterium L-8 and the latter was by Streptococcus LJ-22. Among GL and its metabolites, GA and GAMG had more potent in vitro anti-platelet aggregation activity than GL. GA also showed the most potent cytotoxicity against tumor cell lines and the potent inhibitory activity on rotavirus infection as well as growth of Helicobacter pylori. GAMG, the minor metabolite of GL, was the sweetest.